Radiation

Question 1

True or False

Hypoxic environments makes tumour cells radiosensitive

Answer 1

False
Oxygen is needed to produce free radicals
Hypoxic tumour cells are radio-resistant

Question 2

What is meant by fractionation?

Answer 2

Time between radiotherapy treatment cycles to allow:

1. Time for normal cell to recover
2. Tumour cells in radio-resistant phase of the cell cycle to enter a more sensitive phase
3. Time for reoxygenation of hypoxic tumour cells

Question 3

What is meant by a Bacquerel?

Answer 3

SIU of radioactive decay activity

Question 4

What is meant by a Gray?

Answer 4

SIU of absorbed radiation

Question 5

What are the three particles released during radioactive decay?

Answer 5

Alpha particles - 2 neutrons and 2 protons
Beta particles - beta minus or beta plus
Gamma rays - high frequency electromagnetic waves

Question 6

What is meant by a Sievert?

Answer 6

SIU of the biological effect of radiation on human tissue

Question 7

What are the acute effects of radiotherapy?

Answer 7

Mucositis
Oedema and swelling
Infertility
Fatigue

Question 8

What are the medium to long-term effects of radiotherapy?

Answer 8

Fibrosis and scarring

Secondary malignancy

Question 9

What is the amount of radiation of a CT abdomen?

Answer 9

400 CXR equivalent

2.7 years of background radiation

Question 10

What is the amount of radiation of a chest x-ray?

Answer 10

2.4 days of background radiation

Question 11

What is the typical daily dose of radiotherapy?

Answer 11

2.0 Gray