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Radiation and Pregnancy. ©Health Physics Society. Medical X-Ray Exams. Radiation exposure that is extra-abdominal will not contribute significant radiation dose to the developing embryo/fetus.
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Radiation and Pregnancy ©Health Physics Society
Medical X-Ray Exams • Radiation exposure that is extra-abdominal will not contribute significant radiation dose to the developing embryo/fetus. • For most extra-abdominal exams, including CT, the radiation dose to the embryo/fetus is less than 0.1 mSv (10 mrem).
Medical X-Ray Exams Abdomen Exposed • Uterus estimated doses1 – typical values • Upper GI 1 mSv (0.1 rem) • L-spine 4 mSv (0.4 rem) • Pelvis 2 mSv (0.2 rem) • Hips/Upper femur 3 mSv (0.3 rem) • Abdomen 2.5 mSv (0.25 rem) • Barium enema 10 mSv (1.0 rem) • IVP 6 mSv (0.6 rem) • Abdominal CT 30 mSv (3.0 rem) 1Estimated doses can vary significantly, especially when fluoroscopy is used. Adapted from Wagner, et al. Exposure of the pregnant patient to diagnostic radiations. 1997.
Nuclear Medicine Exams • Most of the radiopharmaceuticals used will cross the placental barrier. • In general, the conceptus dose from most diagnostic nuclear medicine exams, other than the radioiodines, will be less than 10 mSv (1 rem). Adapted from Wagner, et al. Exposure of the pregnant patient to diagnostic radiations. 1997.
Nuclear Medicine Exams • Doses to conceptus from sodium 131iodide: • Thyroid • Less than 8 or 9 weeks: thyroid not functional • 3-5 months: 0.26-0.64 Sv to conceptus from one MBq administered to mother (960-2,400 rem/mCi) • 6-9 months: 0.43-0.84 Sv to conceptus from one MBq administered to mother (1,600-3,100 rem/mCi) • Whole Body • Less than 3 months: 27-310 µSv to conceptus from one MBq administered to mother (0.1-1.15 rem/mCi) • 3-9 months: <55 µSv to conceptus from one MBq administered to mother (<0.2 rem/mCi) Adapted from Wagner, et al. Exposure of the pregnant patient to diagnostic radiations. 1997.
Radiation and Pregnancy Talking Points(if conceptus exposure occurred)
Talking Points • Childhood cancer from in utero exposure • Likelihood of not developing cancer with no radiation exposure is 99.93 percent. • Likelihood of not developing cancer with a 50 mSv (5 rem) dose is 99.12 percent. • Conclusion: the chance of developing childhood cancer due to in utero radiation exposure from most medical exams is theoretical. Adapted from Wagner, et al. Exposure of the pregnant patient to diagnostic radiations. 1997.
Talking Points • “Specifically, exposure to less than 50 mSv (5 rem) has not been associated with an increase in fetal anomalies or pregnancy loss.” American College of Obstetricians and Gynecologists Policy 299. 2004.
Talking Points • The general population’s total risk of spontaneous abortion, major malformation, mental retardation, and childhood malignancy for a given pregnancy is just under 30 percent. • Statistically, 3 in 10 pregnancies will result in an adverse outcome with no additional radiation exposure. • A radiation dose of 50 mSv (5 rem) increases this by about 0.17 percent. Brent RL. Utilization of developmental basic science principles in the evaluation of reproductive risks from pre- and postconception environmental radiation exposure. Teratology 59:182; 1999.
Talking Points • “The risk of abnormality is considered to be negligible at 50 mSv (5 rem) or less when compared to other risks of pregnancy.” • “The risk of malformation is increased only at levels above 150 mSv (15 rem).” Adapted from NCRP Report 54. Medical exposure of pregnant and potentially pregnant women. 1977.
Talking Points • If the radiation dose is received between the second and eighth post-conception weeks, therapeutic abortion based solely on radiation exposure is not advised for doses less than 150 mSv (15 rem). Adapted from Wagner, et al. Exposure of the pregnant patient to diagnostic radiations. 1997.
Disclaimer In our efforts to create an understandable, easy to read and use program, we have chosen to use the radiation effective dose terms rem or sievert. In some case, for technical precision, the radiation absorbed dose terms rad or gray may be most appropriate. We do not believe that scientific accuracy is lost because of our choice of dose term.
