The Protection of Radium Workers from Gamma Radiation

Abstract

Arising in part from the working association of the National Physical Laboratory with the National Radium Commission, the two main factors of gamma-ray protection, viz., remoteness and lead shielding, have been experimentally studied during the last few years in a variety of routine circumstances, e.g., the storage, manipulation and transport of radium, as well as its employment in lead “bombs” for beam therapy. The minimum shielding and the tolerance working distance have been determined under various conditions on the assumptions of a daily tolerance dose of 0·2 röntgen and a Sievert gamma-ray unit “dose” of 8 röntgens. The results are also calculable in simple cases from the lead transmission curve of gamma rays, which has also been determined under conditions taking full account of scattering. The conclusions of the paper, which, in general, fully support the recommendations of the International and British Protection Committees, establish inter alia the undesirability of staff remaining in the immediate vicinity of patients undergoing treatment with large quantities of radium, the high degree of protection attainable with properly designed radium safes, the importance of expeditious manipulation of radium containers, the advisability of employing temporary workers in busy radium centres, and the superiority from the point of view of radium protection of bulky postal transport boxes with only moderate lead shielding over small containers utilising the maximum lead shielding possible under the parcel-post regulations.