Bone sarcoma to man from ²²⁴Ra, ²²⁶Ra, and ²³⁹Pu

Abstract

The induction of bone sarcomas increases with both dose and protraction of ²²⁴Ra irradiation. From ²²⁴Ra data in man, we estimate that the risk coefficient ranges from about 40 up to 200 bone sarcomas/10⁶ person·rad of average skeletal dose, depending on whether the ²²⁴Ra is given in a single injection or given weekly for several years. Limited experimental results in beagles and mice suggest that the risk per rad should be roughly similar for protracted skeletal irradiation from ²³⁹Pu and ²²⁴Ra, both of which decay to a large extent on bone surfaces. The risk coefficient for Long-lived ²²⁶Ra and ²²⁸Ra, which decay mostly within bone volume, is much smaller, and is estimated by us to lie between 6 and 53 bone sarcomas/10⁶ person·rad.

Of special interest is the risk from the ²²⁴Ra therapy currently being used in Germany, of 10 weekly injections, each of 28 µCi ²²⁴Ra, which gives a cumulative average skeletal dose of 56 rad to a 70 kg adult. Present data from the ²²⁴Ra patients indicate that the resulting risk from induced bone sarcoma is between 0 and 0.5%

Supported by USERDA Contract EY-76-C-02-0119, and by EURATOM Contract 218-76-1-BIO D.