A dose-rate calculator.

The device described has been designed to simplify the routine calculation of dose-rates at selected points around the various gynaecological radium applicators as they appear in situ on the conventional radiographs. It was soon realised that a rigorous solution to the problem did not lend itself to the preparation of an instrument that could speed up the calculation and so certain assumptions were made, resulting in an overall accuracy commensurate with the method of treatment. The first of these assumptions is that the radiographs, antero-posterior and lateral, have standard magnifications (viz. 15 and 20 per cent respectively). The second assumption is that the sources are effectively point sources.