17th September

Question 1

alpha emission gives off what

Answer 1

2 protons and 2 neutrons

Question 2

Anger gamma camera was developed by who

Answer 2

Hal Anger

Question 3

Unit of radioactivity

Answer 3

Bq or MBq

Question 4

how is a gamma camera designed?

Answer 4

first the gamma hits cllimator, then scintillation crystail, then photomultiplier tubes then the energy circuitary

Question 5

technetium-99m half life

Answer 5

6 hours

Question 6

Iodium 111 half life

Answer 6

67.9 h

Question 7

Gallium 67 half life

Answer 7

78.3

Question 8

what are collimators in gamma camera?

Answer 8

The photons are high energy - too high to be focused with a lens.

gamma rays need to be directed towards the patient

Question 9

most common collimator for gamma ray

Answer 9

parallel holes - stops angulated gamma

Question 10

parallel hole collimator distinct properties

Answer 10

1:1 relationship between object and projection ??

Question 11

parallel hole collimator distinct properties

Answer 11

1:1 relationship between object and projection .

high atomic number

Question 12

issue with parallel collimator?

Answer 12

get a much sharper immage from the centre of the point source as laterally more gamma rays are absorbed

Question 13

full width half maximum

Answer 13

to make sure the spread of the gamma rays remains relatively even from the point source

Question 14

collimator resolution

Answer 14

Rc = S (L + Z ) / L

Question 15

why can you only optimise spatial resolution or sensitivity

Answer 15

the collums can be narrow so are accurate but not much detail or wide causing lots of detail from lots of gamma but also lots of pollution

Question 16

sensitivity inverse square rule

Answer 16

higher snesitivity needs higher count rate

Question 17

gamma ray - effect of crustal thickness on sensitivity

Answer 17

draw graph. at higher energy gamma ray need a higher thickness for the same sensitivity