SPECIFIC ABSORBED FRACTIONS FOR INTERNAL PHOTON EMITTERS CALCULATED FOR A TOMOGRAPHIC MODEL OF A PREGNANT WOMAN

• Published in: Health physics (1958) Vol. 87; no. 5; pp. 507 - 511
• Main Authors: Shi, C Y, Xu, X G, Stabin, M G
• Format: Journal Article
• Language: English
• Published: United States Health Physics Society 01-11-2004; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Algorithms; Atoms & subatomic particles; Body Burden; Computer Simulation; Female; Humans; Linear Energy Transfer; Maternal Exposure; Models, Biological; Organ Specificity; Photons; Pregnancy; Radiation; Radiation Dosage; Radiation Protection - methods; Radiometry - methods; Relative Biological Effectiveness; Risk Assessment - methods; Tomography, X-Ray Computed - methods; Whole-Body Counting - methods
• ISSN: 0017-9078; 1538-5159
• DOI: 10.1097/01.HP.0000133364.55155.09

Specific absorbed fractions are essential for calculation of radiation dose from internal emitters. Existing specific absorbed fractions for pregnant women were calculated using the stylized models; in this work, a partial-body tomographic model for a pregnant woman was constructed from a rare set of CT images. Based on this tomographic model, the Monte Carlo code, EGS4-VLSI, was used to derive specific absorbed fractions. Monoenergetic, isotropic photon emitters from 15 keV to 4 MeV were distributed in different source organs, and doses were calculated to many target regions in the body. Even though the results showed general agreement with previous studies for higher energies, significant differences were also found, especially for lower energies. The main reasons for the differences are due to the variation of mass, geometry, and organ distances, and they demonstrate the influence of more realistic body models on dose calculations.