Institute of Radiation Medicine, Fudan University, No. 2094, Xietu Road, Shanghai, 200032, PR China.
Health Phys. 2013 Aug;105(2):187-91. doi: 10.1097/HP.0b013e318290cc0e.
Widely used release criteria for patients receiving radiopharmaceuticals (NUREG-1556, Vol. 9, Rev.1, Appendix U) are known to be overly conservative. The authors measured external exposure rates near patients treated with I, Tc, and F and compared the measurements to calculated values using point and line source models. The external exposure dose rates for 231, 11, and 52 patients scanned or treated with I, Tc, and F, respectively, were measured at 0.3 m and 1.0 m shortly after radiopharmaceutical administration. Calculated values were always higher than measured values and suggested the application of "self-shielding factors," as suggested by Siegel et al. in 2002. The self-shielding factors of point and line source models for I at 1 m were 0.60 ± 0.16 and 0.73 ± 0.20, respectively. For Tc patients, the self-shielding factors for point and line source models were 0.44 ± 0.19 and 0.55 ± 0.23, and the values were 0.50 ± 0.09 and 0.60 ± 0.12, respectively, for F (all FDG) patients. Treating patients as unshielded point sources of radiation is clearly inappropriate. In reality, they are volume sources, but treatment of their exposures using a line source model with appropriate self-shielding factors produces a more realistic, but still conservative, approach for managing patient release.
广泛应用于接受放射性药物治疗的患者的释放标准（NUREG-1556，第 9 卷，修订版 1，附录 U）被认为过于保守。作者测量了接受 I、Tc 和 F 治疗的患者附近的体外照射率，并将测量值与使用点源和线源模型计算的值进行了比较。分别对 231、11 和 52 名接受 I、Tc 和 F 扫描或治疗的患者，在放射性药物给药后不久，在 0.3m 和 1.0m 处测量了体外照射剂量率。计算值始终高于测量值，并提示应用 Siegel 等人于 2002 年提出的“自屏蔽因子”。在 1m 处，I 的点源和线源模型的自屏蔽因子分别为 0.60±0.16 和 0.73±0.20。对于 Tc 患者，点源和线源模型的自屏蔽因子分别为 0.44±0.19 和 0.55±0.23，对于所有 FDG 患者，自屏蔽因子分别为 0.50±0.09 和 0.60±0.12。将患者视为无屏蔽的放射源显然是不合适的。实际上，他们是体积源，但使用具有适当自屏蔽因子的线源模型来处理他们的暴露，可以为管理患者释放提供一种更现实但仍然保守的方法。
