RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

1. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology RADIATION PROTECTION INDIAGNOSTIC ANDINTERVENTIONAL RADIOLOGY Part 19.08: Optimization of protection in Mammography Practical exercise

2. Overview • To be able to apply quality control protocols to mammography equipment • To carry out film sensitometry-densitometry • Interpretation of results 19.08 : Optimization of protection in Mammography

3. IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology Part 19.08: Optimization of protection in Mammography Processor evaluation

4. Sensitometry (1) • Use a sensitometer to expose a film to light and insert the exposed side into the processor first • Measure the optical densities of the step-wedge with a densitometer 19.08 : Optimization of protection in Mammography

5. Sensitometry (2) • The values of interest are the base-plus-fog level of the film, the mid-density, and density difference 19.08 : Optimization of protection in Mammography

6. Densitometer 19.08 : Optimization of protection in Mammography

7. 11 12 13 16 17 18 20 21 10 14 15 19 1 2 3 4 5 6 7 8 9 Sensitometric strip A method of exposing film by means of a sensitometer and assessing the response of film to exposure and development 19.08 : Optimization of protection in Mammography

8. Film sensitometry parameters • Base + fog: The optical density of a film due to its base density plus any action of the developer on the unexposed emulsion, or possibly darkroom fog • Mid-Density: Measured on a step of the wedge with an optical density close to, but not less than 1.20. The mid-density is related to the speed of the film. • Density Difference: The difference between two steps on the wedge closest to 0.45 and 2.20. • Note: The steps producing these densities are chosen with fresh chemistry and film. These same steps are then used for all future quality control measurements. 19.08 : Optimization of protection in Mammography

9. Control film One, or more, box(es) of film selected and used only for quality control purposes. When changing from one control emulsion to another a cross-over procedure must be carried out (see ACR QC Manual). The control film must be the same emulsion type as is usually processed in the processor. If more than one type of film is processed, e.g., mammography and general radiography films, both types of film must be used for quality control purposes. 19.08 : Optimization of protection in Mammography

10. Processor QC Essentials • A photographic step wedge should be exposed daily and processed before any clinical films are processed. • Densities should be plotted on a control chart (see Chapters 2 and 5, Gray, et al. for details on control charts, and ACR Mammography QC Manual) 19.08 : Optimization of protection in Mammography

11. Control limits for mammography films 19.08 : Optimization of protection in Mammography

12. Key to processor QC • The key to processor is consistency in all aspects— • Using the same sensitometer and densitometer • Using the same control emulsion (or carrying out a crossover procedure when going to a new emulsion batch) • Immediately plotting the data on a control chart and analyzing the chart to determine if correction action is needed • Recording the correction action for future reference 19.8 : Optimization of protection in Mammography

13. Where to Get More Information European protocol for the quality control of the physical and technical aspects of mammography screening. http://euref.org/index.php?option=com_phocadownload&view=category&id=1&Itemid=8 American College of Radiology Mammography Quality Control Manual, Reston VA, 1999. Quality Control in Diagnostic Imaging, Gray JE, Winkler NT, Stears J, Frank ED. Available at no cost. http://www.diquad.com/QC%20Book.html 19.08 : Optimization of protection in Mammography