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  • 201.
    Olsson, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Nilsson, Kerstin A
    Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lindblom, Gunnar
    Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Karlsson, Henrik
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Agnetha
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Bedömning av bildkvalitet med hjälp av VGC på helkroppsscanning vid skelettscintigrafi2010Conference paper (Other academic)
  • 202.
    Olsson, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Sundström, Torbjörn
    Umeå universitet .
    Larsson, Anne
    Umeå universitet .
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Agnetha
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    A strategy for optimisation of nuclear medicine examinations – application to rCBF SPECT2010Conference paper (Other academic)
  • 203.
    Olsson, Anna
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Ärlig, Åsa
    County Hospital Ryhov, Jönköping.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Gustafsson, Agnetha
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Evaluation of reconstruction techniques in regional cerebral blood flow SPECT using trade-off plots: A Monte Carlo study2007In: Nuclear medicine communications, ISSN 0143-3636, E-ISSN 1473-5628, Vol. 28, no 9, p. 719-725Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND AIM: The image quality of single photon emission computed tomography (SPECT) depends on the reconstruction algorithm used. The purpose of the present study was to evaluate parameters in ordered subset expectation maximization (OSEM) and to compare systematically with filtered back-projection (FBP) for reconstruction of regional cerebral blood flow (rCBF) SPECT, incorporating attenuation and scatter correction. METHODS: The evaluation was based on the trade-off between contrast recovery and statistical noise using different sizes of subsets, number of iterations and filter parameters. Monte Carlo simulated SPECT studies of a digital human brain phantom were used. The contrast recovery was calculated as measured contrast divided by true contrast. Statistical noise in the reconstructed images was calculated as the coefficient of variation in pixel values. RESULTS: A constant contrast level was reached above 195 equivalent maximum likelihood expectation maximization iterations. The choice of subset size was not crucial as long as there were > or = 2 projections per subset. The OSEM reconstruction was found to give 5-14% higher contrast recovery than FBP for all clinically relevant noise levels in rCBF SPECT. The Butterworth filter, power 6, achieved the highest stable contrast recovery level at all clinically relevant noise levels. The cut-off frequency should be chosen according to the noise level accepted in the image. CONCLUSION: Trade-off plots are shown to be a practical way of deciding the number of iterations and subset size for the OSEM reconstruction and can be used for other examination types in nuclear medicine.

  • 204.
    Olsson, Sara
    et al.
    Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Malke, Zelga
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Larsson, Peter
    Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Carlsson Tedgren, Åsa
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    A system for mailed dose audit in radiotherapy using lithium formate EPR dosimetry2011Conference paper (Refereed)
  • 205.
    Pachnerova Brabcova, Katerina
    et al.
    Academic Science Czech Republic, Czech Republic .
    Ambrozova, Iva
    Academic Science Czech Republic, Czech Republic .
    Koliskova, Zlata
    Academic Science Czech Republic, Czech Republic .
    Malusek, Alexandr
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Academic Science Czech Republic, Czech Republic .
    Uncertainties in linear energy transfer spectra measured with track-etched detectors in space2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 713, p. 5-10Article in journal (Refereed)
    Abstract [en]

    Polyallyldiglycol carbonate-based track-etched detectors can measure linear energy transfer (LET) spectra of charged particles. Accuracy of the spectra is affected by many factors whose effects are difficult to quantify. Typically, only uncertainty arising from the randomness of particle detection is reported in scientific literature. The aim of this paper is to classify the sources of uncertainties of an LET spectrum measurement and provide a simple model for the calculation of the combined uncertainty. The model was used for a spectrum measured with the track-etched detector (Harzlas TD-1) on board of the International Space Station from May-October 2009. For some spectrum bins the largest contribution to the combined uncertainty came from the uncertainty arising from the randomness of particle detection. For other bins it came from the uncertainty of the calibration curve. Contribution from the cross talk between bins was small for most of the bins as the width of the bins was relatively large compared to the intrinsic resolution of the track-etched detector. The analysis showed that sources of uncertainties other than the randomness of particle detection should not, in general, be neglected.

  • 206.
    Palhagen, Sven E
    et al.
    Karolinska University.
    Ekberg, Stefan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Walinder, Jan
    University of Gothenburg.
    Granerus, Ann-Kathrine
    Linköping University, Department of Clinical and Experimental Medicine, Geriatric . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine.
    Granerus, Göran
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    HMPAO SPECT in Parkinsons disease (PD) with major depression (MD) before and after antidepressant treatment2009In: JOURNAL OF NEUROLOGY, ISSN 0340-5354, Vol. 256, no 9, p. 1510-1518Article in journal (Refereed)
    Abstract [en]

    Previously we suggested that major depression (MD) in Parkinsons disease (PD) could be an indication of a more advanced and widespread neurodegenerative process, as PD symptoms were more severe in those with depression. We also found a different antidepressant response with SSRI medication in PD patients with depression compared to depressed patients without PD. This indicates diverse underlying pathophysiological mechanisms. Investigations using single-photon emission computed tomography (SPECT), measuring regional cerebral blood flow (rCBF), may contribute to enlighten the neurobiological substrates linked to depressive symptoms. SPECT was performed in order to compare rCBF in MD patients with and without PD. The study included 11 MD patients with PD, 14 nondepressed PD patients and 12 MD patients without PD. All patients were followed for 12 weeks with repeated evaluation of depressive as well as PD symptoms. Anti-Parkinsonian treatment remained unchanged during the study. Antidepressant treatment with SSRI (citalopram) was given to all patients with MD. SPECT was performed before and after 12 weeks of antidepressant treatment. rCBF was found to differ between PD patients with and without MD, as well as between MD patients with and without PD, both at baseline and concerning the response to treatment with SSRI (citalopram). In patients with PD the rCBF was found to be decreased in preoccipital and occipital regions, a finding more common when PD was combined with MD. In summary, larger cortical areas were found to be involved in depressed PD patients, both with hyperactivity (reciprocal to basal degeneration in PD and maybe dopaminergic treatment) and with hypoactivity (probably due to organic lesions leading to hypoperfusion). These observations support our hypothesis that PD combined with MD is an expression of a more advanced and widespread neurodegenerative disorder.

  • 207.
    Persliden, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Digital radiology and the radiological protection of the patient2004In: European Radiology, Supplement, ISSN 1613-3749, Vol. 14, no 1, p. 50-58Article in journal (Refereed)
    Abstract [en]

    The wide dynamic range of the digital detectors and the capabilities of post-processing allow obtaining more information from the radiographic images and avoiding retakes. Using phosphor plates in the image formation process, it has been possible to lower the dose to the patient. In digital radiography, several authors report the possibility to substantially lower the radiation dose to the patient while maintaining or even increasing the image quality. In conventional radiography, increased patient dose results in a dark image. In digital radiography the brightness of the image does not depend on patient dose. High patient doses can result in low-noise, high-contrast digital images, therefore, optimization of examinations is of vital importance in digital radiography. Special emphasis should be directed to paediatrics. The digital technique is very useful in reducing the dose both in fluoroscopy and radiography, however, special procedures for children are needed. © Springer-Verlag 2004.

  • 208.
    Persliden, Jan
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Sandborg, Michael
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Conversion factors between the energy imparted to the patient and air collision kerma integrated over beam area in paediatric radiology1993In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 34, p. 92-98Article in journal (Refereed)
    Abstract [en]

    n/a

  • 209.
    Persson, Anders
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Kalra, Mannudeep K.
    Massachusetts General Hospital, Boston, USA .
    Quick, Petter
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Dahlström, Nils
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Sandborg, Michael
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Singh, Sarabjeet
    Massachusetts General Hospital, Boston, USA .
    Use of iterative reconstruction in image space (IRIS) to improve accetability of 50 and 100 mAs abdominal CT: comparison of standrad of care 200 mAs filtered back projection CT images2010In: SSK15-04, 2010Conference paper (Other academic)
  • 210.
    Pettersson, Håkan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Fälth-Magnusson, Karin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Persliden, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Scott, M.
    Department of Statistics, University of Glasgow, Glasgow G12 8QW, United Kingdom.
    Radiation risk and cost-benefit analysis of a paediatric radiology procedure: Results from a national study2005In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 78, no 925, p. 34-38Article in journal (Refereed)
    Abstract [en]

    A national study was performed to investigate radiation doses and associated risks to patients during X-ray fluoroscopy-guided small intestinal biopsies in the investigation of coeliac disease. Thermoluminescent dosemeters (TLD) and questionnaires were sent to 42 of the 43 paediatric departments in Sweden performing these biopsies. During the study period (2 × 3 weeks) 257 biopsies were recorded, representing about 10% of annually performed paediatric investigations. The results show that the absorbed dose during biopsy ranged from 0.04 mGy to 23.8 mGy (mean 1.87 mGy). The fluoroscopy time ranged from 2 s to 663 s (mean 60 s). The collective dose from the procedure amounts to 4.7 manSv year-1. Thus, the annual excess cancer mortality, including severe hereditary effects, can be estimated at 0.6-0.7 cases per year. However, significant dose saving can be obtained by proper choice of sedation and biopsy equipment. © 2005 The British Institute of Radiology.

