Which radioisotope is commonly used for permanent interstitial implants in the prostate gland?

Gold-198 is commonly used for permanent interstitial implants in the prostate gland because it has favorable physical and biological properties for this specific application. As a radioisotope, Gold-198 emits beta particles and has a half-life that allows it to deliver a therapeutic dose of radiation effectively while minimizing damage to surrounding healthy tissues.

The nature of interstitial brachytherapy involves placing the radioactive source directly into or near the tumor, which Gold-198 is well-suited for due to its ability to provide a localized radiation dose. This minimally invasive technique has shown to be effective in treating prostate cancer, and the use of Gold-198 allows for a controlled and sustained release of radiation over time.

Other radioisotopes, while beneficial for different types of treatments, do not offer the same combination of characteristics necessary for effective permanent prostate implants as Gold-198 does. For example, Cesium-137 and Cobalt-60 are more commonly associated with external beam radiation therapy rather than brachytherapy. Iodine-131 is primarily used for treating thyroid conditions and is not typically utilized in prostate cancer treatment. Thus, Gold-198 is the preferred choice for permanent interstitial implants in prostate cancer therapy.