Department of Radiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA.
Pediatr Radiol. 2023 Sep;53(10):2054-2059. doi: 10.1007/s00247-023-05715-5. Epub 2023 Jul 10.
Only verbal pregnancy screening is recommended for post-menarcheal females undergoing pelvic radiographs. In contrast, usually, a urine/serum pregnancy test for pelvic computed tomographic (CT) exams is required out of concern for higher radiation exposure.
To estimate patient-specific fetus absorbed dose to a potentially pregnant minor from an optimized dose CT of the pelvis for femoral version and surgical planning and provide evidence that such examinations of the pelvis can be performed with only verbal pregnancy screening.
A retrospective study was performed on 102 female patients between 12-18 years of age (15.4 ± 2.1 years) who underwent optimized dose CT of the pelvis for orthopedic evaluation of femoral version and surgical planning. Optimized CT exams were performed with weight-adjusted kVp and tube current modulation. Patient-specific dose from the optimized dose CT was calculated using the National Cancer Institute Dosimetry System for CT (NCICT) database by matching each patient to a phantom from the NCI non-reference phantom library based on patient sex, weight, and height. The calculated absorbed uterus dose was used as a surrogate for the fetus dose. Furthermore, patient-specific organ doses were used to estimate the effective dose. The strengths of the linear relationships between the dose metrics and patient characteristics were assessed using Pearson correlation coefficients through linear regression.
The mean patient-specific effective dose for an optimized dose CT of the pelvis was 0.54 ± 0.20 mSv (range: 0.15-1.22 mSv). The mean estimated absorbed uterine dose was 1.57 ± 0.67 mGy (range: 0.42-4.81 mGy). Both effective dose and estimated uterine dose correlated poorly with patient physical characteristics (R = -0.26; 95% CI: [-0.43, -0.007] for age, R = 0.03; 95% CI: [-0.17, 0.22] for weight) but correlated strongly (R = 0.79, 95% CI: [0.7, 0.85]) with CTDI.
The estimated fetus dose in case of pregnancy was significantly lower than 20 mGy for urine/serum pregnancy screening, suggesting that the pregnancy screening protocols in minors undergoing optimized dose CT require reassessment and may be safely performed by verbal attestation only.
对于进行骨盆 X 光检查的青春期后女性，仅推荐口头妊娠筛查。相比之下，出于对更高辐射暴露的担忧，通常需要对进行骨盆计算机断层扫描（CT）检查的患者进行尿液/血清妊娠检测。
评估潜在妊娠未成年患者接受骨盆优化剂量 CT 检查（用于股骨旋转评估和手术计划）的胎儿特定吸收剂量，并提供证据表明，仅通过口头妊娠筛查即可进行此类骨盆检查。
对 102 名 12-18 岁（15.4±2.1 岁）的女性患者进行了回顾性研究，这些患者因股骨旋转和手术计划的骨科评估而接受了骨盆优化剂量 CT 检查。优化 CT 检查使用体重调整的 kVp 和管电流调制进行。使用国家癌症研究所 CT 剂量系统（NCICT）数据库通过将每位患者与 NCI 非参考体模库中的体模相匹配，根据患者性别、体重和身高，计算每位患者的优化剂量 CT 的患者特异性剂量。计算出的子宫吸收剂量被用作胎儿剂量的替代物。此外，使用患者特异性器官剂量来估计有效剂量。通过线性回归，使用 Pearson 相关系数评估剂量指标与患者特征之间的线性关系强度。
骨盆优化剂量 CT 的平均患者特异性有效剂量为 0.54±0.20mSv（范围：0.15-1.22mSv）。估计的子宫吸收剂量平均值为 1.57±0.67mGy（范围：0.42-4.81mGy）。有效剂量和估计的子宫剂量与患者的身体特征相关性均较差（年龄的 R 为-0.26；95%置信区间：[-0.43，-0.007]，体重的 R 为 0.03；95%置信区间：[-0.17，0.22]），但与 CTDI 相关性较强（R 为 0.79，95%置信区间：[0.7，0.85]）。
如果妊娠，胎儿剂量明显低于尿液/血清妊娠检测的 20mGy，这表明接受优化剂量 CT 检查的未成年患者的妊娠筛查方案需要重新评估，并且仅通过口头证明即可安全进行。
