treatment

Question 1

name things that x-rays and gamma rays have in common?

Answer 1

similar wavelengths
ionising radiation
very penetrating and can pass into the body to treat internal organs
used in diagnosis and therapy

Question 2

what must the radioisotopes used in medicine need to have as properties?

Answer 2

give out gamma or beta radiation because these can pass through skin
have a suitable half-life
not be toxic to humnas

Question 3

what are the different types of radiation that can be emitted from the nucleus of an unstable atom?

Answer 3

alpha, beta or gamma

Question 4

what is alpha absorbed by not paper?

Answer 4

absorbed by the skin so is of no use for diagnosis or therapy

Question 5

what does beta radiation pass through?

Answer 5

passes through skin, not bone. Its medical applications are limited but it is used for example to treat eyes

Question 6

what does gamma pass through in surgery?

Answer 6

it is very penetrating and is used in medicine. Cobalt 60 is a gamma emitting radioactive material that is used to treat cancers

Question 7

what does ionisation radiation do?

Answer 7

damages living cells, increasing the risk of cancer

Question 8

how can cancer cells be destroyed?

Answer 8

exposing the affected area to large amounts of radiation. This is called radiotherapy

Question 9

how can materials be made radioactive?

Answer 9

when there nuclei absorbs extra neutrons in a nuclear reactor

Question 10

what is the ionising power of alpha beta and gamma?`

Answer 10

alpha- very strong
beta-medium
gamma-weak

Question 11

what is the range in the air for alpha beta or gamma?

Answer 11

alpha about 5cm
beta about 1m
gamma large its intensity reduces with distance

Question 12

how are x-rays produced?

Answer 12

a hot cathode (negatively charged) emits electrons that are attracted by a highly posotive charge
when the fast moving electrons hit the target some of the kinetic energy is used to emit x-rays but most of its converted to heat

Question 13

name advantages of x-rays?

Answer 13

produced only when needed
an x-ray machine allows the rate of production of the x-rays to be controlled
some x-rays can have a much higher energy than some gamma rays

Question 14

what happens when the nucleus of an atom of an radioactive substance decays?

Answer 14

it emits an alpha or beta particle and loses any surplus energy by emitting gamma rays

Question 15

what is a radioactive tracer used for?

Answer 15

to investigate inside a persons body without surgery`

Question 16

what is the most commonly used tracer? and what does it emit?

Answer 16

technetium-99m-gamma radiation

Question 17

what is iodine-123 trace problems in?

Answer 17

the thyroid gland

Question 18

how is a tracer inserted into a person?

Answer 18

is mixed with food or drink or injected

Question 19

how is a tracers progress measured through the body?

Answer 19

using a detector such as a gamma camera connected to a computer

Question 20

what is a radioisotope used to destroy?

Answer 20

a tumour in the body

Question 21

how is the tumour destroyed?

Answer 21

three sources of radiation each providing one third of the required dose, are arranged around the patient with the tumour at the centre

Question 22

what limits damage to the brain when a tumour is being treated?

Answer 22

the healthy tissue only receives one third of the dose