When pregnancy is discovered during or after a diagnostic examination, the physician or the patient may request an estimate of the radiation dose received by the fetus as per guidelines and standard operating procedures. This study provided the imaging community with dose estimates to the fetus from PET/CT with protocols that are adapted to University of Michigan low-dose protocols for patients known to be pregnant. Methods: There were 9 patients analyzed with data for the first, second, and third trimesters, the availability of which is quite rare. These images were used to calculate the size-specific dose estimate (SSDE) from the CT scan portion and the SUV and ¹⁸F-FDG uptake dose from the PET scan portion using the MIRD formulation. The fetal dose estimates were tested for correlation with each of the following independent measures: gestational age, fetal volume, average water-equivalent diameter of the patient along the length of the fetus, SSDE, SUV, and percentage of dose from ¹⁸F-FDG. Stepwise multiple linear regression analysis was performed to assess the partial correlation of each variable. To our knowledge, this was the first study to determine fetal doses from CT and PET images. Results: Fetal self-doses from ¹⁸F for the first, second, and third trimesters were 2.18 mGy (single data point), 0.74–1.82 mGy, and 0.017–0.0017 mGy, respectively. The combined SSDE and fetal self-dose ranged from 1.2 to 8.2 mGy. These types of images from pregnant patients are rare. Conclusion: Our data indicate that the fetal radiation exposure from ¹⁸F-FDG PET and CT performed, when medically necessary, on pregnant women with cancer is low. All efforts should be made to minimize fetal radiation exposure by modifying the protocol.

当在诊断检查期间或之后发现怀孕时，医生或患者可能会根据指南和标准操作程序要求估计胎儿接受的辐射剂量。这项研究为成像界提供了 PET/CT 对胎儿的剂量估计，其方案适用于密歇根大学针对已知怀孕患者的低剂量方案。方法：对 9 名患者的第一、第二和第三个三个月的数据进行了分析，这些数据的可用性非常罕见。这些图像用于计算 CT 扫描部分和 SUV 的尺寸特异性剂量估计值 (SSDE) 和¹⁸使用 MIRD 配方从 PET 扫描部分摄取的 F-FDG 剂量。测试了胎儿剂量估计值与以下每个独立测量值的相关性：胎龄、胎儿体积、患者沿胎儿长度的平均水当量直径、SSDE、SUV 和 18 F-FDG 的^剂量百分比. 进行逐步多元线性回归分析以评估每个变量的偏相关性。据我们所知，这是第一项根据 CT 和 PET 图像确定胎儿剂量的研究。结果：来自^{18 岁的}胎儿自我剂量第一、第二和第三个三个月的 F 分别为 2.18 mGy（单个数据点）、0.74–1.82 mGy 和 0.017–0.0017 mGy。合并的 SSDE 和胎儿自身剂量范围为 1.2 至 8.2 mGy。这些来自孕妇的图像很少见。结论：我们的数据表明，在医学上必要时，对患有癌症的孕妇进行的¹⁸ F-FDG PET 和 CT胎儿辐射暴露较低。应尽一切努力通过修改协议来尽量减少胎儿的辐射暴露。