~(226)Ra 是一种极毒的亲骨性元素,它的物理半衰期长达59×10~5天,在骨中的生物半排出期为1.64×10~4天~([1])。~(226)Ra 被人体摄入长期沉积于骨骼中,若达到一定的积累量,就会对人体有影响,甚至引起严重的恶性肿瘤~([1]),摄入1微居里 Ra 每100万人中每年产生骨肿瘤22～33例~([2])。电离辐射不仅能诱发癌症而且也具有因并发其他疾病而增加死亡率和缩短寿命的效应~([2])。为了制订放射卫生标准,就必须首先了解环境和人体现有的放射性本底水平。而有关人体放射性 Ra 含量水平,自50年代以来,国外有不少资料~([3]),但国内目 ~ (226) Ra is a very toxic bone-like element with a physical half-life of 59 × 10 ~ 5 days and a biological half-life in bone of 1.64 × 10 ~ 4 days ([1]). . ~ (226) Ra is ingested by the human body and is deposited in the bones for a long period of time. If it reaches a certain amount of accumulation, it will affect the human body and even cause serious malignancy ~ [[1]), intake of 1 microcurie of Ra per Of the 1 million people, 22 to 33 cases of bone tumors occur each year ([2]). Ionizing radiation not only induces cancer but also has the effect of increasing mortality and shortening longevity due to concurrent other diseases ([2]). In order to formulate radiological health standards, it is necessary to first understand the environment and the human body’s existing radioactive background level. Regarding the level of radioactive Ra in the human body, since the 1950s, there have been a lot of data abroad ([3]), but domestic