module 11 chapter 12-- occupational radiation protection

occupational workers are allowed a ___ annual dose than the general public

higher

The smaller group (workforce vs general public) can receive a higher EfD without ____ the genetically significant dose of the population as a whole

altering

what are high dose areas?

any area that involves fluoroscopy or mobiles

what are examples of high dose areas?

surgery, interventional, fluoroscopy, cardiac cath

what are low dose areas?

any areas that have permanent shielding or low beam energy

what are examples of low dose areas?

mammo, CT, DEXA

what are examples of no dose areas?

sonography and MRI

protecting the patient helps protect you, which means you should:

avoid repeats, collimate, control scatter, beam filtration, exposure factors

on mobiles, how should you position yourself to protect yourself from radiation?

position yourself 90 degrees to the x-ray beam scattering object (patient) or the x-ray source

the intensity of scatter radiation 1 meter from the patient is approximately ___ of the useful beam intensity

0.1 % (1/1000)

95% of exposure comes from:

fluoro and portables

additional ways to protect yourself in fluoroscopy:

collimation, filtration, shielding (protective curtain, bucky slot cover), exposure factors, SSD, cumulative timer, tube housing.

when is a dosimeter required?

when there is the possibility of receiving more than 1/10 of the DL

when a radiation worker declares pregnancy, what occurs?

RSO provides counseling, a separate dosimeter is issued, and you must wear a maternity protective apron

where is the baby dosimeter worn?

at waist level under the shield

what is the monthly EqD to fetus and the cumulative pregnancy fetal dose?

0.5 mSv ; 5.0 mSV

what is the maternity protective apron requirements?

0.5 mm lead equivalent over width and length, extra 1 mm lead equivalent panel that runs transversely across the width of the apron

what is the primary protective barrier?

any wall/floor to which the primary beam may be directed

what is the purpose of a primary protective barrier?

prevents direct or unscattered radiation from reaching radiation worker

where is the primary protective barrier generally located?

perpendicular to the primary x-ray beam

what are the lead requirements for the primary protective barrier?

0.16 cm of lead and must extend 2.1 m up from the floor of a wall

what is the secondary protective barrier?

any wall or barrier that is never struck by primary beam radiation

what are examples of where you might find secondary protective barriers?

control panel (from scatter radiation and leakage radiation)

what are the lead requirements of a secondary protective barrier?

0.08 cm of lead

when we say distance when talking about barrier thickness, what are we referring to?

between the source and barrier

what is occupancy?

time use of the area being proctored; occupancy factor (T)

what is the occupancy factor of full occupancy? (work areas)

T = 1

what is the occupancy factor of frequent occupancy? (corridors, restrooms)

T = 1/4

what is the occupancy factor of occasional occupancy? (waiting rooms, stairways, janitor closet)

T = 1/8, T = 1/16

what is the occupancy factor for patient exam and treatment rooms?

1/2

what is the occupancy factor for corridors, patient rooms, employee lounges, staff restrooms?

1/5

what is the occupancy factor for corridor doors?

1/8

what is the occupancy factor for public restrooms, vending areas, storage areas, outdoor areas with seating, unattended waiting rooms, patient holding?

1/20

what is the occupancy factor for outdoors, unattended parking lots, attics, stairways, uattended elevators, janitor’s closets?

1/40

controlled area is occupied primarily by:

radiation personnel and patients under RSO supervision

uncontrolled area can be occupied by:

anyone

controlled area- reduce exposure to less than:

1 mSv/week

uncontrolled area- reduce exposure to less than:

20 μSv/ week or 1 mSv/yr

workload is the level of ___ in the room in units of ___

radiation activity; units of (mA)(min)/week

what is considered a busy workload?

500 mAmin/week

what is the workload in a private office?

100 mAmin/week

what is use factor?

percentage of time that x-ray beam is on

what is the use factor for primary barriers (floor and wall exposed to primary beam)

1

what is the use factor for secondary wall barriers:

1 (will always be struck by scatter or leakage radiation)

what is the use factor for doors and walls of radiation rooms?

1/4

what is the use factor for a chest unit?

one wall with use factor of 1, other walls use factor =0

for protective barrier calculations, kVP is used as the measure for penetrability; assumption of constant operation at __ kVp for diagnostic and __ kVp for mammo; likely that barrier will be too thick rather than too thin

100 kVp; 30 kVp

fluoro only units require less shielding because all radiation is:

secondary

what is the use factor for partial vs occasional use?

partial = U = ¼ ; occasional use= U = 1/16

what are the management principles for occupational dose reduction?

new employee training, in-service training