Bergeron Denis E, Fitzgerald Ryan
Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Appl Radiat Isot. 2015 Aug;102:74-80. doi: 10.1016/j.apradiso.2015.05.003. Epub 2015 May 9.
Ra-223 is an alpha-emitter that is being used as a bone-seeking radiotherapeutic agent. The relatively large uncertainty on its evaluated half-life (0.26%, Bé et al., 2011) is an impediment to precision activity assays, which often involve measurements by various methods over time spans of days or weeks. We have performed two series of measurements using an ionization chamber (IC) and a NaI(Tl) well counter (γ-wc) to determine new, precise values for the (223)Ra half-life. We have endeavored to realistically assess the uncertainties on the derived half-lives, looking beyond the fit uncertainties to identify uncertainty components acting on multiple timescales. We recovered respective values of 11.447(6)d and 11.445(13)d from the IC and γ-wc measurements. Our values are in accord with the evaluated value of 11.43(3)d, but with smaller combined uncertainties.
镭-223是一种发射α粒子的物质，正被用作一种亲骨性放射治疗剂。其评估半衰期存在相对较大的不确定性（0.26%，贝等人，2011年），这对精确的活度测定是一个障碍，精确的活度测定通常涉及在数天或数周的时间跨度内通过各种方法进行测量。我们使用电离室（IC）和碘化钠（铊）井型计数器（γ-wc）进行了两组测量，以确定镭-223半衰期的新的精确值。我们努力切实评估导出半衰期的不确定性，不仅仅关注拟合不确定性，还识别在多个时间尺度上起作用的不确定性分量。我们从电离室和γ-wc测量中分别得到了11.447(6)天和11.445(13)天的值。我们的值与评估值11.43(3)天一致，但组合不确定性更小。
