Which term refers to the broad category that includes intraoperative radiation therapy, stereotactic radiosurgery, and stereotactic body radiation therapy?

• A. External Beam
• B. Types of External Beam Radiation
• C. Brachytherapy
• D. Cobalt-60 Unit (Gamma Knife)

Answer: (B)

The key idea is how radiation therapy is grouped by how the radiation is delivered. The techniques listed—intraoperative radiation therapy, stereotactic radiosurgery, and stereotactic body radiation therapy—are all delivered from outside the body with precise targeting, rather than from sources placed inside the body. That places them under the umbrella of external beam approaches, and they represent different forms or methods within that delivery type. So the broad category that includes these modalities is “types of external beam radiation,” which is why that option is the best fit.

External beam alone is close, but it’s just the mode of delivery, while the phrase “types of external beam radiation” explicitly categorizes the specific modalities that fall under that delivery method. Brachytherapy is internal radiation, so it doesn’t fit here. Gamma Knife is a specific device used to deliver stereotactic radiosurgery, which is indeed an external beam technique, but the question asks for the broad category, not a specific example or device.