Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of cerebral metastases meeting the following criteria:

- One to three presumed brain metastases

- Metastases must be from a histologically confirmed extracerebral site (e.g.,
lung, breast, prostate)

- Histologic confirmation may have been from the primary tumor site, from
another metastatic site (e.g., osseous metastasis, adrenal metastasis), or
from the metastatic brain lesion(s)

- Each lesion must measure less than 3.0 cm by contrast MRI of the brain performed
within the past 21 days

- Lesions must not be within 5 mm of the optic chiasm or within the brainstem

- Eligibility for treatment with gamma knife or linear accelerator-based radiosurgery
confirmed by a radiation oncologist

- No primary germ cell tumor, small cell carcinoma, or lymphoma

- No leptomeningeal metastases

- Hormone receptor status not specified

PATIENT CHARACTERISTICS:

- Male or female

- Menopausal status not specified

- ECOG performance status 0-2

- Not pregnant

- Negative pregnancy test

- Fertile patients must use effective contraception

- Male patients must continue to use contraception for 3 months after the
completion of radiotherapy

- No pacemaker or other MRI-incompatible metal in the body

- No known allergy to gadolinium

PRIOR CONCURRENT THERAPY:

- More than 7 days since prior and no concurrent chemotherapy

- No prior cranial radiotherapy

- No prior resection of cerebral metastases

- Concurrent hormonal agents, steroids, and/or anticonvulsants allowed