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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 16.4: Optimization of protection in fluoroscopy Practical exercise. Overview / Contents.

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RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

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  1. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology RADIATION PROTECTION INDIAGNOSTIC ANDINTERVENTIONAL RADIOLOGY Part 16.4: Optimization of protection in fluoroscopy Practical exercise

  2. Overview / Contents • To become familiar with quality control tests in fluoroscopy • To measure the low contrast resolution and noise according to the suggested procedures • Interpretation of results 16.4: Optimization of protection in fluoroscopy

  3. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Part 16.4: Optimization of protection in fluoroscopy Low contrast resolution and noise

  4. Low contrast resolution and noise Purpose : • to measure the low contrast resolution and the influence of noise on low contrast detectability Equipment : • image quality phantom (Leeds phantom) • 2 mm Cu filter 16.4: Optimization of protection in fluoroscopy

  5. Low contrast resolution • The low contrast resolution determines the size of detail that can be visibly reproduced when there is only a small difference in density relative to the surrounding area • Low contrast resolution is considerably limited by noise. • The perception threshold in relation to contrast and detail size can be determined, for example, by means of a contrast-detail curve. 16.4: Optimization of protection in fluoroscopy

  6. Leeds Fluoroscopy PhantomNoise and contrast loss • Incorporates: • 19 discs, each 11 mm diameter, of different x-ray contrasts. 16.4: Optimization of protection in fluoroscopy

  7. Leeds Fluoroscopy Phantom Noise and contrast loss • Typical fluoroscopic image of the test object. View the small circles at center and • count the number of visible circles Images from: http://www.leedstestobjects.com/modules/products/product_setup/file_library/SFS%20SET%20product%20specifications.pdf 16.4: Optimization of protection in fluoroscopy

  8. Leeds Fluoroscopy Phantom Noise and contrast loss 16.4: Optimization of protection in fluoroscopy

  9. Noise and contrast loss Interpretation of results The threshold contrast is determined by the detail which can only just be detected. The threshold contrast of a modern system in average adjustment should not be greater than the following values: 16.4: Optimization of protection in fluoroscopy

  10. Leeds Fluoroscopy Phantoms Overall Imaging Performance • Incorporates: • 108 discs in 12 groups of different diameters; in each group there are 9 discs of different X-Ray contrasts. • Is used to assess the threshold-contrast detail-detectability. 16.4: Optimization of protection in fluoroscopy

  11. Leeds Fluoroscopy Phantoms Overall Imaging Performance Typical fluoroscopic image of the test object. 16.4: Optimization of protection in fluoroscopy

  12. Leeds Fluoroscopy Phantoms Overall Imaging Performance Interpretation of results Data are plotted as a function of detail diameter. Threshold detection index is defined as H (A) = [C(A) A]-1 16.4: Optimization of protection in fluoroscopy

  13. 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

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