shielding guideline for diagnostic x-ray installation Flashcards
what is the role of the RSO/RPO in design or renovation of x-ray facilities
act as an advisor on all radiation protection aspects
ensure installation complies with all regulations
what type of barrier protects from primary radiation?
primary barrier
what type of barrier protects from scatter radiation?
secondary barrier
what type of barrier protects from leakage radiation?
secondary barrier
the radiation levels in controlled areas that are occupied routinely by
radiation workers must be such that no radiation worker is occupationally
exposed to more than ___ mSv per year
20
the radiation levels in uncontrolled areas must be such that no person
receives more than __mSv per year
1
what makes a primary barrier
barrier will be required to attenuate the direct X-ray beam
what makes a secondary barrier
stray/ scatter radiation only
what are 3 common barrier materials
lead, concrete, gypsum wallboard
what is the primary barrier equation
K = Pd^2 / WUT
in the primary barrier equation, what is P
max permissible weekly exposure
in R/week
in the primary barrier equation, what is d
distance in METRES from target to primary area
in the primary barrier equation, what is W
workload in mA-min/week
in the primary barrier equation, what is U
use factor
in the primary barrier equation, what is T
occupancy factor
in the primary barrier equation, what is K
exposure per unit workload, at unit distance
in R/mA at 1 metre
does the shielding calculation take into account any (pt, object, etc) that attenuates?
no!
what are the 6 steps of the workload calculation
- avg exams/week
- weight abg of exposure per exam
- avg mAs per exposure
- avg exposures / week
- average mAs / week
- ma minutes / week
workload is measured in what
mA minutes per week
what are the 6 occupancy factors?
T=1, T=1/5, T=1/5, T=1/8, T=1/20, T=1/40
what areas are T=1
fully occupied by an individual
office/reception areas, labs, pharmacies, adjacent x-ray rooms, living quarters, control rooms
what areas are T=1/2
rooms used for pt exams and treatments
what areas are T=1/5
corridors and halls, pt rooms, staff lounges and rest rooms
what areas are T=1/8
corridor and hallway doors
what areas are T=1/20
public toilets, unattended vending areas, storage, outdoor seating, patient holding areas
what areas are 1/40
outdoor areas with only trash=nsient/vehicular traffic, unattended parking lots, drop-off areas stairways, elevators, janitor’s closets
what are the 3 use factors for primary barrier
U=1, U=1/4, U=1/16
what is primary U=1
floors of rad rooms, walls with IR, other walls, doors or ceiling exposed to beam regularly
what is primary U=1/4
doors and wall areas not regularly exposed to beam
what is primary U=1/16
ceiling areas not routinely exposed
what is the use factor for secondary barriers?
always assumed to be 1
