what can stop the different types of radiation from being harmful?
alpha = can be stopped by paper and only has a range of a few cm in air
beta = can be stopped by a thin sheet of metal (aluminium) and has a range of 1m in air
gamma = can be stopped by thick lead and has an unlimited range in air
how us nuclear radiation used in medicine?
radioactive tracers = patient drinks water containing a tiny bit of radioactive iodine, if kidney is blocked substance goes up into kidney but does not go out again and can be seen on detector. iodine is used as it has a half-life of 8 days so it is long enough to be used for the test, but also is able to have decayed within a few weeks, its emit gamma radiation so can be detected outside the body and it decays stably.
how are gamma cameras used?
patient is infected with gamma emitting radioactive isotope solution, it is absorbed by organ and a gamma camera detects the radiation emitted by the solution. gamma rays pass through holes in the thick lead grid infant of the detector but only detects rays from nuclei directly infront of it. detector signals build up an image of where the radioactive isotope is located in the organ.
how can radiation treat cancer?
radioactive implants are used to destroy cancerous tumours, it is emitted from an isotope of cobalt which has a half-life of five years. gamma radiation used for better penetration.
risks of radiation
it can ionise atoms and molecules within living cells - leading to tissue damage
lower doses of radiation tend to cause minor damage without killing cells - creates mutated cells that divide rapidly (cancer)
higher doses kill cells completely - radiation sickness, loss of hair, tiredness