  • 211.
    Pettersson, Håkan
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Povinec, P. P.
    Osvath, I.
    Baxter, M. S.
    Ballestra, S.
    Carroll, J.
    Gastaud, J.
    Harms, I.
    Summary of IAEA-MEL's investigation of Kara Sea radioactivity and radiological assessment1997In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 35, no 7-12, p. 235-241Article in journal (Refereed)
    Abstract [en]

    IAEA-MEL participated in five expeditions to the Kara Sea with the aim of assessing the radiological consequences of dumped radioactive wastes in the Novaya Zemlya Bays and Trough. The programme included sampling, in-situ underwater investigations, laboratory analyses of water, sediment and biota samples, the development of a marine radioactivity database, modelling and radiological assessment, the organization of intercomparison exercises and the evaluation of distribution coefficients. Radiometric investigations have shown that no radiologically significant environmental contamination has occurred. Leakages which have led to locally increased levels of radionuclides in sediment have only been observed in Stepovoy and Abrosimov Bays. Computer modelling results suggest that only radiological effects on local and regional scales may be of importance. The global radiological impact of the disposals in the Arctic Seas will be negligible.

  • 212.
    Pham, M K
    et al.
    IAEA.
    Betti, M
    IAEA.
    Povinec, P P
    Comenius University.
    Benmansour, M
    Centre Natl Energie Science and Tech Nucl, Rabat.
    Buenger, V
    Senatsverwaltung Gesundheit Umwelt and Verbraucher.
    Drefvelin, J
    Norwegian Radiation Protection Authority.
    Engeler, C
    WGMLA Radiochem.
    Flemal, J M
    Science Institute for Public Health.
    Gasco, C
    Centre Invest Energet MedioAmbient and Technology.
    Guillevic, J
    Institute Radioprotect and Surette Nucl.
    Gurriaran, R
    IRSN DEI STEME LMRE.
    Groening, M
    IAEA.
    Happel, J D
    University of Miami.
    Herrmann, J
    Bundesamt Seeschifffahrt and Hydrog.
    Klemola, S
    Radiat and Nucl Safety Author.
    Kloster, M
    Senatsverwaltung Gesundheit Umwelt and Verbraucher.
    Kanisch, G
    Johann Heinrich von Thunen Institute.
    Leonard, K
    Centre Environm Fisheries and Aquaculture Science.
    Long, S
    Radiol Protect Institute Ireland.
    Nielsen, S
    Riso Natl Lab.
    Oh, J-S
    Natl Oceanog Centre Southampton.
    Rieth, P U
    Johann Heinrich von Thunen Institute.
    Oestergren, I
    Swedish Radiat Safety Author.
    Pettersson, Håkan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Pinhao, N
    Institute Tecnol and Nucl, Sacavem, Portugal .
    Pujol, L
    Centre Estudios Expt and Obras Publ.
    Sato, K
    Japan Chemistry Anal Centre.
    Schikowski, J
    University of Gottingen.
    Varga, Z
    Hungarian Academy of Science.
    P Vartti, V
    Radiat and Nucl Safety Author.
    Zheng, J
    Natl Institute Radiol Science.
    A certified reference material for radionuclides in the water sample from Irish Sea (IAEA-443)2011In: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY, ISSN 0236-5731, Vol. 288, no 2, p. 603-611Article in journal (Refereed)
    Abstract [en]

    A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (H-3, K-40, Sr-90, Cs-137, U-234, U-235, U-238, Pu-238, Pu239+240 and Am-241) have been certified, and information values on massic activities with 95% confidence intervals are given for four radionuclides (Th-230, Th-232, Pu-239 and Pu-240). Results for less frequently reported radionuclides (Tc-99, Th-228, Np-237 and Pu-241) are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in water samples, for the development and validation of analytical methods and for training purposes. The material is available in 5 L units from IAEA (http://nucleus.iaea.org/rpst/index.htm).

  • 213.
    Pham, M.K.
    et al.
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Sanchez-Cabeza, J.A.
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Povinec, Pavel
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Arnold, D.
    Physikalisch-Technische Bundesanstalt, Braunschweig, Germany.
    Benmansour, M.
    Centre National de l’Energie, des Sciences et des Techniques Nucle´aires (CNESTEN), Rabat, Morocco.
    Bojanowski, R.
    Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland.
    Carvalho, F.
    Instituto Tecnolo´gico e Nuclear, Departamento de Protecc-a˜o Radiolo´gica e Seguranc-a Nuclear, Sacave´m, Portugal.
    Kim, C.K.
    Department of Radiological Environmental Assessment, Korea Institute of Nuclear Safety, Yo-song, Taejon, Korea.
    Esposito, M.
    Laboratorio di Ingegneria Nucleare, Universita` di Bologna, Bologna, Italy.
    Gastaud, J.
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Gasco, C.L.
    CIEMAT-DIAE, Radioecologia del Medio Acuatico, Madrid, Spain.
    Ham, G.J.
    National Radiological Protection Board, Chilton, Didcot, Oxon, UK.
    Hegde, A.G.
    Environmental Survey Laboratory, Bhabha Atomic Research Center, Tarapur Atomic Power Station, Maharashtra, India.
    Holm, E
    Department of Medical Radiation Physics, Lund University Hospital, Lund, Sweden.
    Jaskierowicz, D
    Lab. d’Analyses de Surveillance et d’Expertise de la Marine, Base Navale de Cherbourg, Cherbourg, France.
    Kanisch, G.
    Federal Research Centre for Fisheries, Institute of Fisheries Ecology, Hamburg, Germany.
    Llaurado, M.
    Lab. de Radiologia Ambiental, Dept. de Quimica Analitica, Facultat de Quimica, Universitat de Barcelona, Spain.
    La Rosa, J.
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Lee, S.H.
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Liong We Kwong, L
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Le Petit, G
    Commissariat a` l’Energie Atomique, DASE/SRCE, Bruye`res-le-Chaˆtel, France.
    Maruo, Y.
    Health and Safety Division, JNC Tokai works, Tokai-mura, Naka-gun, Ibaraki, Japan.
    Nielsen, S.P.
    Risoe National Laboratory, Roskilde, Denmark.
    Oh, J.S.
    Geosciences Advisory Unit, National Oceanography Centre, Southampton, UK.
    Oregioni, B
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Palomares, J
    CIEMAT, Instituto de Medio Ambiente, Radioecologia del Medio Acuatico, Madrid, Spain.
    Pettersson, Håkan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Rulik, P.
    National Radiation Protection Institute, Prague, Czech Republic.
    Ryan, T. P.
    Radiological Protection Institute of Ireland, Dublin, Ireland.
    Sato, K.
    Japan Chemical Analysis Center, Inage-Ku, Chiba-Shi, Chiba, Japan.
    Schikowski, J.
    Physikalische Chemie, Isotopenlabor, Göttingen, Germany.
    Skwarzec, B
    Faculty of Chemistry, Chair of Analytical Chemistry, Radiochemical Laboratory, Gdansk, Poland.
    Smedley, P.A.
    CEFAS, Lowestoft Laboratory, Lowestoft, Suffolk, UK.
    Tarja´n, S.
    National Food Investigation Institute, Budapest , Hungary.
    Vajda, N
    Institute of Nuclear Techniques, Budapest University of Technology and Economics, Budapest, Hungary.
    Wyse, E
    International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), Monaco.
    Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)2006In: Applied Radiation and Isotopes, ISSN 0969-8043, E-ISSN 1872-9800, Vol. 64, p. 1253-1259Article in journal (Refereed)
    Abstract [en]

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) isdescribed and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu,239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six otherradionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np)and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of theanalysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. Thematerial is available from IAEA, Vienna, in 100 g units.r 2006 Elsevier Ltd. All rights reserved.

