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Söderberg, Jonas
Publications (10 of 12) Show all publications
Söderberg, J. (2007). Dosimetry and radiation quality in fast-neutron radiation therapy: A study of radiation quality and basic dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections. (Doctoral dissertation). Institutionen för medicin och vård
Open this publication in new window or tab >>Dosimetry and radiation quality in fast-neutron radiation therapy: A study of radiation quality and basic dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The dosimetric properties of fast-neutron beams with energies ≤80 MeV were explored using Monte Carlo techniques. Taking into account transport of all relevant types of released charged particles (electrons, protons, deuterons, tritons, 3He and α particles) pencil-beam dose distributions were derived and used to calculate absorbed dose distributions. Broad-beam depth doses in phantoms of different materials were calculated and compared and the scaling factors required for converting absorbed dose in one material to absorbed dose in another derived. The scaling factors were in good agreement with available published data and show that water is a good substitute for soft tissue even at neutron energies as high as 80 MeV. The inherent penumbra and the fraction of absorbed dose due to photon interactions were also studied, and found to be consistent with measured values reported in the literature.

Treatment planning in fast-neutron therapy is commonly performed using dose calculation algorithms designed for photon beam therapy. When applied to neutron beams, these algorithms have limitations arising from the physical models used. Monte Carlo derived neutron pencil-beam kernels were parameterized and implemented in the photon dose calculation algorithms of the TMS (MDS Nordion) treatment planning system. It was shown that these algorithms yield good results in homogeneous water media. However, the method used to calculate heterogeneity corrections in the photon dose calculation algorithm did not yield correct results for neutron beams in heterogeneous media.

To achieve results with adequate accuracy using Monte Carlo simulations, fundamental cross-section data are needed. Neutron cross-sections are still not sufficiently well known. At the The Svedberg Laboratory in Uppsala, Sweden, an experimental facility has been designed to measure neutron-induced charged-particle production cross-sections for (n,xp), (n,xd), (n,xt), (n,x3He) and (n,xα) reactions at neutron energies up to 100 MeV. Depending on neutron energy, these generated particles account for up to 90% of the absorbed dose. In experimental determination of the cross-sections, measured data have to be corrected for the energies lost by the charged particles before leaving the target in which they were generated. To correct for the energy-losses, a computational code (CRAWL) was developed. It uses a stripping method. With the limitation of reduced energy resolution, spectra derived using CRAWL compares well with those derived using other methods.

In fast-neutron therapy, the relative biological effectiveness (RBE) varies from 1.5 to 5, depending on neutron energy, dose level and biological end-point. LET and other physical quantities, developed within the field of microdosimetry over the past couple of decades, have been used to describe RBE variations between different fast-neutron beams as well as within a neutron irradiated body. In this work, a Monte Carlo code (SHIELD-HIT) capable of transporting all charged particles contributing to absorbed dose, was used to calculate energy-differential charged particle spectra. Using these spectra, values of the RBE related quantities LD, γD, γ* and R were derived and studied as function of neutron energy, phantom material and position in a phantom. Reasonable agreement with measured data in the literature was found and indicates that the quantities may be used to predict RBE variations in an arbitrary fast-neutron beam.

Place, publisher, year, edition, pages
Institutionen för medicin och vård, 2007
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 989
Keywords
Neutron, Dosimetry, Radiotherapy, Monte Carlo, Microdosimetry, Cross-section, RBE, LET, Energy-loss corrections
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-8589 (URN)978-91-85715-37-4 (ISBN)
Public defence
2007-04-04, Conrad, Röntgenavdelningen, Campus US, Linköpings Universitet, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2007-03-22 Created: 2007-03-22 Last updated: 2015-03-20
Grindborg, J.-E., Lillhok, J., Lindborg, L., Gudowska, I., Söderberg, J., Carlsson, G. & Nikjoo, H. (2007). Nanodosimetric measurements and calculations in a neutron therapy beam. Radiation Protection Dosimetry, 126(1-4), 463-466
Open this publication in new window or tab >>Nanodosimetric measurements and calculations in a neutron therapy beam
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2007 (English)In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 126, no 1-4, p. 463-466Article in journal (Refereed) Published
Abstract [en]

A comparison of calculated and measured values of the dose mean lineal energy (yD) for the former neutron therapy beam at Louvain-la-Neuve is reported. The measurements were made with wall-less tissue-equivalent proportional counters using the variance-covariance method and simulating spheres with diameters between 10 nm and 15 µm. The calculated yD-values were obtained from simulated energy distributions of neutrons and charged particles inside an A-150 phantom and from published yD-values for mono-energetic ions. The energy distributions of charged particles up to oxygen were determined with the SHIELD-HIT code using an MCNPX simulated neutron spectrum as an input. The mono-energetic ion yD-values in the range 3-100 nm were taken from track-structure simulations in water vapour done with PITS/KURBUC. The large influence on the dose mean lineal energy from the light ion (A > 4) absorbed dose fraction, may explain an observed difference between experiment and calculation. The latter being larger than earlier reported result. Below 50 nm, the experimental values increase while the calculated decrease. © The Author 2007. Published by Oxford University Press. All rights reserved.

