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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
tracer must emit radiation that can pass out of the body and be detected
tracer just not be strongly ionising to minimise damage to body tissues
the tracer must not decay into another radioactive isotope
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
