title: In vivo comparison of 16 alpha[77Br]bromoestradiol-17 beta and 16 alpha-[125I]iodoestradiol-17 beta.
abstract: An in vivo comparison of two estrogen-receptor-binding radiopharmaceuticals of high specific activity, 16 alpha-[77Br]bromoestradiol-17 beta and 16 alpha-[125I]iodoestradiol-17 beta, has been carried out in immature female rats. The iodoestradiol has slightly higher uterine uptake at 1 hr after injection, whereas the brominated analog has significantly enhanced uptake at later times. The similar behavior of the two compounds in vivo suggests that estradiol labeled with I-123, Br-77, or Br-75 could be used interchangeably for the imaging of breast tumors containing estrogen receptors. In addition, coinjection of 16 alpha-[125I]iodoestradiol as an internal standard has been shown to be useful for comparison of different radiohalogenated estrogens.
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging; D001966:Bromine; D004958:Estradiol / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism; D013997:Time Factors; D014599:Uterus / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D011960:Receptors, Estrogen; D004958:Estradiol; C034554:16 alpha-bromo-17 beta-estradiol; C024871:16 alpha-iodoestradiol; D001966:Bromine