title: Evaluation of systematic errors in thyroid monitoring.
abstract: In this manuscript the thyroid is described by a new model. Efficiencies of a NaI(Tl) detector, for 364 keV photons, are calculated using Monte Carlo simulation. Contributions from thyroid size, detector placement and tissue overlay thickness, to the efficiency uncertainty, are evaluated considering the thyroid of a 12 year old subject as a limit for the adult thyroid. For a shielded 3" x 3" NaI(Tl) detector, placed at 20 cm from the neck, a contribution of 18% to the efficiency uncertainty was found.
authors.affiliation: Instituto de Pesquisas Energéticas e Nucleares, Departamento de Metrologia das Radiações (NM), C. P. 11049, CEP 05422-970 Pinheiros, São Paulo, Brazil. lventur@net.ipen.br
authors.forename: L
authors.initials: L
authors.lastname: Venturini
mesh_terms: D000328:Adult; D000535:Aluminum; D002138:Calibration; D002648:Child; D003198:Computer Simulation; D005720:Gamma Rays; D006801:Humans; D007454:Iodides / Q000528:radiation effects; D007457:Iodine Radioisotopes; D019300:Medical Errors; D008875:Middle Aged; D009010:Monte Carlo Method; D009333:Neck / Q000033:anatomy & histology / Q000254:growth & development; D016273:Occupational Exposure; D009929:Organ Size; D012964:Sodium / Q000528:radiation effects; D013793:Thallium / Q000528:radiation effects; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000254:growth & development / Q000528:radiation effects*; D014132:Trachea / Q000033:anatomy & histology / Q000254:growth & development
chemical_list: D007454:Iodides; D007457:Iodine Radioisotopes; C477364:thallium-doped sodium iodide; D012964:Sodium; D013793:Thallium; D000535:Aluminum