1 / 8

RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology. RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY. Part 15.2: Optimization of protection in radiography Practical exercise. Overview.

watson
Download Presentation

RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology RADIATION PROTECTION INDIAGNOSTIC ANDINTERVENTIONAL RADIOLOGY Part 15.2: Optimization of protection in radiography Practical exercise

  2. Overview • Subject matter : quality control of general radiography system • Step by step procedure to be followed to implement the considered QC test: • Radiation output linearity • kVp and mA “compensation” • Interpretation of results 15.2: Optimization of protection in radiography

  3. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Part 15.2: Optimization of protection in radiography The tube output measurement

  4. The tube output measurement Purpose : • To check that the radiation output [mGy/mAs] remains constant as the mA is varied Material: • An electronic device (multi-function meter) capable of measuring kV, time, and dose 15.2: Optimization of protection in radiography

  5. Radiation output linearity (I) Method : • Use an ion chamber or solid state detector at ~ 75 cm from the focal spot • Place some lead vinyl under the detector to standardize backscatter and protect the phototimer • Use manual mode, fixed 70 kVp and exposure time (~ 100 ms) • Measure dose at all mA settings used clinically (also useful to measure kVp) 15.2: Optimization of protection in radiography

  6. Radiation output linearity (II) Analysis : • For each exposure, calculate the mAs, then the radiation dose per mAs (this ideally should be constant) • Find the maximum and minimum values of dose/mAs • Calculate variation = (max - min)/(max + min) 15.2: Optimization of protection in radiography

  7. Radiation output linearity (III) • The variation Should be < 0.1 • If > 0.1, then check the kVp - high values of dose/mAs might be associated with high kVp • If the tube has large and small focus settings, measure linearity for each separately 15.2: Optimization of protection in radiography

  8. Where to Get More Information Quality Control in Diagnostic Imaging, Gray JE, Winkler NT, Stears J, Frank ED. Available at no cost. http://www.diquad.com/QC%20Book.html 15.3: Optimization of protection in radiography

More Related