P4 - Treatment

Question 1

What are the properties needed for radioisotopes to be used in medicine?

Answer 1

• give out gamma or beta radiation as they pass through skin
• have a suitable half life
• not be toxic

Question 2

What is the difference between diagnosis and therapy?

Answer 2

Diagnosis: finding out what is wrong
Therapy: treatment

Question 3

What is radiotherapy?

Answer 3

Radiotherapy is destroying cancer cells by exposing the affected area of the body to large amounts of radiation.

Question 4

How do X rays produce an image?

Answer 4

When X rays pass through the body the tissues absorb some of the radiation. The amount absorbed depends on the thickness and the density of the absorbing material.

Question 5

Alpha radiation is of no use in medicine. Why?

Answer 5

It cannot get through skin.

Question 6

How are x rays produced?

Answer 6

A hot cathode emits elections that are attracted by a positive tungsten target. When the electrons hit the target some of their kinetic energy is used to emit x rays.

Question 7

What are the advantages of x rays?

Answer 7

• produced only when needed
• rate of production can be controlled
• the energy of x rays can be changed
• x rays have higher energy than gamma

Question 8

How do radiographers protect themselves from exposure to radiation?

Answer 8

They leave the room while the radiation source is switched on.

Question 9

What techniques are used to prevent gamma radiation from destroying healthy cells?

Answer 9

• a radiation source is slowly rotated around the patient to spend out the damage
• three sources of radiation are arranged around the patients head