title: A gamma camera re-evaluation of potassium iodide blocking efficiency in mice.
abstract: The protection of the thyroid against radioiodine uptake has been an important safety concern for decades. After several studies examined potassium iodide blockade efficacy in the 1960's and 1970's, a standard dosage was prescribed by both the World Health Organization and the U.S. Food and Drug Administration. In this paper, we tested the effectiveness of a scaled version of that standard dosage in comparison to higher doses in mice. A novel gamma camera was employed with a high spatial resolution for precisely quantifying activity within the thyroid and a field of view large enough to image the entire mouse body. Thyroid and whole-body 125I biodistribution was analyzed immediately after exposure and 1 and 7 days later. It was found that 1 h after exposure five times the scaled human dose blocked thyroid uptake about 40% more effectively than the 1X scaled dose. Even after 1 d and 7 d, five times the recommended scaled human dose blocked approximately 10% more effectively than the 1X dose. These data suggest the need for continued evaluation of the effectiveness of KI as a blocking agent and the application of novel, non-invasive technologies to this important human health issue.
authors.affiliation: Department of Physics, College of William and Mary, Williamsburg, VA 23185, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Hammond
authors.forename: Eric L
authors.initials: EL
authors.lastname: Bradley
authors.forename: Robert E
authors.initials: RE
authors.lastname: Welsh
authors.forename: Jianguo
authors.initials: J
authors.lastname: Qian
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Weisenberger
authors.forename: Mark F
authors.initials: MF
authors.lastname: Smith
authors.forename: Stan
authors.initials: S
authors.lastname: Majewski
authors.forename: Margaret S
authors.initials: MS
authors.lastname: Saha
mesh_terms: D000284:Administration, Oral; D000818:Animals; D015902:Gamma Cameras; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D011193:Potassium Iodide / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011833:Radiation Injuries, Experimental / Q000517:prevention & control / Q000662:veterinary; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D014018:Tissue Distribution / Q000187:drug effects* / Q000502:physiology; D014915:Whole-Body Counting
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D011193:Potassium Iodide