Whole brain radiation is typically used for which scenario?

• A. Metastatic tumors with multiple sites
• B. A single small tumor only
• C. Non-cancerous brain lesions
• D. Brain infections

Answer: (A)

Whole brain radiotherapy is used when cancer has spread to many parts of the brain. Metastatic disease often involves multiple sites, and some lesions may be too small to see on imaging or are scattered beyond single-target areas. Treating the entire brain provides regional control of both visible tumors and potential microscopic disease, helping relieve symptoms and slow progression when multiple sites are involved.

When there is a single small tumor, a focused approach—such as stereotactic radiosurgery or surgical removal—is usually preferred to limit exposure of healthy brain tissue and reduce side effects. Non-cancerous brain lesions are not treated with whole brain radiation as a routine approach, and brain infections are managed with antimicrobial therapies rather than radiation. The key idea is that whole brain radiation offers broad coverage suitable for widespread intracranial disease rather than a single localized lesion.