exposure without screens over exposure with screens

amount of light emitted by screen for given amount of exposure

2 Types of Screen Speed

should be used to reduce patient exposure

- can increase beam penetration when high, - affects exposure to IR, - can cause larger potential difference when increased

needed to achieve a desired exposure to the IR

2 principal factors that affect amount of scattered radiation KI

scattering of incident photons onto an outer shell electron of atom

energy of incident photon is totally absorbed by inner shell electron which is ejected (Photoelectron) with kinetic energy

photon energy is converted to positron and electron

transfers negligible energy to atom

related to contributions of scattered photons at calibration

ratio of true dose rate to instrument’s response rate

- technical challenge for radiographers because of small size, require lower kVp & mAs - requires technologist to choose fast exposure

eliminate possibility of using automatic exposure control (AEC)

higher risk for children than adults

Exposure factors for adult skulls can be used for pedia patients _ years older

decrease kVp by 15% to compensate

2 FACTORS THAT CAN CAUSE MAGNIFICATION DP

Steel balls ___mm, difference in size between center less than ___mm

can be produced with materials that attenuate x-rays

made of fiberglass or plaster

MATERIALS THAT REQUIRE NO INCREASE IN EXPOSURE FA

MATERIALS THAT REQUIRE AN INCREASE IN EXPOSURE WASP