Merge 1 Flashcards
Concerned with providing occupational
radiation protection
Minimizing radiation dose to the public
HEALTH PHYSICS
first radiation fatality
CLARENCE Dally 1904
benefits over the risk (cxr)
JUSTIFICATION
time/distance/shielding
LIMITATION
EQUATION:exposure
exposure rate*exposure
time
Sequencing on-off rather than continuous on
during examination (repeated UP and DOWN
motion- high quality examination and reduce
patient exposure)
FLUOROSCOPIC FOOT SWITCH:
- Is the relationship b/n the X-RAY INTENSITY
AND THE SID (distance between the source of
radiation and the Image receptor) - When the distance from the source is doubled, the intensity of radiation is reduced by one-fourth
- (doubling the distance)- from the source,
decreases dose by a factor of four - (tripling the distance)- decreases dose by nine-fold
- When the distance is halved, the intensity is
increased by a factor of four
INVERSE SQUARE LAW
formula for inverse square law
Intensity1/Intensity2=Distance2^2/Distance1^2
lines that represent positions of equal radiation
exposure in the fluoroscopy room (mR/hr)
milliRoentgen
ISOEXPOSURE LINES
1 TVL =
3.3 HVL
used to estimate the amount
that a protective barrier reduces radiation
intensity
TVL and HVL
Is the thickness of absorbing material necessary
to reduce the radiation intensity to half of its
original value
HALF VALUE LAYER-(filtration)
thickness of material
that will reduce the radiation intensity to
one-tenth of its original value
TENTH-VALUE LAYER
SHIELDING- PROTECTIVE APRON
0.5mmPb
is the maximum dose of radiation that in light of
present knowledge, produce no significant
radiation effects
MAXIMUM PERMISSIBLE DOSE (MPD)
