physics : applied radiation therapy

Question 1

3 things. involved in applied radiation therapy

Answer 1

shielding
time
distance

Question 2

what 2 things are involved in attenuation

Answer 2

scatter

absorption

Question 3

formula for attenuation

Answer 3

I= Io x e^ µx

Question 4

what is intensity

Answer 4

the no. of xray photons

Question 5

the energy of the beam depends

Answer 5

on energy of photons

Question 6

what is the formula for energy in this situation

Answer 6

E=hf

h= planks constant
f=frequency

Question 7

what does u stand for

Answer 7

linear attenuation co efficent ….

this is the am of attenuation per metre of material

Question 8

what does x stand for

Answer 8

thickness. of material

Question 9

if intensity is half than its original

Answer 9

x= ln2/u

Question 10

how to reduce exposure to patients

Answer 10

preplanning treatment therefore reducing time spent exposed to radiation

Question 11

if you double distance

Answer 11

you quarter the dose

Question 12

dose distance formula

Answer 12

D1d1= D2d2
D= dose
d or R = distance

Question 13

3 axis of rotation

Answer 13

gantry - horizontal axis
couch - vertical axis
collimator- beam axis … rotates in gantry while gantry rotates

Question 14

the axii

Answer 14

interact in the mechanical isocentre

Question 15

what is isocentre

Answer 15

point around linac rotates

should be tumour