In Vivo Dosimetry for Brachytherapy Study

This study is testing a real-time radiation dose measurement technique (called in vivo dosimetry) during brachytherapy — a form of internal radiation treatment — to improve accuracy and safety for patients treated for prostate or gynecological cancers. **You may be eligible if...** - You are 18 or older - You are receiving high-dose-rate (HDR) brachytherapy using an iridium-192 source, either alone or combined with external radiation, for: - Prostate cancer (primary or recurrent) - Gynecological cancers including cervical, vulval, vaginal, or endometrial cancer at various stages **You may NOT be eligible if...** - You are not receiving HDR brachytherapy with iridium-192 - You have a cancer type not included in the study Talk to your doctor to see if this trial is right for you.