National Category
Social Sciences
Identifiers
urn:nbn:se:liu:diva-47433 (URN)10.1093/rpd/ncm093 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Lillhök, J. E., Grindborg, J.-E., Lindborg, L., Gudowska, I., Alm-Carlsson, G., Söderberg, J., . . . Medin, J. (2007). Nanodosimetry in a clinical neutron therapy beam using the variance-covariance method and Monte Carlo simulations. Physics in Medicine and Biology, 52(16), 4953-4966
Open this publication in new window or tab >>Nanodosimetry in a clinical neutron therapy beam using the variance-covariance method and Monte Carlo simulations
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2007 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 52, no 16, p. 4953-4966Article in journal (Refereed) Published
Abstract [en]

Nanodosimetric single-event distributions or their mean values may contribute to a better understanding of how radiation induced biological damages are produced. They may also provide means for radiation quality characterization in therapy beams. Experimental nanodosimetry is however technically challenging and Monte Carlo simulations are valuable as a complementary tool for such investigations. The dose-mean lineal energy was determined in a therapeutic p(65)+Be neutron beam and in a 60Co γ beam using low-pressure gas detectors and the variance-covariance method. The neutron beam was simulated using the condensed history Monte Carlo codes MCNPX and SHIELD-HIT. The dose-mean lineal energy was calculated using the simulated dose and fluence spectra together with published data from track-structure simulations. A comparison between simulated and measured results revealed some systematic differences and different dependencies on the simulated object size. The results show that both experimental and theoretical approaches are needed for an accurate dosimetry in the nanometer region. In line with previously reported results, the dose-mean lineal energy determined at 10 nm was shown to be related to clinical RBE values in the neutron beam and in a simulated 175 MeV proton beam as well. © 2007 IOP Publishing Ltd.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-38796 (URN)10.1088/0031-9155/52/16/016 (DOI)45672 (Local ID)45672 (Archive number)45672 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Söderberg, J., Alm Carlsson, G. & Ahnesjö, A. (2003). Monte Carlo evaluation of a photon pencil kernel algorithm applied to fast neutron therapy treatment planning. Physics in Medicine and Biology, 48(20), 3327-3344
Open this publication in new window or tab >>Monte Carlo evaluation of a photon pencil kernel algorithm applied to fast neutron therapy treatment planning
2003 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, Vol. 48, no 20, p. 3327-3344Article in journal (Refereed) Published
Abstract [en]

When dedicated software is lacking, treatment planning for fast neutron therapy is sometimes performed using dose calculation algorithms designed for photon beam therapy. In this work Monte Carlo derived neutron pencil kernels in water were parametrized using the photon dose algorithm implemented in the Nucletron TMS (treatment management system) treatment planning system. A rectangular fast-neutron fluence spectrum with energies 0–40 MeV (resembling a polyethylene filtered p(41)+ Be spectrum) was used. Central axis depth doses and lateral dose distributions were calculated and compared with the corresponding dose distributions from Monte Carlo calculations for homogeneous water and heterogeneous slab phantoms. All absorbed doses were normalized to the reference dose at 10 cm depth for a field of radius 5.6 cm in a 30 × 40 × 20 cm3 water test phantom. Agreement to within 7% was found in both the lateral and the depth dose distributions. The deviations could be explained as due to differences in size between the test phantom and that used in deriving the pencil kernel (radius 200 cm, thickness 50 cm). In the heterogeneous phantom, the TMS, with a directly applied neutron pencil kernel, and Monte Carlo calculated absorbed doses agree approximately for muscle but show large deviations for media such as adipose or bone. For the latter media, agreement was substantially improved by correcting the absorbed doses calculated in TMS with the neutron kerma factor ratio and the stopping power ratio between tissue and water. The multipurpose Monte Carlo code FLUKA was used both in calculating the pencil kernel and in direct calculations of absorbed dose in the phantom.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14361 (URN)10.1088/0031-9155/48/20/005 (DOI)
Available from: 2007-03-22 Created: 2007-03-22 Last updated: 2015-03-20
Söderberg, J., Dangtip, S., Alm Carlsson, G. & Olsson, N. (2002). Correction of measured charged-particle spectra for energy losses in the target: A comparison of three methods. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 195(3-4), 426-434
Open this publication in new window or tab >>Correction of measured charged-particle spectra for energy losses in the target: A comparison of three methods
2002 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 195, no 3-4, p. 426-434Article in journal (Refereed) Published
Abstract [en]

