Abstract：
18F has been the most widely used radionuclide in positron emission tomography (PET) facilities over the last few decades. However, increased interest in novel PET tracers, theranostics and immuno-PET has led to significant growth in clinically used positron-emitting radionuclides. The decay schemes of each of these radioisotopes are markedly different from18F, with different endpoint energies for the emitted positrons and, in some cases, additional high energy gamma radiation. This has implications for the occupational exposure of personnel involved in the manipulation and dispensing of PET radiopharmaceuticals. The EGSnrc Monte Carlo simulation software was used to estimate the doses to extremities in contact with unshielded and shielded syringes containing64Cu,18F,11C,13N,15O,68Ga and89Zr, respectively. Dose rates at various distances from the syringe were also modelled, with dose rates reported in terms of eye (Hp(3)), skin equivalent (Hp(0.07)) and deep (Hp(10)) doses. The composition and geometry of the simulated syringe shields were based on a selection of commercially available PET shields. Experimental dose rate measurements were performed for validation purposes where possible. Contact skin dose rates for all isotopes, except for64Cu, were found to be higher than18F for the unshielded syringe. The addition of a shield resulted in approximately equal contact skin dose rates for nearly all isotopes, for each shield type, with the exception of89Zr which was notably higher. Dose rate constants (µGy/MBq.hr) for a range of PET isotopes and shields are presented and their significance discussed.
摘要：
在过去的几十年中，18F一直是正电子发射断层扫描（PET）设施中使用最广泛的放射性核素。然而,对新型PET示踪剂的兴趣增加，Theranosics和免疫PET已导致临床上使用的正电子发射放射性核素的显着增长。这些放射性同位素的衰变方案与18F明显不同，发射的正电子具有不同的端点能量，在某些情况下,额外的高能伽马辐射。这对参与PET放射性药物的操作和分配的人员的职业暴露具有影响。EGSnrcMonteCarlo模拟软件用于估算与含有64Cu的非屏蔽和屏蔽注射器接触的四肢剂量。18F,11C,13N,15O,68Ga和89Zr，分别。还模拟了距注射器不同距离的剂量率，以眼睛报告的剂量率(Hp(3))，皮肤当量（Hp（0.07））和深（Hp（10））剂量。模拟注射器护罩的组成和几何形状基于市售PET护罩的选择。在可能的情况下进行实验剂量率测量以用于验证目的。所有同位素的接触皮肤剂量率，除了for64Cu，发现未屏蔽注射器的温度高于18F。添加屏蔽导致几乎所有同位素的接触皮肤剂量率大致相等，对于每种屏蔽类型，除了89Zr明显更高。剂量率常数(μGy/MBq。hr）介绍了一系列PET同位素和屏蔽层，并讨论了它们的意义。
