A new treatment time calculator designed to avoid errors in 60Co therapy.

Abstract

Regular checking of radiotherapy treatment sheets has shown that the largest single cause of mistakes is misreading of tabulated data of all kinds. It is therefore important to examine the whole problem of data presentation periodically in order to find and eliminate those steps at which errors are most frequent, and to devise new methods which anticipate the problem by reducing the use of tabulated figures to a minimum. This paper describes one successful method that was introduced for this purpose about eight years ago in this centre, by presenting the complete output data of one cobalt teletherapy unit in a form that practically eliminates reading errors and at the same time contains three additional important features: (1) direct indication of treatment time for any field size and given dose, thereby avoiding the need for slide rule calculations, which are another error-prone step in the data chain; (2) source decay over a six-year period is dealt with by a simple adjustment carried out once each mont...