conclusion:

I HAVE LEARNT:

what a gamma ray can do to DNA.
that cancer can be treated with radiotherapy not just chemotherapy.
the difference between an X-ray and nuclear radiation, and that radiation doesn't have to be nuclear - it can be to do with electrons.
A half-life is the amount of time it takes for half the original quantity of a radioisotope to become stable, not half of the total radiation that will be emitted.
That different radioisotopes have different half-lives. Hospitals will keep most substances on site for 10 half-lives, and then they will be treated and taken to landfill.
Scintillation crystals can turn gamma ray readings into 3D images.
Radiation can diagnose diseases.
Too high a dose of radiation can lead to acute radiation sickness and cell death and mutilation.
Humans can only survive certain doses of radiation.

Nuclear medicine is a very complicated field, with questions of ethics and safety applicable to it. Whilst it can diagnose, fight, and possibly cure diseases like cancer, it can also cause acute radiation syndrome. If you think about it, it's almost like snake bites - the venom is also the cure, exposure to radioactivity causes cancer but it also fights it.The disposal methods for radioactive waste created in hospitals are not strict, and hospitals grade their waste as low-level, meaning they can treat it and leave it in radioactive landfill after 10 half lives. Sometimes outside services will treat it for them, and there is always a possibility of sabotage. Even once radioactive waste is disposed of, a risk is posed by natural disasters, which could contaminate the environment surrounding the "disposal" site. Radioisotopes used in hospitals usually have half-lives under 90 days, which can aid this problem, however brachytherapy tablets (used to treat cancer), which use isotopes such as caesium-137, can have half-lives of 30 years. It's very dangerous for these radioisotopes to be on Earth, as they could cause calamity. Nuclear medicine is also not completely sustainable - once the world runs out of the radioisotopes required in nuclear medicine - that's it. However, in the United States alone, over 20 million lives are benefited each year by nuclear medicine. Many people can thank these procedures for their lives, and their quality of life. This form of medicine can accomplish feats no drug can, and is a very important development in medicine. I think that to stop using it because of the negatives associated with it is the wrong decision. It saves lives, and although it can be dangerous, most things can. Medicine has side effects, diseases are becoming immune to antibiotics, a surgeon's knife could slip - yet we still use all of these methods and they can save lives. Nuclear medicine has downsides that shouldn't be overlooked, and we should be trying to figure out ways to solve these problems. However, nuclear medicine is too valuable to discard in the meantime, because it would cost countless lives.