liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Radiation dose and image quality in diagnostic radiology: optimization of the dose - image quality relationship with clinical experience from scoliosis radiography, coronary intervention and a flat-panel digital detector
Linköping University, Department of Medicine and Care, Radiology. Linköping University, Faculty of Health Sciences.
2001 (English)Doctoral thesis, comprehensive summary (Other academic)Alternative title
Stråldos och bildkvalitet i diagnostisk radiologi (Swedish)
Abstract [sv]

Det är känt att röntgenstrålning kan orsaka cancersjukdomar, hudskador och andra sidoeffekter. Därför är det viktigt och även föreskrivet i lag att strålexpaneringen inom diagnostisk radiologi skall sänkas så långt som möjligt. Detta kallas på engelska ALARA-principen (As Low As Reasonably Achievable). stråldosen är kopplad till bildkvalitet och denna får inte sänkas så långt att det diagnostiska värdet av en undersökning äventyras. Processen att nå en sådan balans mellan dos och bildkvalitet kallas optimering. Syftet med denna avhandling är att fmna och utvärdera metoder för att optimera förhållandet mellan stråldos och bildkvalitet inom diagnostisk radiologi med fokus på klinisk användbarhet. Arbetet utfördes i tre huvuddelar.

Optimering av skoliosröntgen: I första delen utvärderades två nyligen utvecklade metoder får digital skoliosröntgen (digital exponering och pulsad genomlysning). De järnfårdes även med film-skärmsystem som var den tidigare standardmetoden. Stråldosen mättes som Kerma area-produkt (KAP), ytdos (Entrance surface dose, ESD) och effektiv dos; bildkvaliteten värderades med ett kontrast-detaljfantom och genom visuell analys på kliniska bilder. Noggrannheten i vinkelmätningar värderades också. stråldosen för digital exponering var nästan dubbelt så hög som för film med jämförbar bildkvalitet medan pulsad genomlysning hade en mycket låg dos men betydligt sämre bildkvalitet. Variabiliteten i vinkelmätningar var tillräckligt låg i alla metoder. Därefter optimerades inställningarna för digital exponering till en betydligt lägre stråldos med viss sänkning av bildkvaliteten jämfört med utgångsläget.

Direktdigital detektor: I den andra delstudien utvärderades en direktdigital detektor med ett kontrast-detaljfantom där stråldosen mättes som ingångsdos i fantomet. Den direktdigitala detektorn gav bättre bildkvalitet vid lägre dos jämfört med både bildplattor och film. Jämförbar bildkvalitet med bildplattor nåddes vid ungefär en tredjedel av dosen.

Optimering av perkutan koranar intervention (PCI): I tredje delstudien undersöktes påverkan på stråldos och bildkvalitet av olika inställningar vid kranskärlsröntgen och PCI. Utifrån dessa fynd sänktes dosraten för genomlysning till en tredjedel. Dossänkningen utvärderades i en serie bestående av 154 PCI-procedurer före och 138 efter optimeringen. Genom denna optimering sänktes det totala KAP-värdet signifikant till två tredjedelar av ursprungsvärdet.

Sammanfattningsvis påvisar denna avhandling möjligheterna till dossänkning i diagnostisk radiologi genom optimering av den radiografiska processen.

Abstract [en]

X-rays are known to cause malignancies, skin damage and other side effects and they are thus potentially dangerous. Therefore, it is essential and in fact mandatory to reduce the radiation dose in diagnostic radiology as far as possible. This is also known as the ALARA (As Low As Reasonably Achievable) principle. However, the dose is linked to image quality and the image quality may not be lowered so far that it jeopardizes the diagnostic outcome of a radiographic procedure. The process of reaching this balance between dose and image quality is called optimization. The aim of this thesis is to propose and evaluate methods for optimizing the radiation dose - image quality relationship in diagnostic radiography with a focus on clinical usefulness. The work was performed in three main parts.

