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Nuclear Physics and Medicine
Transcript of Nuclear Physics and Medicine
What particles are in an atom?
X-rays pass through soft tissues in body without being stopped
Hard things like bone stop the x-ray and cast a white shadow on a detector
Fat and muscle appear grey because they stop some of the radiation
Barium meals involve taking a drink which contains barium
Barium shows up the outline of the gut on x-rays because x-rays don't pass through it
Radiation is dangerous because it can kill living cells
Radiation can also be used to kill cancer cells
What radiation is emitted from the nucleus of an atom?
This means that healthy tissues get a little bit of the radiation but the cancer cells receive the full dose
A concentrated beam of gamma rays is directed at the cancer from lots of different angles
Radiation is also used to sterilise medical instruments by killing germs
Uses of X-rays
Bones are very dense
They contain lots of calcium which
has a high atomic number
They absorb lots of the x-ray
so very little passes through
CT scans (Computed Tomography) also use x-rays.
The patient lies on a table and is moved through a doughnut shaped machine.
This creates images that are slices through the body.
CT scans are useful because they can give clear pictures of different parts of the body:
By adding together different slices we can create 3D pictures of the body
One problem with CT scans is high radiation.
What does the electromagnetic spectrum include?
Just one CT scan is the same as 100 chest x-rays or 4 years of normal background radiation.
Another use of x-rays is to look at blood vessels
X-rays can show blockages like clots, weaknesses in the walls and build up of fat in the arteries when a special dye is used
This technique is used to examine things like heart attacks and strokes and can also be used in treatment
Radiation can be useful
There are lots of ways doctors use radiation to investigate problems and treat patients
Lots and lots of ways: x-ray, CT, MRI, PET, radiotherapy, barium meal/swallow/enema, angiography ...
A newer use of CT scans is to inject patients with a sugar molecule linked to a fluorescent molecule to show up areas of the body using lots of energy, like cancers
Iodine and thyroid cancer
Iodine-131 picked up by damaged thyroid cells, which are then killed by the radioactive isotope
What properties would a radioactive source need for use in radiotherapy?