title: Examination of the effect of counting geometry on 125I monitoring using MCNP.
abstract: This paper theoretically investigates how the counting efficiencies of three selected detector (NaI) sizes are affected by neck-detector distance, detector misplacement, thickness of overlaying tissue, and size of the thyroid gland. The detector sizes were small, 2.54 cm diameter and 0.2 cm crystal thickness; medium, 7.62 cm diameter and 0.2 cm crystal thickness; large 30.48 cm diameter and 0.2 cm crystal thickness. The evaluations were determined using a Monte Carlo technique. The simulations show that the large detector minimizes the uncertainties for all problems except the thickness of overlaying tissue.
authors.affiliation: Radiation Protection Bureau, Ottawa, Ontario, Canada.
authors.forename: G H
authors.initials: GH
authors.lastname: Kramer
authors.forename: S
authors.initials: S
authors.lastname: Yiu
mesh_terms: D006801:Humans; D007457:Iodine Radioisotopes / Q000032:analysis*; D008961:Models, Structural; D009010:Monte Carlo Method; D009333:Neck; D009929:Organ Size; D011879:Radiotherapy Dosage; D012974:Sodium Iodide; D013961:Thyroid Gland / Q000033:anatomy & histology
chemical_list: D007457:Iodine Radioisotopes; D012974:Sodium Iodide