  • 214.
    Povinec, Pavel
    et al.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Pham, M.K.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Sanchez-Cabeza, J. A.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Barci-Funel, G.
    Universite Nice-Sophia Antipolis, Laboratoire de Radiochimie et de RadioEcologie, Nice, France.
    Bojanowski, R.
    Institute of Oceanography, Sopot, Poland.
    Boshkova, T.
    Sofia University, Faculty of Physics, Sofia, Bulgaria.
    Burnett, W. C.
    Florida State University, Department of Oceanography, Tallahassee, USA.
    Carvalho, F.
    Instituto Tecnológico e Nuclear, Sacavém, Portugal.
    Chapeyron, B.
    Crii-RAD, Valence, France.
    Cunha, I. L.
    IPEN-CNEN, Sao Paulo, Brazil.
    Dahlgaard, H.
    Risoe National Laboratory, Roskilde, Denmark.
    Galabov, N.
    National Institute of Meteorology and Hydrology, Pleven, Bulgaria.
    Fifield, L. K.
    Australian National University, Department of Nuclear Physics, Canberra, Australia.
    Gastaud, J.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Geering, J.-J.
    Institut de Radiophysique Appliquée, Lausanne, Switzerland.
    Gomez, I. F.
    Environmental Radiation Protection Department, Ciudad Habana, Cuba.
    Green, N.
    National Radiation Protection Board, Chilton, Oxon, UK.
    Hamilton, T.
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Ibanez, F. L.
    Universidad del Pais Vasco, Dept. de Ingeniera Nuclear y Mecanica de Fluidos, Bilbao, Spain.
    Ibn Majah, M.
    CNESTEN, Agdal, Rabat, Morocco.
    John, M.
    British NuclearFuels, Chemical and Metallurgical Service Department., Lancashire, UK.
    Kanisch, G.
    Federal Research Centre for Fisheries, Institute of Fisheries Ecology, Hamburg, Germany.
    Kenna, T. C.
    Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
    Kloster, M.
    Senatsverwaltung für Stadtentwicklung und Umweltshutz, Berlin, Germany.
    Korun, M.
    Nuclear Intitute “Jozef Stefan”, Ljubljana, Slovenia.
    Liong Wee Kwong, L.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    La Rosa, J.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Lee, S.-H.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Levy-Palomo, I.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Malatova, M.
    National Institute of Public Health, Praha, Czech Republic.
    Maruo, Y.
    JNC Tokai works, Health and Safety Division, Tokai-mura, Ibaraki, Japan.
    Mitchell, P.
    University College Dublin, Department of Experimental Physics, Dublin, Ireland.
    Murciano, I. V.
    Universite Politecnica de Barcelona, Instituto de Tecnicas Energeticas, Barcelona, Spain.
    Nelson, R.
    Bedford Institute of Oceanography, Department of Fisheries and Oceans, Dartmounth-N.S, Canada.
    Nouredine, A.
    Centre de Recherche Nucléaire d’Alger, Laboratoire des Etudes d’Impact Radiologique, Alger, Algeria.
    Oh, J.-S.
    Southampton Oceanography Centre, University of Southampton, Southampton, UK.
    Oregioni, B.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Le Petit, G.
    DASE/RCE, C.E.A., Bruyères-le-Châtel, France.
    Pettersson, Håkan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Reineking, A.
    Georg-August-Universitaet, Zentrales Isotopenlaboratorium, Goettingen, Germany.
    Smedley, P. A.
    CEFAS, Directorate of Fisheries Research, Lowestoft, Suffolk, UK.
    Suckow, A.
    Joint Geological Research Institute, Hannover, Germany.
    van der Struijs, T. D. B.
    RIKILT, Wageningen, The Netherlands.
    Voors, P. I.
    NRG, Petten, The Netherlands.
    Yoshimizu, K.
    Japan Chemical Analysis Centre, Chiba, Japan.
    Wyse, E.
    International Atomic Energy Agency, Marine Environment Laboratory, Monaco, & Comenius University, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia.
    Reference material for radionuclides in sediment. IAEA-384 (Fangataufa lagoon sediment).2007In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 273, no 2, p. 383-393Article in journal (Refereed)
    Abstract [en]

    A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides in the environment, as well as for the development and validation of analytical methods and for training purposes. The material is available from IAEA in 100 g units.

  • 215.
    Ragnehed, Mattias
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Pihlsgård, Johan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Wirell, Staffan
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Sökjer, Hannibal
    Linköping University, Department of Computer and Information Science, MDI - Interaction and Service Design Research Group. Linköping University, The Institute of Technology.
    Fägerstam, Patrik
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Jiang, Bo
    Linköping University, Department of Medical and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Visual Grading of 2D and 3D fMRI compared to image based descriptive measures2010In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 20, no 3, p. 714-724Article in journal (Refereed)
    Abstract [en]

    A prerequisite for successful clinical use of functional Magnetic Resonance Imaging (fMRI) is the selection of an appropriate imaging sequence. In this paper, 2D and 3D fMRI sequences were compared using different image quality assessment methods. Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from Visual Grading Characteristics (VGC) analysis of the fMRI results. It was found that significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results. In conclusion, in addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods.

  • 216.
    Ragnehed, Mattias
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Knutsson, Hans
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Axelsson Söderfeldt, Birgitta
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Restricted Canonical Correlation Analysis in Functional MRI-Validation and a Novel Thresholding Technique2009In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 29, no 1, p. 146-154Article in journal (Refereed)
    Abstract [en]

    Purpose: To validate the performance of an analysis method for fMRI data based on restricted canonical correlation analysis (rCCA) and adaptive filtering, and to increase the usability of the method by introducing a new technique for significance estimation of rCCA maps.

    Materials and Methods: Activation data from a language task and also a resting state fMRI data were collected from eight volunteers. Data was analyzed using both the rCCA method and the General Linear Model (GLM). A modified Receiver Operating Characteristic (ROC) method was used to evaluate the performance of the different analysis methods. The area under a fraction of the ROC curve was used as a measure of performance. On resting state data the fraction of voxels above certain significance thresholds were used to evaluate the significance estimation method.

    Results: The rCCA method scored significantly higher on the area under the ROC curve than the GLM. The fraction of activated voxels determined by thresholding according to the introduced significance estimation technique showed good agreement with the thresholds selected.

    Conclusion: The rCCA method is an effective analysis tool for fMRI data and its usability is increased with the introduced significance estimation method.

  • 217.
    Ragnehed, Mattias
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Linköping University, Faculty of Health Sciences.
    Engström, Maria
    Linköping University, Department of Medicine and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Linköping University, Department of Medicine and Health Sciences, Radiology. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping. Linköping University, Faculty of Health Sciences.
    Does diazepam influence the BOLD response?2007Conference paper (Other academic)
  • 218.
    Ragnehed, Mattias
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Håkansson, Irene
    Linköping University, Department of Neuroscience and Locomotion. Linköping University, Faculty of Health Sciences.
    Nilsson, Maritha
    National Board of Forensic Sciences, Linköping.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Söderfeldt, Birgitta
    Department of Clinical Science and Education, Sodersjukhuset, Karolinska Institutet, Stockholm, Sweden.
    Engström, Maria
    Linköping University, Department of Biomedical Engineering, Center for Medical Image Science and Visualization. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Influence of diazepam on clinically designed FMRI2007In: The Journal of Neuropsychiatry and Clinical Neurosciences, ISSN 0895-0172, E-ISSN 1545-7222, Vol. 19, no 2, p. 164-172Article in journal (Refereed)
    Abstract [en]

    The authors investigated the effect of diazepam on clinically relevant measures from functional magnetic resonance imaging (fMRI) examinations. Twenty volunteers were scanned twice. Using a double-blind randomized study design, the volunteers received placebo on one occasion, and on the other, 5 mg of diazepam. Three functional tests were used: motor, word generation, and working memory. Images were analyzed individually for each subject and the number of activated voxels and the laterality index were calculated. No significant effects related to the drug were detected. In contrast, the motor and working memory tasks showed a significant decrease in the number of activated voxels between Sessions 1 and 2, independently of diazepam administration. These results indicate that diazepam may be administered for premedication prior to fMRI investigations.

