Salmon P L, Henshaw D L, Bondarenko O A, Thomas P A, MacDonald C R, Goodall C
H. H. Wills Physics laboratory, Bristol University, UK.
Int J Radiat Biol. 1995 Dec;68(6):655-61. doi: 10.1080/09553009514551661.
Alpha particle energy spectra were measured at femoral endosteal surfaces of Canadian Arctic caribou (Rangifer tarandus) to assess the profile of concentration with depth of 210Po supported by 210Pb. Femur samples from five caribou all showed a pronounced superficial concentration of 210Po, in a layer 1.9 - 6.4 microns thick. Within this layer 210Po was concentrated 1.5 - 10 times with respect to diffuse volume-distributed 210Po. This result is consistent with an earlier study of 210Po at human cranial bone surfaces, which showed 210Po to be concentrated about four times in a surface layer <3 microns thick. However, the present results have higher precision than the human bone data due to the much greater concentration of 210Pb and 210Po in caribou bone. The validity of using 210Po as a marker of 210Pb, and the in vivo 210Po/210Pb ratio are discussed. As a result of the measured endosteal superficial concentration of 210Po in caribou, the alpha particle dose was calculated to be enhanced by a factor of 1.06 - 1.96 (mean 1.48) for bone lining cells, and of 1.08 - 2.39 (mean 1.69) for soft tissue above the bone surface, assuming equilibrium between 210Pb and 210Po. It is suggested that an additional longer-lived compartment for bone surface lead could be incorporated into bio-kinetic models for lead.
在加拿大北极驯鹿（Rangifer tarandus）的股骨骨内膜表面测量了α粒子能谱，以评估由²¹⁰Pb支持的²¹⁰Po随深度的浓度分布情况。来自五只驯鹿的股骨样本均显示，在厚度为1.9 - 6.4微米的一层中，²¹⁰Po有明显的表面富集。在这一层中，²¹⁰Po的富集程度相对于扩散分布的²¹⁰Po为1.5 - 10倍。这一结果与之前对人类颅骨表面²¹⁰Po的研究一致，该研究表明，²¹⁰Po在厚度小于3微米的表面层中富集约四倍。然而，由于驯鹿骨骼中²¹⁰Pb和²¹⁰Po的浓度要高得多，目前的结果比人类骨骼数据具有更高的精度。讨论了使用²¹⁰Po作为²¹⁰Pb标记物的有效性以及体内²¹⁰Po/²¹⁰Pb比值。由于测量到驯鹿骨内膜表面²¹⁰Po的富集，假设²¹⁰Pb和²¹⁰Po处于平衡状态，计算得出骨衬细胞的α粒子剂量增强了1.06 - 1.96倍（平均1.48倍），骨表面上方软组织的α粒子剂量增强了1.08 - 2.39倍（平均1.69倍）。建议可以将一个额外的、寿命更长的骨表面铅隔室纳入铅的生物动力学模型中。
