The Radium Standard for Boneseekers-evaluation of the Data on Radium Patients and Dial Painters

Publisher Website
Google Scholar
Abstract
The selection in 1941 of 0.1 [mu]g radium as the maximum permissible skeletal burden was based on the then-studied total of about 30 cases. Approximately 420 radium cases (about 2/3 of whom were dial painters) were studied at MIT [Massachusetts Institute of Technology], and about 275 additional cases at Argonne National Laboratory. Approximately 100 of the MIT cases ingested mixtures of Ra226 and Ra228 (MsTh [mesothorium]. The MsTh radiation dose is expressed in terms of the amount of pure Ra226 which would produce the same skeletal dose measured in cumulative rads. The total effect of the mixtures is expressed as "pure radium equivalent", or [mu]g Ra (PRE). No clinically significant signs or symptoms were seen in persons with residual body burdens of less than 0.5 [mu]g Ra (PRE). Above 0.5 ng the incidence and severity of symptoms increases with increasing residual body burden. The usual clinical sign of osteoporosis is followed by symptoms which include primarily osteomyelitis, spontaneous fracture, osteogenic sarcomas, and carcinomas of the paranasal sinuses or roast oids, all referable to [alpha]-ray bombardment of bone or immediately adjoining tissue. Out of 81 cases 0.5 [mu]g Ra (PRE) or higher (up to 44 [mu]g) the MIT series contains 26 cases with osteogenic sarcoma and 7 cases with paranasal or mastoid carcinoma. Within any dose bandwidth, e.g. 2-5 [mu]g Ra (PRE) or 10-15 [mu]g Ra (PRE) the incidence (fraction of cases with sarcoma or carcinoma) is roughly 40%. The time of onset for sarcomas is 7-43 yr (median 23 yr) after first exposure; for carcinomas it is 19-41 (median 34 yr) after first exposure. The MIT and the Argonne groups jointly developed a semlquantitative method for assigning a numerical "X-ray score" (running from 0 to 45 in the cases studied) as a single parameter describing the effects produced by skeletal irradiation. All the radium burdens reported are the residual body burdens, usually 30-50 yr after radium was taken into the body. The initial or maximum skeletal radium burden was much larger, typically about 20 times the residual burden. The present Radiation Protection Guide or standard of a maximum skeletal disposition of 0.1 ng Ra (PRE) appears abundantly safe and conservative.

This publication has 2 references indexed in Scilit: