Transcript IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology RADIATION PROTECTION IN DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY Part 19.09: Optimization of protection in Mammography Practical.

IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
RADIATION PROTECTION IN
DIAGNOSTIC AND
INTERVENTIONAL RADIOLOGY
Part 19.09: Optimization of protection in
Mammography
Practical exercise
IAEA
International Atomic Energy Agency
Overview
• To be able to apply quality control protocol
to screen-film mammography equipment
• To assess darkroom fog from light leaks and
safelights
• Interpretation of results
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19.09 : Optimization of protection in Mammography
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IAEA Training Material on Radiation Protection in Diagnostic and Interventional Radiology
Part 19.09: Optimization of protection in
Mammography
Dark room fog evaluation
IAEA
International Atomic Energy Agency
Darkroom fog
• Remain in the darkroom for a minimum of
five minutes with all the lights, including the
safelights, turned off
• Ensure that adjacent rooms are fully
illuminated
• Inspect all those areas likely to be a source
of light leakage, e.g., around processor and
doors. Also, check for indicator lights on the
processor or other electronics in the room
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Darkroom fog
• Correct all light leaks which are visible before
continuing with this test.
• Visually inspect safelights for light leaks, cracks in
the filters or faded areas, and replace as needed.
• Check the wattage of the safelight bulb, the
distance from the safelight to the film handling
surface, and the type of safelight filter. Be sure
these meet the film manufacturer’s requirements.
• Turn on all safelights for the next part of the test
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Darkroom fog
• To measure the fog, uniformly expose a film
to an optical density between 1.20 and 2.00
• Place the exposed sheet of film on the
counter with the emulsion side up.
• Cover half of the film with an opaque sheet,
e.g., cardboard, and expose the film to the
darkroom environment for 2 minutes
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Darkroom fog
• Process the film
• Measure the optical density using a
densitometer on either side of the edge
formed by the fog light (under the cardboard
and area not covered by the cardboard).
• The difference of the two densities is the fog
level of the film, i.e., the amount of fog
contributed by light sources in the darkroom
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Darkroom fog
Limiting value :Fog < 0.05
Frequency :
Initially, every six months
or when light leakage is
suspected
Equipment :
Cardboard to cover film,
densitometer
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Darkroom fog
• If the fog is greater than 0.05, corrective
action is required.
• There are three potential sources of fog–
light from adjacent areas, safelights, and
indicator lights. Determine the source of fog
and take appropriate corrective action.
• Note: It may be necessary to cover indicator
lights with dark tape to reduce the amount of
light in the darkroom.
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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
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