The Measurement of the Dosage and Intensity Distribution in the Radium Teletherapy Unit at Westminster Hospital

The results are given of a series of water phantom measurements, by Sievert's condenser chamber method, on the intensity distributions of the 2 gm. radium bomb in use at the Westminster Hospital Annexe, London. The best thickness of secondary copper filter is discussed and results are given that show “back-scatter” at the surface to be negligible for this particular unit. The results for the measurement of doses for various radium-skin distances are expressed graphically. The expression of therapeutic doses in r units is discussed, and the skin erythema dose in r, thus found, is compared with values given by other workers.