What term describes placing radioactive materials inside the body to treat cancer?

• A. External beam radiation therapy
• B. Brachytherapy
• C. Chemotherapy
• D. Immunotherapy

Answer: (B)

Placing radioactive material inside the body to treat cancer is brachytherapy. In this approach, sealed radioactive sources are placed directly into or near the tumor, delivering a high radiation dose from within the body and sparing surrounding healthy tissue. This internal placement is what sets brachytherapy apart from external beam radiation therapy, where radiation originates outside the body and passes through healthy tissue to reach the tumor. Chemotherapy uses systemic drugs that circulate throughout the body, not implanted radioactive sources. Immunotherapy relies on modulating the immune system to attack cancer, without internal radioactive materials. Brachytherapy is used for various cancers and can involve temporary or permanent implants, with different dose rates depending on the clinical situation.