title: Fetal radiation dose in computed tomography.
abstract: The connection between recorded volumetric CT dose index (CTDI vol) and determined mean fetal dose (Df) was examined from metal-oxide-semiconductor field-effect transistor dose measurements on an anthropomorphic female phantom in four stages of pregnancy in a 64-slice CT scanner. Automated tube current modulation kept the mean Df fairly constant through all pregnancy stages in trauma (4.4-4.9 mGy) and abdomino-pelvic (2.1-2.4 mGy) protocols. In pulmonary angiography protocol, the mean Df increased exponentially as the distance from the end of the scan range decreased (0.01-0.09 mGy). For trauma protocol, the relative mean Df as a function of gestational age were in the range 0.80-0.97 compared with the mean CTDI vol. For abdomino-pelvic protocol, the relative mean Df was 0.57-0.79 and for pulmonary angiography protocol, 0.01-0.05 compared with the mean CTDI vol, respectively. In conclusion, if the fetus is in the primary beam, the CTDI vol can be used as an upper estimate of the fetal dose. If the fetus is not in the primary beam, the fetal dose can be estimated by considering also the distance of the fetus from the scan range.
authors.affiliation: HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, PO Box 340, FI-00290 Helsinki, Finland Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland anna.kelaranta@alumni.helsinki.fi.
authors.forename: Anna
authors.initials: A
authors.lastname: Kelaranta
authors.affiliation: HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, PO Box 340, FI-00290 Helsinki, Finland Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland.
authors.forename: Touko
authors.initials: T
authors.lastname: Kaasalainen
authors.affiliation: HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, PO Box 340, FI-00290 Helsinki, Finland.
authors.forename: Raija
authors.initials: R
authors.lastname: Seuri
authors.affiliation: STUK - Radiation and Nuclear Safety Authority, Laippatie 4, PO Box 14, FI-00881 Helsinki, Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Toroi
authors.affiliation: HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, PO Box 340, FI-00290 Helsinki, Finland Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Kortesniemi
mesh_terms: D000792:Angiography / Q000009:adverse effects; D000886:Anthropometry; D002138:Calibration; D003198:Computer Simulation; D005260:Female; D005333:Fetus / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D018811:Maternal Exposure; D008670:Metals / Q000737:chemistry; D009010:Monte Carlo Method; D010087:Oxides / Q000737:chemistry; D019047:Phantoms, Imaging; D011247:Pregnancy; D011829:Radiation Dosage; D000069079:Radiation Exposure; D012666:Semiconductors; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000009:adverse effects*
chemical_list: D008670:Metals; D010087:Oxides