RATIONALE: Radiation therapy uses high-energy x-rays and other sources to damage tumor cells. Giving radiation therapy in different ways may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of indium In 111 pentetreotide in treating patients who have refractory cancer.

OBJECTIVES: I. Determine the maximum tolerated dose (MTD), toxic effects, and the preliminary antitumor activity of indium In 111 pentetreotide.

OUTLINE: This is a dose escalation study. Patients receive indium In III pentetreotide (OctreoScan) IV on day 1. Imaging is conducted on days 3 and 6. Treatment continues weekly for a total of 4 courses in the absence of disease progression or unacceptable toxicity. Cohorts of at least 3 patients receive escalating doses of OctreoScan until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 patients experience dose limiting toxicities. Patients are followed every 3 months for the first year, then every 6 months thereafter.

PROJECTED ACCRUAL: Up to 35 patients will be accrued for this study.

• Brain and Central Nervous System Tumors
• Childhood Langerhans Cell Histiocytosis
• Gastrointestinal Carcinoid Tumor
• Head and Neck Cancer
• Intraocular Melanoma
• Islet Cell Tumor
• Kidney Cancer
• Lung Cancer
• Melanoma (Skin)
• Neoplastic Syndrome
• Neuroendocrine Carcinoma of the Skin
• Pheochromocytoma

DISEASE CHARACTERISTICS: Histologically proven malignancy with no alternate treatments available Measurable or evaluable progressive disease Somatostatin receptors present on tumor and uptake demonstrated on diagnostic scan with OctreoScan

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 3 months Hematopoietic: Platelet count at least 100,000/mm3 Absolute neutrophil count at least 1,500/mm3 Hepatic: Total bilirubin no greater than 2.0 mg/dL Renal: Creatinine clearance at least 40 mL/min Other: No active infections Not HIV positive No coexisting medical condition Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since prior wide field radiation therapy Surgery: Recovery from prior surgery