A photographic film method for the evaluation of the filtration of half value thickness of X-ray tube

An easy and a reliable method using personnel monitoring films has been described here for determining the total filter incorporated in a diagnostic X-ray unit. The same method is applicable for determining the half value thickness of beams from therapy machines. Some of the typical calibration graphs obtained have been presented. The method has been tested in a large number of cases during protection surveys and has been observed to be specially useful in the case of radiography tubes. (author)