[Prenatal Radiation Exposure in Nuclear Medicine]

Radiation exposure from nuclear medicine procedures during pregnancy may cause uncertainty among patients and medical professionals. In 2019, the German Society of Medical Physics (DGMP) and the German Society of Radiology (DRG) published a fully revised version of the report "Prenatal Radiation Exposure Arising from Medical Indication, Dose Calculation, Conclusions for Physicians and Pregnant Women". This report offers a basis for dose calculation and determination of radiation exposure to the unborn. This review summarizes the most notable general adaptions made in the report's newest version and specifically points out the changes relevant to the field of nuclear medicine.The DGMP report provides physicians and medical physicists with means to estimate prenatal radiation exposure to the unborn conservatively, in a prompt and comprehensible approach. The rapidly evolving field of indications in nuclear medicine and radiology gave rise to the initiative of profoundly revising the previous version of the report from 2002. It now accounts for the extended range of devices, nuclear medicine hybrid imaging and radiotracers recently introduced. The most extensive change is a shift from the former 3-step-concept for the dose calculation to a 2-step-concept. In diagnostic nuclear medicine the first step comprises a conservative approximation of radiation exposure on the basis of current diagnostic reference levels (DRL). If exposure is assessed to be below 20 mSv, risk to the unborn child is sufficiently low, no further approaches are considered necessary. If calculated doses exceed 20 mSv, for diagnostic studies without existing DRL or in case of radionuclide therapies step 2 requires dose calculation based on administered activity and the stage of pregnancy.The DGMP report on prenatal radiation exposure offers valuable guidance for physicians and medical physicists in the field of nuclear medicine. The calculation concept provides an important basis to estimate radiation exposure to the unborn. Its extensive revision in 2019 accounts for recent scientific and technical developments and a reform of the stepwise approach to dose estimation.