Stereotaxic intracavitary irradiation for cystic craniopharyngiomas.

Stereotaxic intracavitary irradiation with instillation of phosphorus-32 (32P) colloidal chromic phosphate was performed in nine patients with cystic craniopharyngiomas. Serial neurological, ophthalmological, neuroendocrinological, and radiological examinations were performed before and after treatment. Dosimetry was determined based on a computerized tomography (CT) estimation of tumor volume, and was calculated to provide a tumoricidal dose (200 to 300 Gy) to the cyst wall.

Comparison of computerized tomographic and radionuclide methods in determining intracranial cystic tumor volumes.

The dosimetry of radioactive phosphorus (32P) for intracavitary treatment of cystic brain tumors is dependent upon accurate determination of the cyst volume. The authors have used both high-resolution computerized tomography (CT) scanning and an isotope dilution technique with technetium-99m (99mTc) sulfur colloid to determine cyst volumes in an experimental model and in six patients with intracerebral cystic tumors. In six separate comparisons using an experimental phantom "cyst," no significant differences between CT and 99mTc values were detected.

Stereotactic intracavitary irradiation of cystic neoplasms of the brain.

Ten patients with intracranial cystic tumors underwent stereotactic intracavitary irradiation using 32P colloidal chromic phosphate. Accurate dosimetry (25,000-30,000 rad to the cast wall) was achieved by volume estimation using computed tomography. Between 1 and 15 months after surgery both craniopharyngioma and astrocytoma cysts regressed.