  • 219.
    Ragnehed, Mattias
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Linköping University, Faculty of Health Sciences.
    Philsgård, J
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiology. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping. Linköping University, Faculty of Health Sciences.
    Engström, Maria
    Linköping University, Department of Medicine and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Linköping University, Department of Medicine and Health Sciences, Radiology. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping. Linköping University, Faculty of Health Sciences.
    Using Visual Grading Characteristic for the evaluation of different fMRI data acquisition methods2008Conference paper (Other academic)
  • 220.
    Ressner, Marcus
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Disa
    Karolinska Institutet, Stockholm.
    Gustafsson, Agnetha
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Jonsson, Cathrine
    Karolinska universitetssjukhuset Solna, Stockholm.
    Experimental evaluation of iterative reconstruction for whole-body F-18 PET in a 3- and 4-ring PET/CT system2011Conference paper (Other academic)
  • 221.
    Romu, Thobias
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    MANA - Multi scale adaptive normalized averaging2011In: 2011 IEEE International Symposium on Biomedical Imaging: From Nano to Macro, IEEE conference proceedings, 2011, p. 361-364Conference paper (Refereed)
    Abstract [en]

    It is possible to correct intensity inhomogeneity in fat–water Magnetic Resonance Imaging (MRI) by estimating a bias field based on the observed intensities of voxels classified as the pure adipose tissue. The same procedure can also be used to quantify fat volume and its distribution which opens up for new medical applications. The bias field estimation method has to be robust since pure fat voxels are irregularly located and the density varies greatly within and between image volumes. This paper introduces Multi scale Adaptive Normalized Average (MANA) that solves this problem bybasing the estimate on a scale space of weighted averages. By usingthe local certainty of the data MANA preserves details where the local data certainty is high and provides realistic values in sparse areas.

  • 222.
    Romu, Thobias
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Forsgren, Mikael
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology and Gastroenterology UHL.
    Dahlström, Nils
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Kechagias, Stergios
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology and Gastroenterology UHL.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology and Gastroenterology UHL.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Fat Water Classification of Symmetrically Sampled Two-Point Dixon Images Using Biased Partial Volume Effects2011In: Proceedings of the annual meeting of the International Society for Magnetic Resonance in Medicine (ISMRM 2011), 2011., 2011Conference paper (Refereed)
  • 223.
    Romu, Thobias
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Robust fat-­‐water separation of symmetrically sampled two point Dixon data2012In: ISMRM workshop on Fat-­‐Water Separation: Insights, Applications & Progress in MRI, 2012Conference paper (Refereed)
  • 224.
    Romu, Thobias
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Elander, Louise
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    High resolution symmetrically sampled two point Dixon imaging2012In: Proceedings of the ISMRM Annual Meeting, 2012Conference paper (Other academic)
  • 225.
    Rydell, Joakim
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Johansson, Andreas
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Leinard, Olof Dahlqvist
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Farnebäck, Gunnar
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Health Sciences.
    Three Dimensional Phase Sensitive Reconstruction for Water/Fat Separation in MR Imaging using Inverse Gradient2008In: Proceedings of the International Society for Magnetic Resonance in Medicine annual meeting (ISMRM'08), 2008, p. 1519-Conference paper (Other academic)
    Abstract [en]

    Three dimensional phase sensitive reconstruction on two point Dixon volumes has been implemented with use of the inverse gradient. The results has beencompared with the inverse gradient method in two dimensions as well as with the well established region growing method proposed by Ma. The inversegradient method in 3D is able to unwrap the phase field in uncertain regions where the region growing method and the inverse gradient method in 2D cometo a stop.

  • 226.
    Rydell, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Knutsson, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Johansson, Andreas
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Borga, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    MRI Phase Unwrapping with Application to Water/Fat Separation2008In: Proceedings of the SSBA Symposium on Image Analysis,2008, 2008, p. 27-30Conference paper (Other academic)
  • 227.
    Rydell, Joakim
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Knutsson, Hans
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Pettersson, Johanna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Johansson, Andreas
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Farnebäck, Gunnar
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Phase Sensitive Reconstruction for Water/Fat Separation in MR Imaging Using Inverse Gradient2007In: Medical Image Computing and Computer-Assisted Intervention – MICCAI 2007. 10th International Conference, Brisbane, Australia, October 29 - November 2, 2007, Proceedings, Part I / [ed] Nicholas Ayache, Sebastien Ourselin and Anthony Maeder, Springer Berlin/Heidelberg, 2007, p. 210-218Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel method for phase unwrapping for phase sensitive reconstruction in MR imaging. The unwrapped phase is obtained by integrating the phase gradient by solving a Poisson equation. An efficient solver, which has been made publicly available, is used to solve the equation. The proposed method is demonstrated on a fat quantification MRI task that is a part of a prospective study of fat accumulation. The method is compared to a phase unwrapping method based on region growing. Results indicate that the proposed method provides more robust unwrapping. Unlike region growing methods, the proposed method is also straight-forward to implement in 3D.

  • 228.
    Salih, Isam
    et al.
    Linköping University, Department of Medicine and Care.
    Bäckström, Mattias
    Man-Technology-Environment Research Centre, Örebro University, Örebro, Sweden.
    Karlsson, Stefan
    Lund, Eva
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Impact of fluoride and other aquatic parameters on radon concentration in natural waters2004In: Journal of Applied Radiation & Isotopes, ISSN 0969-8043, Vol. 60, no 1, p. 99-104Article in journal (Refereed)
    Abstract [en]

    Radon (222Rn) accumulation in water in relation to stable elements was studied for the purpose of determining factors influencing the transfer of 222Rn to and from water. In 72 groundwater samples, 222Rn and about 70 analytical parameters were analysed using radiometric and ICP-MS techniques. Using multivariate statistics (partial least squares), it was observed that 222Rn has a positive correlation with fluoride and uranium. The correlation with fluoride was further investigated by a laboratory time-scale experiment to measure the emanation of 222Rn from water as a function of fluoride, pH and carbonate. The transfer of 222Rn from water was measured by continuous monitoring in air in a closed loop set-up. It was observed that fluoride in water adhere or trap 222Rn preferably in acidic water (pH 3). It is suspected that natural physical processes (such as diffusion and microbubble phenomenon) are less effective to transport 222Rn in the presence of fluoride.

  • 229.
    Salih, Isam M. Musa
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Radon in natural waters: Analytical Methods; Correlation to Environmental Parameters; Radiation Dose Estimation; and GIS Applications2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Investigations of radon in natural water and its relation to physical and chemical parameters are outlined in this thesis. In particular, a method for measuring 222Rn in water at low concentrations (~20 mBq.l-1) is described, followed by discussions concerning the design and its application to study both radon and parameters influencing radon levels in natural waters. A topic considered is the impact of fluoride and other aquatic parameters on radon in water. Moreover, variables such as uranium series radionuclides and stable elements in water, bedrock and sediment radioactivity and geology are investigated in two case studies. This was performed by employing radiometric-, chemical-, statistical- and GIS & geostatistical- analyses. The general water chemistry and presence of some elements such as fluoride was observed to influence radon levels in water. Health aspects of radon in drinking water are discussed based on radiation dose assessments. The radiation doses are compared with and added to doses incurred from ingestion of uranium, radium and polonium isotopes in drinking water and inhalation of radon in air in order to estimate total exposures for different age categories. The results may have a potential for future epidemiological studies.

    List of papers
    1. Determination of 222Rn and 226Ra in water using a large volume ionisation chamber
    Open this publication in new window or tab >>Determination of 222Rn and 226Ra in water using a large volume ionisation chamber
    2000 (English)In: Journal of Environmental Radioactivity, ISSN 0265-931X, Vol. 48, no 2, p. 235-245Article in journal (Refereed) Published
    Abstract [en]

    A new method for measuring 222Rn and 226Ra in water has been devised. It is based on exhaling radon to a void volume by continuous bubbling of air through the water. The exhaled radon is then transferred in a closed circuit to a modified radon gas pulse ionisation chamber for alpha-spectrometric measurements. About 86% of the radon in water is transferred from 0.75 l of water to the void volume (3.2 l). The set-up offers direct and specific 222Rn measurements for a wide range of concentrations and shows a low detection limit (LLD=45 mBq l−1 for 8 h counting time). Radium in water is measured, via radon, after sample storage for a month. The method was compared with gamma ray spectrometry for radon and for radium, the latter after pre-concentration by co-precipitation with MnO2 from 10 l water samples. An excellent agreement between the two techniques was obtained. As a part of a radon survey, the method was employed for analysis of drinking water from bedrock wells.

