RADIATION SAFETY HIGH YIELD Flashcards
things that affect scatter?
body part thickness body part and tube orientation field size kVp using grids
how can we minimize scatter?
benefits?
collimation
maximize distance from source, 6 ft
faster exposure
grids-block forward scatter and improve image
affect of collimation?
lowers patient dose
restricts volume of irradiated tissues
improves image contrast and decreases scatter
how is beam restricted to allow for further distance?
aperture diaphragm
cones
cylinders
how are the grids used? kVp or body parts?
kVp>70
body parts<12cm
what are the layers for structural shielding?
tenth value layers
half value layers
barriers
primary barrier is how thick?
secondary?
- 6 mm
0. 8 mm
what are the two types of areas?
controlled and uncontrolled
how can we protect the patient?
note on filtration, like affect of kVp on mmAL for following kVps:
<50 kVp
50-70 kVp
>70 kVp
minimize movement
shorten exposure
use lead aprons
*maximize kVp and minimize mAs
- 5 mmAl
- 5 mmAl
- 5 mmAl
how do we estimate patient dose?
skin dose
gonadal dose
bone marrow dose
how do we ensure occupational safety?
film badges thermoluminescent dosimeters don't stand in the primary beam maximum permissible dose lead garments lead goggles
apron thickness for primary beam? secondary?
lead gloves?
- 5 mm
- 25 mm
0.25 mm
what is the consideration of wrap around apron for the pregnant worker
0.5 mm lead in front and 0.25 mm in back w/ 1.0mm patch on pelvis
where should we stand as the operator?
intensifier side
what is considered for fluoroscopy safety?
scatter to unshielded personnel 1 ft from patient is 1/100
* 1/1000 at 1 meter
use freeze frames
pulse fluoroscopy
move intensifier closer to patient, one step back decreases 4x exposure
shielding
