We histologically studied uveal melanomas treated with surgery only (enucleation or ciliochoroidectomy), low-dose (20 Gy) preenucleation radiation followed by enucleation, or enucleated melanomas after high-dose (50 to 80 Gy) charged-particle beam therapy. There was significantly less bromodeoxyuridine uptake in irradiated vs nonradiated melanomas (P less than .0001). Similarly, tissue culture growth of irradiated tumors was significantly less (P less than .007). These data demonstrate destruction of reproductive integrity of helium ion-irradiated melanomas. The incorporation of bromodeoxyuridine and fine needle aspiration biopsy techniques may be useful in the delineation of successfully irradiated tumors from tumors with apparent growth secondary to radiation vasculopathy.