Boron Neutron Capture Therapy Using Boronophenylalanine-Fructose Complex in Treating Patients With Metastatic Melanoma

DISEASE CHARACTERISTICS: * Histologically confirmed melanoma * Metastatic disease * Brain metastases, skin metastases, or soft tissue metastases of the head and neck or the extremities * Accessible lesion(s) for boron neutron capture therapy (BNCT) * No clear progression of disease at other sites than the ones intended for treatment with surgery and/or BNCT * Measurable disease by MRI within the past 4 weeks * Lesion(s) ≥ 10 mm in diameter * Indication for palliative radiotherapy that is intended to be delivered as BNCT PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Karnofsky 70-100% Life expectancy * Not specified Hematopoietic * Neutrophil count ≥ 2,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Hemoglobin ≥ 10 g/dL Hepatic * Bilirubin ≤ 2.5 times upper limit of normal (ULN)\* * Transaminases ≤ 2.5 times ULN\* * Alkaline phosphatase ≤ 2.5 times ULN\* NOTE: \*Unless due to reversible reaction to antiseizure medication Renal * Creatinine ≤ 2.5 times ULN * Blood urea nitrogen ≤ 2.5 times ULN Cardiovascular * No congestive heart failure * No newly diagnosed or unstable angina pectoris * No uncontrolled arrhythmias * No uncontrolled conduction defects * No recent coronary artery disease * No other severe heart disease Pulmonary * No severe pulmonary disease, including severe obstructive or restrictive lung disease Other * No history of phenylketonuria * No severe gastrointestinal disease * No active peptic ulcer disease * No uncontrolled endocrine disease * No pre-existing serious mental or organic brain disease (e.g., epilepsy) * No psychological, familial, sociological, or geographical condition that would preclude study compliance * Able to travel to the Netherlands via public transportation * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy * No concurrent immunologic or biologic therapy * No concurrent colony-stimulating factors (e.g., epoetin alfa or filgrastim \[G-CSF\]) Chemotherapy * No concurrent chemotherapy Endocrine therapy * No concurrent hormonal therapy Radiotherapy * No prior radiotherapy to site(s) proposed for study treatment * No other concurrent radiotherapy Surgery * See Disease Characteristics Other * Recovered from all prior anti-tumor therapy (excluding alopecia and sensitive peripheral neuropathy ≤ grade 2) * No other concurrent anticancer therapy * No other concurrent investigational drugs