Lynne Hurwitz MD, Presenter: Nothing to Disclose

Terry T. Yoshizumi PhD, Abstract Co-Author: Nothing to Disclose

Donald Paul Frush MD, Abstract Co-Author: Nothing to Disclose

Erik Karl Paulson MD, Abstract Co-Author: Nothing to Disclose

Robert Reiman MD, Abstract Co-Author: Nothing to Disclose

Greta Toncheva BS, Abstract Co-Author: Nothing to Disclose

Giao Nguyen, Abstract Co-Author: Nothing to Disclose

Lottie Barnes, Abstract Co-Author: Nothing to Disclose

Philip Cary Goodman MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

The conventional approach for estimating radiation dose to the fetus from computed tomography (CT) is to use the CT dose index (CTDI) combined with other information. Current CTDI defined by the US FDA is no longer applicable in modern multidetector helical CT (MDCT) scanners. Thus, existing methods have serious limitation when applied to MDCT scanners. The purpose of this project was: (1) To fabricate pregnant phantoms at 0 and 3 month gestational ages as these are the developmental ages most sensitive to radiation induced mental retardation and developmental disorders (2) to measure associated maternal breast dose and (3) to apply real time MOSFET detector technology in MDCT enviroment.

An adult female anthropomorphic phantom (CIRS, Inc. Norfolk, VA) was employed. Landmarks for uterine location and shape for 0 and 3 months were determined using the MIRD pregnant woman phantoms (Oak Ridge, TN). Both MOSFET and TLD dosimeters were placed at appropriate locations to monitor radiation dose to the fetus and the maternal breast. MDCT (Lightspeed GEMS) was performed for evaluation of renal stone (140 kVp, 340 mAs, 16 x 0.625, 5mm thickness), appendix (140 kVp, 340 mAs, 16 x 0.625, 5mm thickness) and pulmonary embolus (140 kVp, 380 mAs, 16 x 0.625, 1.25 mm thickness).

Radiation doses to fetus at 0 and 3 months were as follows:renal stone CT was 0.8-1.2 cGy and 0.4-0.7 cGy and appendix CT was 1.5-1.6 cGy and 2-4 cGy. Pulmonary embolus CT was 0.024-0.048 cGy at 0 months and 0.062-0.067 cGy at 3 months. Using the PE CT protocol, the breast radiation dose was approximately 3-5 cGy.

(1) Phantom successfully used to model pregnancy at 0 and 3 months fetal gestation. (2) Using body MDCT protocols, radiation dose to the fetus during the first trimester is less than that thought to place the fetus at risk for neurological or other developmental disorders (>10cGy). (3) Radiation dose to the breast from pulmonary embolus CT is significantly higher than that of a V/Q scan, and utilization of pulmonary embolus CT should be carefully considered during pregnancy. (4) MOSFET detectors have demonstrated the advantage of estimating radiation dose in real time.

Hurwitz, L, Yoshizumi, T, Frush, D, Paulson, E, Reiman, R, Toncheva, G, Nguyen, G, Barnes, L, Goodman, P, et al, , Development of Pregnant Anthropomorphic Phantom for (MOSFET) Assessment of Maternal and Fetal Doses during Body MDCT.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4404004.html