What is the difference between radiation therapy and nuclear medicine?

Treatment v. diagnos: Radiation therapy is the use of radiation or particle energy directed at a part of the body to shrink tumors in that location. It is treatment. Nuclear medicine is the use of radioactive isotopes in the proper form to localize pathology in the body. It is a form of diagnosis and not treatment although it might guide treatment by other means.

Energy levels: Generally (there are exceptions), nuclear medicine deals with radioisotopes of lower energy. The radioactive energy sources are generally joined to other chemicals or drugs that are administered to patients and detected by scans. Radiation therapy uses radioactive sources to form a beam of energy that is directed towards a particular tumor or part of the body with the intent of killing cancer.

Nuc Med injects dyes: In nuclear medicine, we inject radioactive "dyes" to image or treat patients. In radiation oncology, x-rays are generated outside the patient and irradiate tumors (usually) that are in the body. They treat different diseases.

I do not use: Unsealed sources (131 iodine) to treat thyroid cancer, (samarium 153) to treat bone pain, yttrium in zevlin or Bexxar (tositumomab) to treat lymphoma, and these are done along with diagnostic in nuc med. Radiotherapy depts use photons/ xrays, ?Protons and neutrons as beam therapy and sealed sources i-125 ir -192 for brachytherapy, low and high dose rates. Hope this helps!

Delivery: Radiation therapy usually refers to delivery of radiation via an external beam, whereas nuclear medicine therapies typically deliver the radiation to the target organ by injecting the tracer into the bloodstream.

Some differences: Nuclear medicine uses isotopes mainly for functional diagnoses of disorders of gall bladder, heart, brain, lungs, thyroid,bones, kidneys and bladder.Nuclear medicine has a few therapeutic uses including thyroid ablation and therapy for prostate bone metastases.Radiotherapy can involve radiation therapy with xray and proton beams, not usually considered part of nuclear medicine, but rad. oncology