4.4.3.3 Uses of nuclear radiation

explore internal organs

use a radoactive tracer

* A **tracer** is a radioactive isotope that can be used to track the movement of substances, like blood, around the body
* Gamma emitters are usually used for this purpose
* Gamma rays are highly penetrating and so will be able to pass through the body and be detected **outside** the body

\
* This allows an internal image of the body to be created


* Since gamma rays are less ionising than some other forms of radiation, the harm caused to the patient is also minimised \n

issues when using radioactive tracer

the tracer must emit radiation that can pass out of the body and be detected (gamma or beta radiation)

\
the tracer must not be strongly ionising to minimise damage to body tissue

\
the tracer must not decay into another radioactive isotope

\
the tracer must have a short life so it is not present in the body for a long period of time

why is nuclear radiation dangerous

Nuclear radiation is dangerous due to ionisation (knocking electrons out of atoms, making them charged).

Why is ionisation dangerous to living cells?

When atoms in living cells become ionized one of three things usually happen – the cell dies, the cell repairs itself, or the cell mutates incorrectly and can become cancerous.

why do you not want a tracer with a long half life

they will continue to decay in the body for a long time and cause significant damage to body tissue

radiotherapy

controlling or destroying unwanted tissue

gamma rays pass into the body and destroy the tumour

Gamma emitters are used to emit gamma rays, which are directed onto certain areas of the body with cancerous cells, which absorb the energy and die, controlling the disease o It is used to control any other unwanted tissue too

issues with radiotherapy

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

o However, as it is hard to direct accurately, surrounding healthy cells may also be irradiated, and their destruction causes unhealthy side effects

internal radiotherapy

small pellets of radioactive materials can also be inserted into a tumour exposing it directly to radiation

targets area

less damage to healthy tissue

external radiotherapy,

beams of gamma rays are **directed** at the cancerous tumour

* Surrounding healthy tissue tends to be shielded to avoid causing any damage

what are radioactive isotopes used for in medicine

medical imaging, treatment of cancer, and as tracers to monitor organs

•How useful a radioactive isotope is depends on:

–its half-life

–the type of radiation it gives out.