Han Eun Young, Lee Choonsik, Mcguire Lynn, Bolch Wesley E
Department of Radiation Oncology, University of Arkansas Medical Sciences, AR, USA.
J Radiol Prot. 2014 Jun;34(2):N7-17. doi: 10.1088/0952-4746/34/2/N7. Epub 2014 Apr 4.
We recently published effective doses per time-integrated activity (mSv MBq(-1) s(-1)) for paediatric and adult family members exposed to an adult patient released from hospital following I-131 therapy. In the present study, we intend to provide medical physicists with a methodology to estimate family member effective dose in daily clinical practice because the duration of post-radiation precautions for the patient-family member exposure scenario has not been explicitly delineated based on the effective dose. Four different exposure scenarios are considered in this study including (1) a patient and a family member standing face to face, (2) a patient and a family member lying side by side, (3) an adult female patient holding a newborn child to her chest and (4) a one-year-old child standing on the lap of an adult female patient following her I-131 therapy. The results of this study suggest that an adult female hyperthyroidism (HT) patient who was administered with 740 MBq should keep a distance of 100 cm from a 15-year-old child for six days and the same distance from other adults for seven days. The HT female patient should avoid holding a newborn against her chest for at least 16 days following hospital discharge, and a female patient treated with 5550 MBq for differentiated thyroid cancer should not hold her newborn child for at least 15 days following hospital discharge. This study also gives dose coefficients allowing one to predict age-specific effective doses to family members given the measured dose rate (mSv h(-1)) of the patient. In conclusion, effective dose-based patient release criteria with a modified NRC two-component model provide a site medical physicist with less restrictive and age-specific radiation precaution guidance as they fully consider a patient's iodine biokinetics and photon attenuation within both the patient and the exposed family members.
我们最近公布了接受碘 - 131治疗后出院的成年患者周围的儿科和成年家庭成员每时间积分活度的有效剂量（毫希沃特·兆贝可勒尔⁻¹·秒⁻¹）。在本研究中，我们旨在为医学物理学家提供一种在日常临床实践中估算家庭成员有效剂量的方法，因为基于有效剂量，患者 - 家庭成员暴露场景的辐射后防护持续时间尚未明确界定。本研究考虑了四种不同的暴露场景，包括：（1）患者与家庭成员面对面站立；（2）患者与家庭成员并排躺卧；（3）成年女性患者将新生儿抱在胸前；（4）成年女性患者接受碘 - 131治疗后，一岁儿童站在其腿上。本研究结果表明，接受740兆贝可勒尔治疗的成年女性甲状腺功能亢进（HT）患者应与15岁儿童保持100厘米的距离6天，与其他成年人保持相同距离7天。HT女性患者出院后应避免将新生儿抱在胸前至少16天，接受5550兆贝可勒尔治疗的分化型甲状腺癌女性患者出院后应避免抱新生儿至少15天。本研究还给出了剂量系数，可根据患者的测量剂量率（毫希沃特·小时⁻¹）预测特定年龄的家庭成员有效剂量。总之，基于有效剂量的患者出院标准以及改进的美国核管理委员会双组分模型，为现场医学物理学家提供了限制较少且针对特定年龄的辐射防护指导，因为它们充分考虑了患者的碘生物动力学以及患者和受暴露家庭成员体内的光子衰减。
