Dosimetric data for the fetus derived from an anatomical model of its mother at the end of the first trimester
We discuss a study of the radiation transport of monoenergetic photons within a mathematical phantom of the pregnant female at the end of the first trimester. This phantom was developed from the adult female member of the ORNL phantom series with modifications reflecting anatomical changes at this stage of pregnancy. This geometry was incorporated into the ALGAMP Monte Carlo radiation transport code used at ORNL with the phantom series. For internal sources of radiation the emission of 60,000 monoenergetic photons at each of 12 energies within 30 organs of the body was simulated. Energy deposition within 158 regions of the body, including uterine wall, uterine contents, and 12 subregions within the contents, was tabulated. The results are presented in terms of the specific absorbed fraction, i.e., the fraction of the photon energy emitted within a source organ that is absorbed per unit mass of the target region. The specific absorbed fraction data are commonly used to evaluate the dose associated with internal emitters, e.g., from administered radiopharmaceuticals. Additional calculations have been performed for a uniform, isotropic field of photons incident on the surface of the phantom; these data provide information on the shielding of the fetus by the mother and are of interest in evaluation of doses from external radiation fields. In this study we have provided dosimetric information useful in making quantitative risk estimates for the developing fetus. Our investigations demonstrate that even at this early stage in pregnancy the effective dose equivalent to the mother cannot be used as an index of the dose equivalent to the fetus. Further efforts will be directed to consideration of later stages in fetal development and consideration of irradiation by external neutron fields.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Tennessee Univ., Chattanooga (USA). Dept. of Physics; Oak Ridge Associated Universities, Inc., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7183093
- Report Number(s):
- CONF-861123-1; ON: DE87003009
- Resource Relation:
- Conference: CEC/CEA international workshop on age-related factors in radionuclide metabolism and dosimetry, Angers, France, 26 Nov 1986; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FETUSES
RADIATION DOSES
PREGNANCY
PHANTOMS
ENERGY TRANSPORT
EXTERNAL IRRADIATION
INTERNAL IRRADIATION
MATHEMATICAL MODELS
PHOTON TRANSPORT
PRENATAL IRRADIATION
WOMEN
ANIMALS
DOSES
FEMALES
IRRADIATION
MAMMALS
MAN
MOCKUP
NEUTRAL-PARTICLE TRANSPORT
PRENATAL EXPOSURE
PRIMATES
RADIATION TRANSPORT
STRUCTURAL MODELS
VERTEBRATES
655003* - Medical Physics- Dosimetry