What is the difference between radiation therapy and nuclear medicine?

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.
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.
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.
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.
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.
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!

Related Questions

What are the differences between radiography, radiation therapy, and nuclear medicine?

Diagnosis vs therapy. Radiation therapy uses high-energy xrays to kill cancer cells or other types of growths in the body, for therapeutic purposes. Radiology uses lower-energy xrays to view the inside of the body, for diagnostic purposes. Nuclear medicine uses the injection of radioactive material into the body either to view "active" areas within the body (diagnostic) or to kill malignant cells (therapuetic). Thanks. Read more...
Different radiation. Radiography or x-ray involves low dose ionizing radiation with images of chest , skeleton, skull etc. Radiation therapy uses high dose ionizing to treat tumors with external or internal irradiation. Nuclear medicine involves low dose ionizing radiation in form of isotopes that are internally injected intravenously. Inhaled, injected subcutaneously, or ingested orally. Read more...

How do diagnostic radiography, radiation therapy and nuclear medicine differ?

Different radiation. Radiography or x-ray involves low dose ionizing radiation with images of chest , skeleton, skull etc. Radiation therapy uses high dose ionizing to treat tumors with external or internal irradiation. Nuclear medicine involves low dose ionizing radiation in form of isotopes that are internally injected intravenously. Inhaled, injected subcutaneously, or ingested orally. Read more...

Is nuclear medicine considered internal radiation therapy? For some reason, it seems like all the definitions of internal radi don't include nuclear.

Yes. Nuclear Medicine includes tests such as PET and other scans that can assess tumors & evaluate the function of various organs. It also includes giving radioisotopes by mouth or vein for the treatment of certain cancers (most commonly thyroid, lymphoma and bone mets) and hyperthyroidism. This is different than brachytherapy done by Radiation Oncologists in which radioactive seeds are put in a tumor. Read more...
Physiologic study. Nuclear medicine involves using internal radiation in order to define function of heart, lungs, bones, liver/spleen, stomach, thyroid gland, lymph system, kidneys, bladder, brain, parathyroid gland and gall bladder. Some isotopes are injected iv, inhaled, and some ingested. Isotopes of higher doses are used to treat thyroid diseases.Amount of irradiation controlled for each ndividual. Read more...