Evaluation of an anatomical compensation filter for chest radiography

An anatomical compensation filter for improving the radiographic demonstration of the mediastinal and retrocardiac areas of a chest radiograph has been evaluated. The filter, made of a transparent, light-weight lead-plastic material was attached to the X-ray collimator housing. The device reliably improved the visibility of normally underpenetrated areas without producing detectable artefacts, provided the patient was correctly positioned. Hilar structures were also slightly better visualised. At the same time there was no statistically significant deterioration in visualisation of peripheral pulmonary vessels or parenchymal structures. Rib details and pleural calcifications were less well seen, however, a result that was to be expected because of the X-ray beam hardening.