    Keywords
    Radon, Radium, Drinking water, Ground water, Measurement, Ionisation chamber
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-13698 (URN)10.1016/S0265-931X(99)00062-4 (DOI)
    Available from: 2003-12-18 Created: 2003-12-18 Last updated: 2009-08-20
    2. 222Rn in coastal waters: onboard analysis of 222Rn depth-profiles and evaluation of non-supported content
    Open this publication in new window or tab >>222Rn in coastal waters: onboard analysis of 222Rn depth-profiles and evaluation of non-supported content
    (English)Manuscript (Other academic)
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-13699 (URN)
    Note

    This paper will nog be published.

    Available from: 2003-12-18 Created: 2003-12-18 Last updated: 2017-01-11Bibliographically approved
    3. Impact of fluoride and other aquatic parameters on radon concentration in natural waters
    Open this publication in new window or tab >>Impact of fluoride and other aquatic parameters on radon concentration in natural waters
    Show others...
    2004 (English)In: Journal of Applied Radiation & Isotopes, ISSN 0969-8043, Vol. 60, no 1, p. 99-104Article in journal (Refereed) Published
    Abstract [en]

    Radon (222Rn) accumulation in water in relation to stable elements was studied for the purpose of determining factors influencing the transfer of 222Rn to and from water. In 72 groundwater samples, 222Rn and about 70 analytical parameters were analysed using radiometric and ICP-MS techniques. Using multivariate statistics (partial least squares), it was observed that 222Rn has a positive correlation with fluoride and uranium. The correlation with fluoride was further investigated by a laboratory time-scale experiment to measure the emanation of 222Rn from water as a function of fluoride, pH and carbonate. The transfer of 222Rn from water was measured by continuous monitoring in air in a closed loop set-up. It was observed that fluoride in water adhere or trap 222Rn preferably in acidic water (pH 3). It is suspected that natural physical processes (such as diffusion and microbubble phenomenon) are less effective to transport 222Rn in the presence of fluoride.

    Keywords
    Radon, Fluoride, Microbubble, Stable elements
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-13700 (URN)10.1016/j.apradiso.2003.10.007 (DOI)
    Available from: 2003-12-18 Created: 2003-12-18 Last updated: 2009-08-20
    4. Uranium and thorium series radionuclides in drinking water from drilled bedrock wells: correlation to geology and bedrock radioactivity and dose estimation
    Open this publication in new window or tab >>Uranium and thorium series radionuclides in drinking water from drilled bedrock wells: correlation to geology and bedrock radioactivity and dose estimation
    2002 (English)In: Radiation protection dosimetry, ISSN 0144-8420, Vol. 102, no 3, p. 249-258Article in journal (Refereed) Published
    Abstract [en]

    Natural radioactivity in drinking water from 328 drilled wells was studied in correlation to source parameters. Poor correlation to both aquifer geology and bedrock radioactivity was observed. Concentrations of 238U, 226Ra, 228Ra, 222Rn and 210Po in groundwater samples was in the ranges <0.027-5.3, <0.016-4.9, <0.014-1.24, 5-8105 and <0.05-0.947 Bq.l(-1) respectively. In about 80% of the sites the radon concentration exceeds the Nordic recommended exemption level for radon in drinking water and 15% of the sites exceed the action limit. The effective doses from ingestion were calculated and presented in association with geology. Doses due to ingestion ranged between 0.05 and 20.4 mSv.y(-1), where the average contribution from 222Rn amounted to 75%. In comparison, the effective doses from inhalation of indoor 222Rn ranged between 0.2 and 20 mSv.y(-1). The average contribution from inhalation of 222Rn in air to the total effective dose (ingestion+inhalation) was 58 +/- 22%, 73 +/- 18% and 77 +/- 16% (1 SD) for the age categories 1 y, 10 y and adults respectively.

    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-13701 (URN)
    Available from: 2003-12-18 Created: 2003-12-18 Last updated: 2009-08-20
    5. Spatial correlation between radon (222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical analyses
    Open this publication in new window or tab >>Spatial correlation between radon (222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical analyses
    2002 (English)In: Journal of Spatial Hydrology, ISSN 1530-4736, Vol. 2, no 2, p. 1-10Article in journal (Refereed) Published
    Abstract [en]

    This study describes approaches to create surface maps of radon in groundwater based on measurements of radon (222Rn) in drilled bedrock wells at unevenly distributed sites and uranium bedrock maps from the South East of Sweden, the Östergotland county (N 58°14’ – N 58°56’and E 14°53’ – E 16°06’), see figure 1. Geostatistical techniques of inverse distance weighted(IDW), kriging and cokriging were compared in terms of their interpolation power and correlation between the produced radon in the water layer and the bedrock uranium layer. The goal of these analyses and calculations is to improve our understanding concerning the factors influencing the transport of radon. Therefore, these interpolation techniques were investigated by optimizing parameters that are used in the specific interpolation. Using the IDW interpolator method at fixed radius enabled us to determine the linkage or search distances for auto correlation, and linkage between radon in water and bedrock. This method showed good agreement with the cokriging method when using uranium concentration as a secondary variable. Good interpolation layers (with least root mean square errors RMSE=232) were obtained by kriging. However, the kriged radon surface showed poor correlation with bedrock uranium layers. The best radon in waterlayer that match with uranium in bedrock layer was produced using IDW interpolator (RMSE=377, using all points). The correlation coefficient (R2) is 0.5 while for the kriging method the best correlation is R2 = 0.1. A compromise between the two approaches is demonstrated.

    Keywords
    radon, uranium, groundwater, bedrock, GIS, Kriging, IDW
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-13702 (URN)
    Available from: 2003-12-18 Created: 2003-12-18 Last updated: 2009-08-20
    6. Chemical character of drinking water from Swedish crystalline bedrock
    Open this publication in new window or tab >>Chemical character of drinking water from Swedish crystalline bedrock
    2003 (English)In: Environmental Monitoring, ISSN 0167-6369Article in journal (Refereed) Submitted
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13703 (URN)
    Available from: 2003-12-18 Created: 2003-12-18
  • 230.
    Salih, Isam
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Lund, Eva
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Determination of 222Rn and 226Ra in water using a large volume ionisation chamber2000In: Journal of Environmental Radioactivity, ISSN 0265-931X, Vol. 48, no 2, p. 235-245Article in journal (Refereed)
    Abstract [en]

    A new method for measuring 222Rn and 226Ra in water has been devised. It is based on exhaling radon to a void volume by continuous bubbling of air through the water. The exhaled radon is then transferred in a closed circuit to a modified radon gas pulse ionisation chamber for alpha-spectrometric measurements. About 86% of the radon in water is transferred from 0.75 l of water to the void volume (3.2 l). The set-up offers direct and specific 222Rn measurements for a wide range of concentrations and shows a low detection limit (LLD=45 mBq l−1 for 8 h counting time). Radium in water is measured, via radon, after sample storage for a month. The method was compared with gamma ray spectrometry for radon and for radium, the latter after pre-concentration by co-precipitation with MnO2 from 10 l water samples. An excellent agreement between the two techniques was obtained. As a part of a radon survey, the method was employed for analysis of drinking water from bedrock wells.

  • 231.
    Salih, Isam
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Lund, Eva
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Uranium and thorium series radionuclides in drinking water from drilled bedrock wells: correlation to geology and bedrock radioactivity and dose estimation2002In: Radiation protection dosimetry, ISSN 0144-8420, Vol. 102, no 3, p. 249-258Article in journal (Refereed)
    Abstract [en]

    Natural radioactivity in drinking water from 328 drilled wells was studied in correlation to source parameters. Poor correlation to both aquifer geology and bedrock radioactivity was observed. Concentrations of 238U, 226Ra, 228Ra, 222Rn and 210Po in groundwater samples was in the ranges <0.027-5.3, <0.016-4.9, <0.014-1.24, 5-8105 and <0.05-0.947 Bq.l(-1) respectively. In about 80% of the sites the radon concentration exceeds the Nordic recommended exemption level for radon in drinking water and 15% of the sites exceed the action limit. The effective doses from ingestion were calculated and presented in association with geology. Doses due to ingestion ranged between 0.05 and 20.4 mSv.y(-1), where the average contribution from 222Rn amounted to 75%. In comparison, the effective doses from inhalation of indoor 222Rn ranged between 0.2 and 20 mSv.y(-1). The average contribution from inhalation of 222Rn in air to the total effective dose (ingestion+inhalation) was 58 +/- 22%, 73 +/- 18% and 77 +/- 16% (1 SD) for the age categories 1 y, 10 y and adults respectively.

