nuclear radiation

medical tracers

a tracer is a radioactive isotope that can be used to track the movement of substances around the body

why are gamma emitters usually used for medical tracers

-are highly penetrating and so will be able to pass through the body and be detected outside the body

-are less ionising than some other forms of radiation, the harm caused to the patient is also minimised.

what to consider when using radioactive tracer

1. tracer must emit radiation that can pass out of the body and be detected

2. tracer just not be strongly ionising to minimise damage to body tissues

3. the tracer must not decay into another radioactive isotope

4. must have a short half-life so it is not present in the body for a long time

why is alpha radiation not used in radioactive tracers

can pass out body and highly ionising

radiotherapy

using ionising radiation to destroy certain cancers-gamma rays pass into body and destroy tumour

issue with radiotherapy

healthy tissues may also be damaged as the radiation passes through the body

what happens in external radiotherapy

• During external radiotherapy, beams of gamma rays are directed at the cancerous tumour

  • The machine rotates to target the tumour from different angles

  • This minimises the exposure of healthy tissue to the gamma rays and minimises damage to healthy cells

internal radiotherapy

• During internal radiotherapy, small pellets of radioactive materials can also be inserted into a tumour exposing it directly to radiation

advantage of internal radiotherapy

radiation is targeted precisely to the tumour. There is less damage to healthy tissue