Biomaterial Database

Estimates of embryonic and fetal doses from 239Pu. 1992

A Morgan, and J D Harrison, and J W Stather

National Radiological Protection Board, Didcot, Oxon.

Previously reported studies on the transfer of 238Pu from the maternal circulation to the developing embryo and fetus in rats and guinea pigs have provided data for developing dosimetric models. The highest concentrations of 238Pu were measured in the yolk sac. In late gestation, preferential uptake of 238Pu in liver and bone was observed. The data obtained, together with other published information, have been used to estimate in utero doses to hemopoietic tissues, taking account of transfer to the blastocyst/egg cylinder, yolk sac, liver, and bone marrow. From animal data, the concentration ratios relative to maternal liver for these tissues were taken to be 0.1, 2, 0.01, and 0.02, respectively, and were applied to periods of human gestation of 0-2.5 wk, 2.5-6 wk, 6-12 wk, and 12-38 wk, respectively. Doses to fetal tissues from 239Pu were calculated for chronic ingestion by the mother for a total of 1.8 kBq 239Pu during the year of pregnancy, giving a committed effective dose to the mother of 1 mSv. On this basis, the total in utero dose to hemopoietic tissue was about 2 microSv compared with red bone marrow doses of 34 microSv to the mother for the year. The yolk sac and bone marrow dominated in utero doses. The total dose to hemopoietic tissue in the offspring to age 70 y, taking into account the activity present at birth and including in utero doses, was estimated as 24 microSv compared with a maternal dose to red bone marrow of 2.5 mSv. An acute maternal intake of 1.8 kBq by ingestion during the period of yolk sac hemopoiesis would result in the highest in utero dose, estimated at about 36 microSv. However, activity at birth would be lower, giving only a small additional dose.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008431	Maternal-Fetal Exchange	Exchange of substances between the maternal blood and the fetal blood at the PLACENTA via PLACENTAL CIRCULATION. The placental barrier excludes microbial or viral transmission.	Transplacental Exposure,Exchange, Maternal-Fetal,Exposure, Transplacental,Maternal Fetal Exchange
D011005	Plutonium	A naturally radioactive element of the actinide metals series. It has the atomic symbol Pu, and atomic number 94. Plutonium is used as a nuclear fuel, to produce radioisotopes for research, in radionuclide batteries for pacemakers, and as the agent of fission in nuclear weapons.
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D004622	Embryo, Mammalian	The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.	Embryonic Structures, Mammalian,Mammalian Embryo,Mammalian Embryo Structures,Mammalian Embryonic Structures,Embryo Structure, Mammalian,Embryo Structures, Mammalian,Embryonic Structure, Mammalian,Embryos, Mammalian,Mammalian Embryo Structure,Mammalian Embryonic Structure,Mammalian Embryos,Structure, Mammalian Embryo,Structure, Mammalian Embryonic,Structures, Mammalian Embryo,Structures, Mammalian Embryonic
D005260	Female		Females
D005314	Embryonic and Fetal Development	Morphological and physiological development of EMBRYOS or FETUSES.	Embryo and Fetal Development,Prenatal Programming,Programming, Prenatal
D005333	Fetus	The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.	Fetal Structures,Fetal Tissue,Fetuses,Mummified Fetus,Retained Fetus,Fetal Structure,Fetal Tissues,Fetus, Mummified,Fetus, Retained,Structure, Fetal,Structures, Fetal,Tissue, Fetal,Tissues, Fetal
D005865	Gestational Age	The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated from the onset of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization. It is also estimated to begin from fertilization, estrus, coitus, or artificial insemination.	Embryologic Age,Fetal Maturity, Chronologic,Chronologic Fetal Maturity,Fetal Age,Maturity, Chronologic Fetal,Age, Embryologic,Age, Fetal,Age, Gestational,Ages, Embryologic,Ages, Fetal,Ages, Gestational,Embryologic Ages,Fetal Ages,Gestational Ages