Hello, my name's Peter O'Sullivan.
I'm a medical physicist here at the Royal Berkshire Hospital,
and I'm going to show you the radioactive iodine room.
The patient comes into the room,
and is administered with the radioactive iodine,
and for that reason they have to stay here between two and four days.
Because of that, they have their own facilities,
such as a bathroom and shower,
and also they have their own entertainment,
such as a television, DVD, phone and patient line system.
Now I'm gonna show you how the patient is sealed in the room.
The protective door outside closes.
When administering iodine 131 therapy,
we require that the patient has to be locked away
in a special room for several days.
This is because they are highly radioactive,
and this would be hazardous to the people around them.
The treatment is used for two separate conditions -
carcinoma of the thyroid and thyrotoxicosis.
For thyrotoxicosis, the patient is administered a much lower dose,
and while they still have restrictions regarding close contact with people,
they're not required to remain in hospital.
For carcinoma of the thyroid,
the patient is given a very large dose,
either three or 5.5 gigabecquerels at this hospital,
and for that reason they must remain within the room.
You're gonna swallow the capsule, which has radioactive iodine in,
and over the course of the next few hours,
that will become absorbed into your thyroid.
The aim of that is to ablate or completely remove
any of the residual thyroid tissue you have there.
How much of that is actually gonna go to my thyroid?
Only a very small percentage will be absorbed into your thyroid,
the rest of it will be excreted from your body in the urine.
If you could drink extra fluids, that would encourage that process.
Iodine 131 has two types of radiation, beta and gamma.
The beta radiation destroys the cells in the thyroid,
and the gamma radiation is used for imaging at the end of the treatment.
I'm now going to give you the radioactive capsule.
Because it's radioactive, it's in a lead pot here,
but it also has to be clean,
so what we do is we have a clean applicator here,
which I'm gonna screw in the top,
and if you could take the top off and lift this up
and put this to your lips,
If you just have a sip of water now.
OK.
Do you think you've swallowed that OK?
Yeah, definitely, yeah.
The protection of staff administering the treatment
is based both on the time of the treatment, which is minimised,
and also the distance from the patient, which is maximised.
In order to monitor our doses we use TLDs,
both on our person and also extremity monitors,
which we wear on our fingers.
The doses on the TLDs are checked twice monthly
and the reports are given to us.
How long you'll remain radioactive will depend on both the physical
and the biological half-life of iodine 131.
The physical half-life is eight days,
but your biological half-life will be variable,
depending on how much of the iodine your thyroid will absorb.
The dose readings are taken using a dose rate meter,
which is a Geiger Muller tube.
We take readings close to the neck of the patient,
and also a distance reading across the room.
The two readings are used for different purposes.
The close reading gives us an indication
of the maximum dose rate coming out from the patient,
whereas the distant reading gives us an integrated dose reading
emanating from the patient.
When the patient leaves hospital, we take a final dose reading.
We use this to determine
how long they need to restrict their close contact
with members of their family and friends.
This is to ensure they don't receive hazardous levels of radiation.