Determination of age specific ¹³¹I S-factor values for thyroid using anthropomorphic phantom in Geant4 simulations

Appl Radiat Isot. 2014 Aug:90:15-22. doi: 10.1016/j.apradiso.2014.03.004. Epub 2014 Mar 12.

Abstract

Using anthropomorphic phantom in Geant4, determination of β- and γ-absorbed fractions and energy absorbed per event due to (131)I activity in thyroid of individuals of various age groups and geometrical models, have been carried out. In the case of (131)I β-particles, the values of the absorbed fraction increased from 0.88 to 0.97 with fetus age. The maximum difference in absorbed energy per decay for soft tissue and water is 7.2% for γ-rays and 0.4% for β-particles. The new mathematical MIRD embedded in Geant4 (MEG) and two-lobe ellipsoidal models developed in this work have 4.3% and 2.9% lower value of S-factor as compared with the ORNL data.

Keywords: Anthropomorphic phantom; Geant4 simulations; Iodine-131; S-factor values; Thyroid.

MeSH terms

  • Absorption, Radiation
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / metabolism*
  • Anthropometry / methods*
  • Child
  • Child, Preschool
  • Computer Simulation
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Iodine Radioisotopes / pharmacokinetics*
  • Male
  • Middle Aged
  • Models, Biological*
  • Organ Specificity
  • Radiation Dosage
  • Radiometry / methods*
  • Radiopharmaceuticals / pharmacokinetics
  • Software*
  • Thyroid Gland / metabolism*
  • Young Adult

Substances

  • Iodine Radioisotopes
  • Radiopharmaceuticals