Optimization of scoliosis radiography: In the first part, two recently developed methods for digital scoliosis radiography (digital exposure and pulsed fluoroscopy) were evaluated and compared to the standard screen-film method. Radiation dose was measured as Kerma area-product (KAP), Entrance surface dose (ESD) and effective dose; image quality was assessed with a contrastdetail phantom and through Visual grading analysis. Accuracy in angle measurements was also evaluated. The radiation dose for digital exposure was nearly twice as high as the screen-film method at a comparable image quality while the dose for pulsed fluoroscopy was very low but with a considerably lower image quality. The variability in angle measurements was sufficiently low for all methods. Then, the digital exposure protocol was optimized to a considerably lower dose with a slightly lower image quality compared to the baseline.

Flat-panel detector: In the second part, an amorphous-silicon direct digital flat-panel detector was evaluated using a contrast-detail phantom, measuring dose as entrance dose. The flat-panel detector yielded a superior image quality at a lower dose than both storage phosphor plates and screen-film. Equivalent image quality compared to storage phosphor plates was reached at about one third of the dose.

Optimization of percutaneous coronary intervention (PCI): In the third part, influence of various settings on radiation dose and image quality in coronary catheterisation and PCI was investigated. Based on these findings, the dose rate for fluoroscopy was reduced to one-third. The dose reduction was evaluated in a clinical series of 154 PCI procedures before and 138 after the optimization. Through this optimization, the total KAP was significantly reduced to two-thirds of the original value.

In summary, this thesis indicates the possibility of dose reduction in diagnostic radiology through optimization of the radiographic process.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet , 2001. , 75 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 706
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-27483Local ID: 12137ISBN: 91-7373-143-9 (print)OAI: oai:DiVA.org:liu-27483DiVA: diva2:248035
Public defence
2001-12-07, B-husets aula, Universitetssjukhuset, Örebro, 13:00 (Swedish)
Opponent
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-10-24Bibliographically approved
List of papers
1. Digital Radiography of Scoliosis with a Scanning Method: Initial Evaluation
Open this publication in new window or tab >>Digital Radiography of Scoliosis with a Scanning Method: Initial Evaluation
Show others...
2001 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 218, 402-410 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To evaluate the radiation dose, image quality, and Cobb angle measurements obtained with a digital scanning method of scoliosis radiography.

MATERIALS AND METHODS: Multiple images were reconstructed into one image at a workstation. A low-dose alternative was to use digital pulsed fluoroscopy. Dose measurements were performed with thermoluminescent dosimeters in an Alderson phantom. At the same time, kerma area-product values were recorded. A Monte Carlo dose calculation also was performed. Image quality was evaluated with a contrast-detail phantom and visual grading system. Angle measurements were evaluated with an angle phantom and measurements obtained on patient images.

RESULTS: The effective radiation dose was 0.087 mSv for screen-film imaging, 0.16 mSv for digital exposure imaging, and 0.017 mSv for digital fluoroscopy; the corresponding kerma area-product values were 0.43, 0.87, and 0.097 Gy · cm2, respectively. The image quality of the digital exposure and screen-film images was about equal at visual grading, whereas fluoroscopy had lower image quality. The angle phantom had lower angle values with digital fluoroscopy, although the difference in measured angles was less than 0.5°. The patient images showed no difference in angles.

CONCLUSION: The described digital scanning method has acceptable image quality and adequate accuracy in angle measurements. The radiation dose required for digital exposure imaging is higher than that required for screen-film imaging, but that required for digital fluoroscopy is much lower.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27101 (URN)11748 (Local ID)11748 (Archive number)11748 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
2. Digital Radiography of Scoliosis with a Scanning Method: Radiation Dose Optimization
Open this publication in new window or tab >>Digital Radiography of Scoliosis with a Scanning Method: Radiation Dose Optimization
Show others...
2003 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 13, no 3, 543-551 p.Article in journal (Refereed) Published
Abstract [en]

