Mark's uncle is about to have a procedure to treat his prostate cancer. The treatment involves placement of small pellets close to the tumor to deliver a localized dose of radiation. What type of nuclear therapy is this?

Brachytherapy places radioactive sources, such as small pellets or seeds, inside or very close to a tumor. This delivers radiation locally, as in the prostate cancer treatment described. External beam radiation comes from a machine outside the body, while radiopharmaceuticals are radioactive substances administered to travel through the body.

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