  • 232.
    Salih, Isam
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Sivertun, Åke
    Linköping University, Department of Computer and Information Science, GIS - Geographical Information Science Group. Linköping University, The Institute of Technology.
    Lund, Eva
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Spatial correlation between radon (222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical analyses2002In: Journal of Spatial Hydrology, ISSN 1530-4736, Vol. 2, no 2, p. 1-10Article in journal (Refereed)
    Abstract [en]

    This study describes approaches to create surface maps of radon in groundwater based on measurements of radon (222Rn) in drilled bedrock wells at unevenly distributed sites and uranium bedrock maps from the South East of Sweden, the Östergotland county (N 58°14’ – N 58°56’and E 14°53’ – E 16°06’), see figure 1. Geostatistical techniques of inverse distance weighted(IDW), kriging and cokriging were compared in terms of their interpolation power and correlation between the produced radon in the water layer and the bedrock uranium layer. The goal of these analyses and calculations is to improve our understanding concerning the factors influencing the transport of radon. Therefore, these interpolation techniques were investigated by optimizing parameters that are used in the specific interpolation. Using the IDW interpolator method at fixed radius enabled us to determine the linkage or search distances for auto correlation, and linkage between radon in water and bedrock. This method showed good agreement with the cokriging method when using uranium concentration as a secondary variable. Good interpolation layers (with least root mean square errors RMSE=232) were obtained by kriging. However, the kriged radon surface showed poor correlation with bedrock uranium layers. The best radon in waterlayer that match with uranium in bedrock layer was produced using IDW interpolator (RMSE=377, using all points). The correlation coefficient (R2) is 0.5 while for the kriging method the best correlation is R2 = 0.1. A compromise between the two approaches is demonstrated.

  • 233.
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Bildkvalitet vid projektionsradiografi2008In: Radiologi / [ed] Peter Aspelin, Holger Pettersson, lund: Studentlitteratur , 2008, 1, p. 35-49Chapter in book (Refereed)
    Abstract [sv]

    Radiologin är en av de kliniska specialiteter som växer snabbast och idag omfattar den klassisk röntgen, datortomografi, magnetkamera, nuklearmedicin, positronemissionstomografi och ultraljud. Den tekniska utvecklingen har inneburit att vi förutom att avbilda olika organs morfologi och funktion också kan avbilda skeenden på cellulär, molekylär och atomnivå och ersätta tvådimensionella bilder med tredimensionella och virtuella bilder. Radiologin kommer att spela en stor roll för den molekylära förståelsen av uppkomstmekanismen bakom sjukdomar. Den snabba digitala utvecklingen förenklar att kommunicera bilder och detta har gjort radiologin tillgänglig inte bara för radiologer utan även för ett stort antal medarbetare i vården. Denna lärobok vänder sig främst till medicine kandidater och läkare, men genom sin utformning, bl.a. det stora antalet bilder med kommentarer, kan den också användas av andra yrkeskategorier som är under utbildning eller verksamma inom sjukvården. Varje kapitel har skrivits av författare som utsetts av respektive subspecialitetsförening till Svensk Förening för Medicinsk Radiologi. Föreningen har subventionerat produktionen av boken så att så många som möjligt inom sjukvården ska ha möjlighet att införskaffa den. Till boken finns en omfattande webbplats med bokens röntgenmaterial som gjorts sökbart för läsaren. För att få tillgång till materialet krävs en aktiveringskod. I varje bok finns en unik kod som efter aktivering är förbrukad. För att säkerställa att du som köpare får denna kod, är boken inplastad. Webbplatsen blir klar sista veckan i augusti.

  • 234.
    Sandborg, Michael
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Comparison between Lucite and Water as a phantom material in medical radiology1990In: Progress in nuclear energy (New series), ISSN 0149-1970, E-ISSN 1878-4224, Vol. 24, no 1-3, p. 355-364Article in journal (Refereed)
    Abstract [en]

    In quality assurance and quality control programs in medical radiology, Lucite (i.e. plexiglas, perspex polymethyl methacrylate (PMMA)) phantoms are often used, for convenience, instead of water to imitate the patient's body. Since Lucite has higher density and lower average atomic number than water, the energy absorption and particularly photon scattering characteristics differ. A comparison is made between water, soft tissue and Lucite phantoms of the same linear dimensions with respect to photon energy absorption and scattering at photon energies between 1 and 150 keV. Analog Monte Carlo methods are used to simulate the photon transport within phantom and receptor. Charged particle equilibrium is assumed since the electron transport is not simulated (kerma approximation). It is also assumed that coherent scattering occurs independently with the atoms of the compounds. The results show that the scatter-to-primary ratio, S/P, of the energy imparted to the receptor, with the receptior located on the rear side of the phantom, is significantly larger with the Lucite than with the water or soft tissue phantom. Also, the single-event distribution of the energy imparted to the receptor by the scattered photons transmitted through the phantom, differs between Lucite and water. The fraction of incident energy imparted to the phantom is at low photon energies (below 80 keV) lower in Lucite than in water. The opposite is true at energies above 80 keV where Compton scattering predominates, and the higher density of Lucite is decisive

  • 235.
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Erbium filter in diagnostic radiology: calculations of contrast and patient mean ab­sorbed dose1989In: Optimisation of image quality and patient exposure: Proceedings of a Workshop organized jointly by the Commission of the European Communities and the Nationa lRadiological Protection Board / [ed] B. M. Moores, Β. F. Wall, Η. Eriskat and Η. Schibilla, London: British Institute of Radiology , 1989, p. 169-170Conference paper (Refereed)
    Abstract [en]

    Rare earth materials instead of aluminium as added filter have been reported to reduce the mean absorbed dose in the patient. With these filters, the energy spectrum can be shaped to yield high energy absorption in the detector (film or screen). Exchange of filter results in a change in contrast. The image contrast and the mean absorbed dose in the patient have been investigated in the case of detection of a small contrast detail in a homogeneous phantom. Image contrast is defined as the difference in optical densities on the film, behind and beside a small contrasting detail. The Monte Carlo photon transport technique has been used to calculate the mean absorbed dose in the phantom and the energy imparted to various intensifying screens. Different Xray spectra were obtained by varying tube potential and filter thickness as well as filter material. Using the image contrast as the image quality parameter, the optimization condition is to find that combination of tube potential, filter material and filter thickness that gives the lowest mean absorbed dose in the patient for a given contrast. The mean absorbed dose in a 2(H) mm thick water phantom is reduced by 1025% using an erbium filter at a tube potential which will give the same primary contrast as obtained with a 2 mm aluminium filter. Contrast equivalent tube potential, kVcq, is achieved at higher values than with a non ACcdgc filter like copper. With the same increase in tube load, the dose reduction using an erbium filter (130 mg/cm") is approximately as high as with a copper filter (200 mg/cm2). Dose reduction at equal contrast and filmblackening as with 2 mm aluminium added filter is higher at lower tube potentials. When the high atomic number of the detector material is at least ten below that of the filter, it is slightly favourable to dose reduction. The change in image contrast when exchanging the aluminium filter for one of erbium requires a change in tube potential to restore the contrast. This can be achieved with a decrease in patient mean absorbed dose at the expense of an approximate increase of two in tube load using 130 mg/cm" erbium as the added filter.

  • 236.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Alm Carlsson, Gudrun
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Influence on X-ray energy spectrum, contrasting detail and detector on the signal-to-noise ratio (SNR) and detective quantum efficiency (DQE) in projection radiography1992In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 7, no 6, p. 1245-1263Article in journal (Refereed)
    Abstract [en]

    A lower limit to patient irradiation in diagnostic radiology is set by the fundamental stochastics of the energy imparted to the image receptor (quantum noise). Image quality is investigated and expressed in terms of the signal-to-noise ratio due to quantum noise. The Monte Carlo method is used to calculate signal-to-noise ratios (SNRDelta S) and detective quantum efficiencies (DQEDelta S) in imaging thin contrasting details of air, fat, bone and iodine within a water phantom using X-ray spectra (40-140 kV) and detectors of CsI, BaFCl and Gd2O2S. The atomic composition of the contrasting detail influences considerably the values of SNRDelta S due to the different modulations of the energy spectra of primary photons passing beside and through the contrasting detail. By matching the absorption edges of the contrasting detail and the detector, a partially absorbing detector may be more efficient (yield higher SNRDelta S) than a totally absorbing one; this is demonstrated for the case of detecting an iodine detail using a CsI detector. The degradation of SNRDelta S and DQEDelta S due to scatter is larger when the detector is operated in the photon counting compared to in the energy integrating mode and for partially absorbing compared to totally absorbing detectors.