The aim of this study was optimization of the radiation dose–image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm2 and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-26783 (URN)10.1007/s00330-002-1476-1 (DOI)11388 (Local ID)11388 (Archive number)11388 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
3. Image quality vs radiation dose for a flat-panel amorphous silicon detector: a phantom study
Open this publication in new window or tab >>Image quality vs radiation dose for a flat-panel amorphous silicon detector: a phantom study
2001 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 11, no 9, 1704-1709 p.Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to investigate the image quality for a flat-panel amorphous silicon detector at various radiation dose settings and to compare the results with storage phosphor plates and a screen-film system. A CDRAD 2.0 contrast-detail phantom was imaged with a flat-panel detector (Philips Medical Systems, Eindhoven, The Netherlands) at three different dose levels with settings for intravenous urography. The same phantom was imaged with storage phosphor plates at a simulated system speed of 200 and a screen-film system with a system speed of 160. Entrance surface doses were recorded for all images. At each setting, three images were read by four independent observers. The flat-panel detector had equal image quality at less than half the radiation dose compared with storage phosphor plates. The difference was even larger when compared with film with the flat-panel detector having equal image quality at approximately one-fifth the dose. The flat-panel detector has a very favourable combination of image quality vs radiation dose compared with storage phosphor plates and screen film.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-26902 (URN)10.1007/s003300100851 (DOI)11526 (Local ID)11526 (Archive number)11526 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
4. Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): I. Experimental studies
Open this publication in new window or tab >>Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): I. Experimental studies
2002 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 12, no 10, 2571-2581 p.Article in journal (Refereed) Published
Abstract [en]

The objectives of this study were to evaluate the influence on image quality and dose to the patient and operator of various equipment settings for percutaneous coronary intervention (PCI), and to optimize the set-up. With an Alderson phantom, different settings, such as projection, protective screens, filtration, image intensifier size and collimation, were evaluated. Kerma-area product (KAP) was recorded as a measure of patient dose and scattered radiation was measured with an ionization chamber. Effective dose for a standardized PCI procedure was measured with thermoluminescent dosimeters inside the phantom. Image quality was evaluated with a contrast-detail phantom. Based on these findings, the equipment set-up was optimized to a low fluoroscopy dose rate with a sufficient image quality. Several operating parameters affected dose, particularly scattered radiation. The optimization reduced the fluoroscopy KAP rate from 44 to 16 mGy cm2/s using 15 cm of acrylic. The effective dose was reduced from 13 to 4.6 mSv for a standardized PCI procedure. Radiation dose to patient and operator in PCI is heavily dependent on both equipment set-up and operating parameters which can be influenced by the operator. With a careful optimization, a large reduction of radiation dose is possible.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-80126 (URN)10.1007/s00330-001-1237-6 (DOI)12271400 (PubMedID)
Available from: 2012-08-21 Created: 2012-08-21 Last updated: 2017-12-07Bibliographically approved
5. Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): II. Clinical evaluation
Open this publication in new window or tab >>Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): II. Clinical evaluation
2002 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 12, no 11, 2813-2819 p.Article in journal (Refereed) Published
Abstract [en]

In a previous part of this study, the fluoroscopy dose rate was reduced in a cardiac catheterization laboratory. The objectives of the present study were to evaluate the effects in a clinical population undergoing percutaneous coronary intervention (PCI) of the dose-reducing measures detailed previously. Kerma area-product (KAP) values were first recorded for 154 patients undergoing PCI. Then, the fluoroscopy KAP rate was reduced from 44 to 16 mGy cm2/s by increasing filtration and reducing the image intensifier dose request. After this optimization, KAP was recorded for another 138 PCI procedures. After adjustment for differing proportions of combined procedures (coronary angiography+PCI), the total KAP was reduced to 67% of the original value with a 95% confidence interval from 57 to 78%, statistically significant. The mean total KAP values were 93.6 Gy cm2 before and 69.1 Gy cm2 after optimization. The KAP for digital acquisition did not change significantly. It is possible to make a large dose reduction in PCI by reducing the fluoroscopy dose rate. This dose reduction is beneficial for both patients and staff.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-26776 (URN)10.1007/s00330-001-1238-5 (DOI)11381 (Local ID)11381 (Archive number)11381 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved

Open Access in DiVA

No full text

By organisation
RadiologyFaculty of Health Sciences
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 898 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf