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Digital Radiography of Scoliosis with a Scanning Method: Radiation Dose Optimization
Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
Philips Medical Systems, Best, The Netherlands.
Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
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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.

Place, publisher, year, edition, pages
2003. Vol. 13, no 3, 543-551 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-26783DOI: 10.1007/s00330-002-1476-1Local ID: 11388OAI: diva2:247333
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-08-21Bibliographically approved
In thesis
1. 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
Open this publication in new window or tab >>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
2001 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Stråldos och bildkvalitet i diagnostisk radiologi
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.
Linköping University Medical Dissertations, ISSN 0345-0082 ; 706
National Category
Medical and Health Sciences
urn:nbn:se:liu:diva-27483 (URN)12137 (Local ID)91-7373-143-9 (ISBN)12137 (Archive number)12137 (OAI)
Public defence
2001-12-07, B-husets aula, Universitetssjukhuset, Örebro, 13:00 (Swedish)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-10-24Bibliographically approved

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