Lloyd R D, Jones C W, Bruenger F W, Atherton D R, Mays C W
Radiat Res. 1983 May;94(2):295-304.
Retention of administered 226Ra was substantially greater in beagles injected as 3-month-old juveniles than as 1.4-year-old young adults, but the measured 222Rn/226Ra ratio in bone was significantly less in juveniles for about the first 600 days after injection. An equation that describes the total-body biological retention R in beagles injected with 226Ra at 3 months of age at any time t (in days) after injection during the first 6.6 years is R = 0.331e-0.206t + 0.245e-0.00374t + 0.424e-0.000114t. The rate constant of the final term in the equation for juveniles is similar to that for young adults, suggesting that this component reflects the net turnover rate in the slowly remodeling component of adult bone. Compared to young adult beagles, animals injected as juveniles had a greater fraction of their retained 226Ra in parts of the skeleton containing much cortical bone, such as paws, and a smaller fraction in those parts containing much trabecular bone.
与1.4岁的青年犬相比，3个月大的幼年比格犬对注入的226Ra的保留量要大得多，但在注射后的大约前600天内，幼年犬骨骼中测得的222Rn/226Ra比值明显较低。一个描述在6.6年的首个时间段内，3个月大时注入226Ra的比格犬在注射后任何时间t（以天为单位）全身生物保留量R的方程为：R = 0.331e-0.206t + 0.245e-0.00374t + 0.424e-0.000114t。该方程中幼年犬最后一项的速率常数与青年犬相似，这表明该成分反映了成年骨骼缓慢重塑成分中的净周转率。与青年比格犬相比，幼年时注射的动物在含有大量皮质骨的骨骼部位（如爪子）中，其保留的226Ra所占比例更大，而在含有大量小梁骨的部位所占比例更小。