The experimental facility, MEDLEY, at the The Svedberg Laboratory in Uppsala, has been constructed to measure neutron-induced charged-particle production cross-sections for (n, xp), (n, xd), (n, xt), (n, x3He) and (n, xα) reactions at neutron energies up to 100 MeV. Corrections for the energy loss of the charged particles in the target are needed in these measurements, as well as for loss of particles. Different approaches have been used in the literature to solve this problem. In this work, a stripping method is developed, which is compared with other methods developed by Rezentes et al. and Slypen et al. The results obtained using the three codes are similar and they could all be used for correction of experimental charged-particle spectra. Statistical fluctuations in the measured spectra cause problems independent of the applied technique, but the way to handle it differs in the three codes.

Keywords
Neutron, Cross-section, Charged particle, Energy-loss corrections
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14359 (URN)10.1016/S0168-583X(02)01090-X (DOI)000178915500023 ()
Available from: 2007-03-22 Created: 2007-03-22 Last updated: 2017-12-13
Söderberg, J. & Pettersson, H. (2002). Katastrofer orsakade av joniserande strålning (2ed.). In: Sten Lennquist (Ed.), Katastrofmedicin: (pp. 303-318). Linköping: Linköpings universitet
Open this publication in new window or tab >>Katastrofer orsakade av joniserande strålning
2002 (Swedish)In: Katastrofmedicin / [ed] Sten Lennquist, Linköping: Linköpings universitet , 2002, 2, p. 303-318Chapter in book (Other academic)
Abstract [sv]

Denna bok beskriver hur man ska hantera den svåra uppgiften att bedriva sjukvård på effektivast möjliga sätt i alla de olika typer av situationer där det akuta vårdbehovet överstiger vad som kan klaras med tillgängliga resurser. Den täcker hela omhändertagandekedjan från skadeområdet till definitiv behandling på sjukhus. Denna nya upplaga av Katastrofmedicin är en helt ny bok, utökad till innehållet och uppdaterad mot bakgrund av den omfattande utveckling som präglat detta ämnesområde sedan föregående upplaga.

Katastrofmedicin kan användas som både läromedel vid utbildning på alla nivåer och som en lättillgänglig handbok och vänder sig till såväl personal i prehospital vård som till läkare och sjuksköterskor på sjukhusens akutmottagningar och inom berörda specialiteter.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2002 Edition: 2
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27586 (URN)12249 (Local ID)91-47-04856-5 (ISBN)978-9-1470-4856-4 (ISBN)12249 (Archive number)12249 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2013-11-27Bibliographically approved
Stenström, M., Olander, B., Söderberg, J., Sandborg, M. & Alm Carlsson, G. (2001). Absorbed dose aspects on in vivo microtomography on small experimental animals. Journal of Bone and Mineral Research
Open this publication in new window or tab >>Absorbed dose aspects on in vivo microtomography on small experimental animals
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2001 (English)In: Journal of Bone and Mineral Research, ISSN 0884-0431, E-ISSN 1523-4681Article in journal (Refereed) Submitted
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-13567 (URN)
Available from: 2001-02-20 Created: 2001-02-20 Last updated: 2017-12-13
Söderberg, J. (2001). Fast neutron dosimetry: a study of basic dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections. (Licentiate dissertation). Linköping: Linköpings universitet
Open this publication in new window or tab >>Fast neutron dosimetry: a study of basic dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections
2001 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Basic dosimetric properties of fast-neutron beams with energies ≤80 MeV were explored using Monte Carlo techniques. Elementary pencil-beam dose distributions taking into account transport of all relevant types of released charged particles (protons, deuterons, tritons, 3He and a particles) were calculated and used to derive several absorbed dose distributions. Broad-beam depth doses in phantoms of different materials were compared and scaling factors calculated to convert absorbed dose in one material to absorbed dose in another. The scaling factors were in good agreement with available published data and show that water is a good substitute for soft tissue even at neutron energies as high as 80 Me V. The inherent penumbra and fraction of absorbed dose due to photons were also studied, and found to be consistent with published values.

Treatment planning in fast-neutron therapy is commonly performed using dose calculation algorithms designed for photon beam therapy. These algorithms have limitations in the physical models when applied to neutron beams. Monte Carlo derived neutron pencil-beam kernels were parameterized and implemented into the photon dose calculation algorithms of the TMS (MDS Nordion) treatment planning system. It was shown that these algorithms yield good results in homogeneous water media. However, the heterogeneity correction method of the photon dose calculation algorithm failed to calculate correct results in heterogeneous media for neutron beams.

Fundamental cross-section data are needed when calculating absorbed doses. To achieve results with adequate accuracy, neutron cross-sections are still not sufficiently well known. At the The Svedberg Laboratory in Uppsala, Sweden, an experimental facility has been designed to measure neutron-induced charged-particle production cross-sections for (n,xp), (n,xd), (n,xt), (n,x3He) and (n,xα) reactions at neutron energies up to 100 MeV. In order to derive the energy distributions of charged particles generated inside the production target, the measured data have to be corrected for the energy lost by the particles in the target. In this work a code (CRAWL) was developed for the reconstruction of the true spectrum. It uses a stripping method. With the limitation of reduced energy resolution, results using CRAWL compare well with those of other methods.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2001. p. 44
Series
Linköping Studies in Health Sciences. Thesis, ISSN 1100-6013 ; 48
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27572 (URN)12235 (Local ID)91-7219-975-X (ISBN)12235 (Archive number)12235 (OAI)
Presentation
2013-06-05, Ögonklinikens föreläsningssal, Universitetssjukhuset, Linköping, 09:15 (Swedish)
Opponent
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2013-07-10
Somsak, D., Atac, A., Bergenwall, B., Blomgren, J., Elmgren, K., Johansson, C., . . . Söderberg, J. (2000). Facility for measurements of nuclear cross sections for fast neutron cancer therapy. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 452(3), 484-504
Open this publication in new window or tab >>Facility for measurements of nuclear cross sections for fast neutron cancer therapy
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2000 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 452, no 3, p. 484-504Article in journal (Refereed) Published
Abstract [en]

A facility for measurements of neutron-induced double-differential light-ion production cross-sections, for application within, e.g., fast neutron cancer therapy, is described. The central detection elements are three-detector telescopes consisting of two silicon detectors and a CsI crystal. Use of ?E-?E-E techniques allows good particle identification for p, d, t, 3He and alpha particles over an energy range from a few MeV up to 100 MeV. Active plastic scintillator collimators are used to define the telescope solid angle. Measurements can be performed using up to eight telescopes at 20░ intervals simultaneously, thus covering a wide angular range. The performance of the equipment is illustrated using experimental data taken with a carbon target at En = 95 MeV. Distortions of the measured charged-particle spectra due to energy and particle losses in the target are corrected using a newly developed computer code. Results from such correction calculations are presented.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-26762 (URN)10.1016/S0168-9002(00)00455-1 (DOI)11362 (Local ID)11362 (Archive number)11362 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13
Söderberg, J. & Alm Carlsson, G. (2000). Fast neutron absorbed dose distributions in the energy range 0.5-80 MeV: a Monte Carlo study. Physics in Medicine and Biology, 45(10), 2987-3007
Open this publication in new window or tab >>Fast neutron absorbed dose distributions in the energy range 0.5-80 MeV: a Monte Carlo study
2000 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 45, no 10, p. 2987-3007Article in journal (Refereed) Published
Abstract [en]

Neutron pencil-beam absorbed dose distributions in phantoms of bone, ICRU soft tissue, muscle, adipose and the tissue substitutes water, A-150 (plastic) and PMMA (acrylic) have been calculated using the Monte Carlo code FLUKA in the energy range 0.5 to 80 MeV. For neutrons of energies ≤20 MeV, the results were compared to those obtained using the Monte Carlo code MCNP4B. Broad-beam depth doses and lateral dose distributions were derived. Broad-beam dose distributions in various materials were compared using two kinds of scaling factor: a depth-scaling factor and a dose-scaling factor. Build-up factors due to scattered neutrons and photons were derived and the appropriate choice of phantom material for determining dose distributions in soft tissue examined. Water was found to be a good substitute for soft tissue even at neutron energies as high as 80 MeV. The relative absorbed doses due to photons ranged from 2% to 15% for neutron energies 10-80 MeV depending on phantom material and depth. For neutron energies below 10 MeV the depth dose distributions derived with MCNP4B and FLUKA differed significantly, the difference being probably due to the use of multigroup transport of low energy (<19.6 MeV) neutrons in FLUKA. Agreement improved with increasing neutron energies up to 20 MeV. At energies >20 MeV, MCNP4B fails to describe dose build-up at the phantom interface and penumbra at the edge of the beam because it does not transport secondary charged particles. The penumbra width, defined as the distance between the 80% and 20% iso-dose levels at 5 cm depth and for a 10×10 cm2 field, was between 0.9 mm and 7.2 mm for neutron energies 10-80 MeV.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14360 (URN)10.1088/0031-9155/45/10/317 (DOI)000089865300017 ()
Available from: 2007-03-22 Created: 2007-03-22 Last updated: 2017-12-13
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