title: Radio-iodine-labelled 5-iodo-2-thiouracil: a potential radiopharmaceutical for establishing the viability of ocular melanoma after radiation therapy.
abstract: Radio-iodine-labelled thiouracil has been evaluated as a radiopharmaceutical for establishing the viability of ocular melanoma after radiation treatment. The uptake of 125I-5-iodo-2-thiouracil (125I-ITU) was studied in X-ray irradiated and non-irradiated melanotic melanomas implanted in Syrian golden hamsters. Uptake of 125I-ITU in melanomas 4 days after irradiation with 40 Gy X-ray was 25% of the value found in non-irradiated controls, 12 days after such treatment it was 10% of that value. Twenty-one days after radiation treatment the melanomas showed regrowth and uptake of 125I-ITU was about equal to that in non-treated controls. Uptake of 125I-ITU in melanomas after 10 Gy X-ray irradiation was higher and uptake in tumours after 20 Gy was only slightly lower than the uptake by non-irradiated melanomas. The results indicate that the iodine labelled-thiouracil uptake test may be useful as an additional diagnostic issue for assessing the viability of ocular melanoma after radiation therapy.
mesh_terms: D000818:Animals; D002830:Choroid Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D006224:Cricetinae; D007457:Iodine Radioisotopes / Q000378:metabolism; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D008647:Mesocricetus; D011877:Radionuclide Imaging; D013889:Thiouracil / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D013889:Thiouracil; C036667:iodothiouracil