  • 237.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Carlsson, Carl
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Choice of optimal energy spectra in diagnostic radiology: an analysis based on calcu­lated signal-to-noise ratios in clinical, partially absorbing detectors1989In: British Institute of Radiology, Report 20, London: British Institute of Radiology, , 1989, p. 141-143Conference paper (Refereed)
  • 238.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Dance, David
    n/a.
    Comparison of different materials for test phantoms in diagnostic radiology1993In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 49, no 1, p. 345-347Article in journal (Refereed)
    Abstract [en]

    The use of test phantoms in diagnostic radiology is a well established practice in image quality control. Here Monte Carlo methods are used for comparing different phantom materials (water, Lucite, polystyrene, paraffin wax, Mylar, Mix-D, M3, Alderson muscle B and A-150) relative to soft tissue with regard to different physical quantities such as contrast and mean absorbed dose in the phantom. The results for each material are derived as the equivalent thicknesses resulting in the same value of the quantity of interest as a soft tissue phantom of a given thickness, this being varied between 5 and 25 cm. The phantom material yielding the smallest spread of equivalent thicknesses is regarded as the most soft tissue equivalent one. Water, Mix-D and M3 are the materials most equivalent to soft tissue of the phantom materials tested. Paraffin wax, polystyrene and Lucite show a larger spread in equivalent thicknesses.

  • 239.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Carlsson, C. A.
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Shaping X-ray spectra with filters in X-ray diagnostics1994In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 32, no 4, p. 384-390Article in journal (Refereed)
    Abstract [en]

    The influence on image contrast, tube load and patient mean absorbed dose of different ways of shaping diagnostic X-ray spectra by placing filters in the beam is derived for two radiographic models (abdominal screen-film radiography and intra-oral, dental radiography) using a computational model. The filters are compared at either equal tube load (keeping tube potential constant) or equal contrast (adjusting the tube potential with the different filters), but always at equal energy imparted per unit area to the image receptor. Compared at equal tube load and relative to standard aluminium filtration, reductions in the mean absorbed dose in the patient of 15–25% can be achieved using filters of Cu, Ti, W and Au (increasing the tube load by 30–40% compared with standard aluminium filtration). However, contrast is also reduced by 7%. Compared at equal contrast, the dose reductions are smaller, about 10%. Filters of copper are generally recommended, as are filters of aluminium. The use of bandpass filters (K-edge filters) should be restricted to examinations where the need for substantial variation in tube potential from patient to patient is small. The benefit of using thicker filters than those commonly used today (increasing tube load by factors of 1.4–2.0 compared with no added filter) is small as the dose reduction is most rapid for small initial values of added filters, and the increase in tube load increases steadily with increasing filter thickness.

  • 240.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Christoffersson, Jan-Ove
    n/a.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Almen, Torsten
    n/a.
    Dunce, D A
    n/a.
    The physical performance of different x-ray contrast agents: calculations using a Monte Carlo model of the imaging chain1995In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 40, no 7, p. 1209-1224Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo computational model of the imaging chain has been used to investigate the performance of X-ray contrast agents with atomic number, Z, 53<or=Z<or=90 with respect to physical image quality descriptors (contrast and signal to noise ratio, SNR) and patient mean absorbed dose. Contrast agents of equal molar concentrations were used within a water slab (simulating the patient). The imaging conditions were chosen to represent adult and paediatric examinations. For all tube potentials studied (40-140 kV), the contrast agents with the highest atomic numbers (bismuth and thorium) gave the highest contrast. In analogue screen-film imaging, several other contrast agents could produce a higher image contrast than iodine in a limited range of tube potentials. This advantage could alternatively be effected as a reduced amount of administered contrast agent, or as a reduced mean absorbed dose in the patient. In digital imaging, a lower mean absorbed dose for a constant SNR than that with iodine can be achieved for ranges of tube potentials and contrast agents. Bismuth and thorium yield a lower dose than iodine at all studied tube potentials. Gadolinium and erbium could alternatively be used at a broad range of tube potentials above 90 kV with a dose penalty of only 5-20%.

  • 241.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    n/a.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Monte Carlo study of grid performance in diagnostic radiology: factors which affect the selection of tube potential and grid ratio1993In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 66, p. 1164-1176Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo computational model has been developed for the study of the performance of anti-scatter grids in diagnostic radiology. It is used here to estimate the scatter in the image plane from soft tissue phantoms (representing the patient) and to calculate image contrast and the mean absorbed dose in the phantom. Different scattering conditions, representative of various examinations, have been investigated: adult lumbar spine; small field radiography and fluoroscopy; adult chest and paediatric pelvis and chest. For each scattering condition, the combinations of tube potential and grid ratio have been found which, for a well designed grid, result in the lowest mean absorbed dose in the phantom for a fixed contrast level. In examinations which generate large amounts of scatter, the use of high grid ratios in combination with high tube potentials is favourable with regard to both mean absorbed dose in the phantom and tube charge. When less scatter is generated, either the grid ratio or the tube potential can be varied to achieve the desired contrast level. High grid ratios require shorter exposure times, but need careful alignment in the beam to prevent primary radiation cut-off. It is shown that the air gap technique can be used to reduce patient dose in examinations with small amounts of scatter, but in combinations with a lower tube potential than when a grid is used.

  • 242.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    The Royal Marsden Hospital.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Monte Carlo study of grid performance in diagnostic radiology: task dependent opti­misation for screen-film imaging1994In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 67, p. 76-85Article in journal (Refereed)
    Abstract [en]

    An optimization of anti-scatter grid design using Monte Carlo techniques in diagnostic radiology is presented. The criterion for optimization was to find the combinations of the grid parameters (lead strip width, grid ratio and strip density) and tube potential which result in the lowest mean absorbed dose in the patient at fixed image contrast. The optimization was performed in three irradiation geometries, representing different scattering conditions (paediatric examinations, and two adult lumbar spine examinations) and was restricted to grids using fibre materials in covers and interspaces. Grid designs currently available were studied, as were designs which use thinner strips (< 30 µm) and higher grid ratios (> 18). It was found that grids with widely different strip densities (strips cm–1) and grid ratios can have good performance provided that they are used with appropriate strip width and tube potential. With increasing amounts of scatter, the optimal grid requires thicker strips and higher grid ratios. Increasing the strip density and using thinner strips and higher grid ratios are generally required. Grids with low strip density (25 strips cm–1) were found to be less sensitive to alterations in strip width. Optimal grids for paediatric radiology require thinner strips (10–20 µm) than those in currently available grids. Grids on the market are best suited for examinations of the adult body in anteroposterior (AP) view. In the adult lateral view, representing the largest scattering volume, higher grid ratios (> 18) than those in existing grids would be optimal. Examples of good grid designs are given for each examination.

  • 243.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    n/a.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Results from an optimisation of grid design in diagnostic radiology1995In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 57, no 1, p. 211-215Article in journal (Refereed)
    Abstract [en]

    Results of an optimisation of grid design using a Monte Carlo model of the imaging chain are presented. Patient dose is significantly reduced by changing from aluminium to fibre grid covers and interspaces while keeping contrast constant. Numerous commercial grids have been investigated to identify superior designs. For optimal use, grids with high strip density require thinner lead strips and higher ratios than grids with low strip density. In paediatric radiology, grids with very thin strips (10-20 µm), or an air gap can be considered. In an adult lumbar spine examination, the optimal grid ratios are higher (greater than 15) than in commercial grids. This is particularly accentuated for grids with high strip density, fibre interspaces and in the lateral view. For a given imaging task, it is possible to identify grids of different design that have good performance, provided an appropriate strip width and tube potential are selected.

