Rad Bio Equations

Question 1

What is the primary barrier equation

Answer 1

K=Pd^2/WUT

Question 2

What does P stand for in the PBE

Answer 2

P=Max permissible weekly exposure (need to know if area is primary or secondary) (.002-Controlled or .04-Uncontrolled)

Question 3

What does D stand for in the pBE

Answer 3

d=Distance from target to primary area

Question 4

What does W stand for in the PBE

Answer 4

W=Measure of operational time/amount of use (mA-min/week) of equipment

Question 5

What does U stand for in the PBE

Answer 5

U=Use factor (fraction of time the beam pointed at the barrier in question)

Question 6

What does T stand for in the PBE

Answer 6

T=Occupancy factor (fraction of time that area is occupied by an individual while x-ray is operating)

Question 7

How do you calculate workload?

Answer 7

Workload=(Avg exams per week x number of exposures x Avg mAs/60)

Question 8

How do you calculate ESE

Answer 8

ESE (entrance skin exposure)=mR x (SCD/SOD)^2

Question 9

How do you calculate SOD

Answer 9

SOD=(SID-OID-Thickness of tissue)

Question 10

How do ou calculate RBE?

Answer 10

RBE=Dose in 250 REV mGy or standard dose to produce effect/dose in test radiation to produce same effect

Question 11

How do you calculate DAP?

Answer 11

DAP=Air kerma x SA

Question 12

How do you calculate Efd?

Answer 12

EfD=D x Wr x Wt

Question 13

How do you calculate EQd?

Answer 13

EqD=D x WR

Question 14

What is WT?

Answer 14

The carcinogenic effect of each organ (radiosensittivity)

Question 15

What is WR?

Answer 15

The biological imact amoungst various types of radiation