W07_08 Principles of radiation oncology

Question 1

what’s the difference between charged and uncharged particles in radiotherapy?

Answer 1

charged particles stop quickly and uncharged particles take longer to stop

Question 2

what’s the difference between direct and indirect damage to DNA when delivering radiotherapy?

Answer 2

direct: photon-DNA interaction;
indirect: photon-water interaction, oxygen radical/DNA interaction.

Question 3

out of the following types of DNA damage, which is the worst? base damage, sugar damage, protein cross-link, DNA cross-link, single-strand break, double-strand break

Answer 3

double stranded break

Question 4

linac, gamma knife, cyberknife, tomotherapy are examples of which kind of radiotherapy?

Answer 4

external beam

Question 5

radioactive seeds for therapy (e.g. prostate) is called what?

Answer 5

brachytherapy

Question 6

what are the three factors to consider for radiotherapy? (stressed many times in the lectures)

Answer 6

patient factors;
tumour factors;
normal tissue factors

Question 7

how much radiation is typically given? (in Gy)

Answer 7

20 Gy in 5 fractions, daily

Question 8

what’s the one generalizable side effect of radiation therapy?

Answer 8

fatigue

Question 9

note: radiation in the same site as a previous treatment is not a good thing

Answer 9

“the body does not forget radiation”

Question 10

what are side effects of whole brain radiation?

Answer 10

fatigue;
hair loss/scalp irritation;
headache;
nausea;
seizures;
focal neurological symptoms;
ear problems