If the DNA in the cell nucleus is damaged by ionizing radiation, the

If the DNA in the cell Inside the body, alpha
Outside the body,
nucleus is damaged by radiation causes most alpha radiation causes
ionizing radiation, the
damage as it is
least damage because
cell may grow without strongly absorbed by
it cannot penetrate
control and form a
cells and causes the
the skin.
tumour. This is how
most damage.
radiation can cause
Inside the body
Outside the body,
gamma radiation
gamma radiation can
causes least damage penetrate the body to
as it is most likely to reach cells and organs
pass through the body
and cause damage.
without being
absorbed by the cells.
A very short half life
would be best for the
tracer because there
is less risk to the
patient from
A very long half-life
would be best for a
tracer because it
would give plenty of
time to inject the
sample into the
patient and use the
Geiger counter.
Small doses of the
Iodine-131 has a half
radioactive isotope
life of 8 days which
are injected to
means that it would
minimise the radiation be suitable to use as a
tracer in the human