Radiotherapy

Question 1

What are the different types of radiotherapy techniques?

Answer 1

1. photons
2. electrons
3. superficial x-rays
4. brachytherapy
5. radioactive treatments
6. protons

Question 2

What is brachytherapy? What types of cancer is it used for?

Answer 2

A form of radiotherapy where a sealed radiation source is placed inside or next to the area requiring treatment. Effective treatment for:
- cervical
- prostate
- breast
- oesophageal
- skin cancer
can also be used to treat tumours in many other body sites.

Question 3

What is a photon?

Answer 3

(not accurate definition in physics sense)
wave-like packets of energy
deposit energy when they meet matter

Question 4

How do gamma rays arise?

Answer 4

emitted from radioactive decay of atomic nuclei

high frequency therefore high energy

Question 5

How are x-rays formed?

Answer 5

By the interaction of electrons with a nucleus

High energy and very short wavelengths (but still longer than gamma rays)

Question 6

What is meant by ‘1 Gray’?

Answer 6

1 Gray = deposition of one joule of (radiation) energy in 1 kg of matter or tissue

Gray = the unit of an absorbed dose

Question 7

What occurs in cells exposed to radiation?

Answer 7

> 1000 damaged DNA bases
~1000 single stranded DNA breaks
~40 double stranded DNA breaks