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)
Where the highest occupational exposure of
diagnostic x-ray personnel occur: together w/
mobile radiography
FLUOROSCOPY
no somatic or
genetic responses should occur
RADIATION DOSE below MPD
risk is small, but not
zero
DOSES at level of MPD