  • 244.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    n/a.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Selection of anti-scatter grids for different imaging tasks: the advantage of low atomic number cover and interspace materials1993In: British Journal of Radiology, ISSN 0007-1285, E-ISSN 1748-880X, Vol. 66, p. 1151-1163Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo computer program has been developed for the study of anti-scatter grids used in diagnostic radiology. The program estimates the scatter from soft tissue phantoms representative of either adult or paediatric examinations and uses dose increase, signal-to-noise ratio improvement and contrast improvement factors to study grid performance. It has been used to quantify the advantage of replacing grids with aluminium covers and interspaces by grids using materials of low atomic number for these components. Two approaches are used. First, the aluminium and low atomic number alternatives are compared for five grid ratios at fixed strip density and width and for tube potentials of 50, 70, 100 and 150 kV. Second, 44 commercially available grids are compared for three different imaging situations (lumbar spine, chest and paediatric). The results demonstrate that grids made with carbon fibre cover and cotton fibre interspace result in greater improvements in contrast and signal-to-noise ratio, and lower dose increase factors, than do grids made with aluminium. The dose reduction varies with irradiation conditions and is generally larger at lower tube potentials, higher grid ratios and lower strip densities. A typical reduction in mean absorbed dose in the patient is 30% in an adult lumbar spine (AP view) at 70 kV with a grid with 36 strips per centimetre and ratio 12.

  • 245.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    n/a.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Tapiovaara, Markku
    n/a.
    A Monte Carlo study of grid performance in diagnostic radiology: task-dependent opti­mization for digital imaging 1994In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 39, no 10, p. 1659-1676Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo computational model has been used to optimize grid design in digital radiography. The optimization strategy involved finding grid designs that, for a constant signal-to-noise ratio, resulted in the lowest mean absorbed dose in the patient. Different examinations were simulated to explore the dependence of the optimal scatter-rejection technique on the imaging situation. A large range of grid designs was studied, including grids with both aluminium and fibre interspaces and covers, and compared to a 20 cm air gap. The results show that the optimal tube potential in each examination does not depend strongly on the scatter-rejection technique. There is a significant dose reduction associated with the use of fibre-interspaced grids, particularly in paediatric radiography. The optimal grid ratio and strip width increase with increasing scattering volume. With increasing strip density, the optimal strip width decreases, and the optimal grid ratio increases. Optimal grid ratios are higher than those used today, particularly for grids with large strip density. It is, however, possible to identify grids of good performance for a range of strip densities and grid ratios provided the strip width is selected accordingly. The computational method has been validated by comparison with measurements with a caesium iodide image receptor.

  • 246.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dance, David
    The Royal Marsden Hospital.
    Persliden, Jan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    A Monte Carlo program for the calculation of contrast, noise and absorbed dose in diagnostic radiology1994In: Computer Methods and Programs in Biomedicine, ISSN 0169-2607, E-ISSN 1872-7565, Vol. 42, no 3, p. 167-180Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo computer program has been developed for the simulation of X-ray photon transport in diagnostic X-ray examinations. The simulation takes account of the incident photon energy spectrum and includes a phantom (representing the patient), an anti-scatter grid and an image receptor. The primary objective for developing the program was to study and optimise the design of anti-scatter grids. The program estimates image quality in terms of contrast and signal-to-noise ratio, and radiation risk in terms of mean absorbed dose in the patient. It therefore serves as a tool for the optimisation of the radiographic procedure. A description is given of the program and the variance-reduction techniques used. The computational method was validated by comparison with measurements and other Monte Carlo simulations.

  • 247.
    Sandborg, Michael
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Nilsson Althen, Jonas
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Agneta
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    EFFICIENT QUALITY ASSURANCE PROGRAMS IN RADIOLOGY AND NUCLEAR MEDICINE IN ÖSTERGÖTLAND, SWEDEN2010In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 139, no 1-3, p. 410-417Article in journal (Refereed)
    Abstract [en]

    Owners of imaging modalities using ionising radiation should have a documented quality assurance (QA) program, as well as methods to justify new radiological procedures to ensure safe operation and adequate clinical image quality. This includes having a system for correcting divergences, written imaging protocols, assessment of patient and staff absorbed doses and a documented education and training program. In this work, how some aspects on QA have been implemented in the County of Östergötland in Sweden, and efforts to standardise and automate the process as an integrated part of the radiology and nuclear medicine QA programs were reviewed. Some key performance parameters have been identified by a Swedish task group of medical physicists to give guidance on selecting relevant QA methods. These include low-contrast resolution, image homogeneity, automatic exposure control, calibration of air kerma-area product metres and patient–dose data registration in the radiological information system, as well as the quality of reading stations and of the transfer of images to the picture archive and communication system. IT-driven methods to automatically assess patient doses and other data on all examinations are being developed and evaluated as well as routines to assess clinical image quality by use of European quality criteria. By assessing both patient absorbed doses and clinical image quality on a routine basis, the medical physicists in our region aim to be able to spend more time on imaging optimisation and less time on periodic testing of the technical performance of the equipment, particularly on aspects that show very few divergences. The role of the Medical Physics Expert is rapidly developing towards a person doing advanced data-analysis and giving scientific support rather than one performing mainly routine periodic measurements. It is concluded that both the European Council directive and the rapid development towards more complex diagnostic imaging systems and procedures support this changing role of the medical physics professional.

  • 248.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Nilsson Althen, Jonas
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Gustafsson, Agnetha
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Efficient quality assurance in radiology and Nuclear Medicine2010Conference paper (Other academic)
  • 249.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Nilsson Althén, Jonas
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Pettersson, Håkan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Rossitti, Sandro
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Patient Organ Radiation Doses During Treatment for Aneurysmal Subarachnoid Hemorrhage2012In: Clinical neuroradiology, ISSN 1869-1447, Vol. 22, no 4, p. 315-325Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The aim of this retrospective study was to estimate risk organ doses and to estimate radiation risks during the imaging work-up and treatment for aneurysmal subarachnoid hemorrhage (SAH). METHODS: The imaging procedures comprised computed tomography and digital subtraction angiography studies for diagnosis or endovascular interventional procedures in 50 consecutive patients. Equivalent organ doses (H(T)) to skin, brain, eye lens, salivary glands, thyroid and oral mucosa were measured using thermoluminescence dosimeters in an anthropomorphic head phantom. Picture archiving and communication system (PACS) and radiological information system (RIS) records were analyzed and the frequency of each imaging procedure was recorded as well as the registered individual kerma-length product (P(KL)) and the kerma-area product (P(KA)). The doses were computed by multiplying the recorded P(KL) and P(KA) values by the conversion coefficients H(T)/P(KL) and H(T)/P(KA) from the head phantom. RESULTS: The mean fluoroscopy time, P(KL) and P(KA) were 38 min, 7269 mGy cm and 286 Gy cm(2), respectively. The estimated mean equivalent doses were as follows: skin 2.51 Sv, brain 0.92 Sv, eye lens 0.43 Sv and salivary glands 0.23 Sv. Maximum organ doses were 2.3-3.5 times higher than the mean. Interventional procedures contributed 66 % to skin dose, 55 % to brain dose and 25 % to eye lens dose. Of the patients with an estimated skin dose exceeding 6 Sv, only 1 developed temporary epilation. CONCLUSION: The risk for radiation-induced cancer for SAH patients is low (2-3 cases per 1,000 patients, of which 90 % are expected to be benign types) compared with the risk of tissue reactions on the head such as skin erythema and epilation (1 temporary epilation per 50 patients).

  • 250.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Rossitti, Sandro
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Local skin and eye lens equivalent odses in interventional neuroradiology2010In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 20, no 3, p. 725-733Article in journal (Refereed)
    Abstract [en]

    Purpose  To assess patient skin and eye lens doses in interventional neuroradiology and to assess both stochastic and deterministic radiation risks. Methods  Kerma–area product (P KA) was recorded and skin doses measured using thermoluminescence dosimeters. Estimated dose at interventional reference point (IRP) was compared with measured absorbed doses. Results  The average and maximum fluoroscopy times were 32 and 189 min for coiling and 40 and 144 min for embolisation. The average and maximum P KA for coiling were 121 and 436 Gy cm2, respectively, and 189 and 677 Gy cm2 for embolisation. The average and maximum values of the measured maximum absorbed skin doses were 0.72 and 3.0 Sv, respectively, for coiling and 0.79 and 2.1 Sv for embolisation. Two out of the 52 patients received skin doses in excess of 2 Sv. The average and maximum doses to the eye lens (left eye) were 51 and 515 mSv (coiling) and 71 and 289 mSv (embolisation). Conclusion  The ratio between the measured dose and the dose at the IRP was 0.44 ± 0.18 mSv/mGy indicating that the dose displayed by the x-ray unit overestimates the maximum skin dose but is still a valuable indication of the dose. The risk of inducing skin erythema and lens cataract during our hospital procedures is therefore small.

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