The influence of physical wedges on penumbra and in-field dose uniformity in ocular proton beams

In ocular proton therapy, physical wedges are used in order to spare a critical tissue, e.g. optic disc or macula, or more usually, to reduce the high dose volume. Approximately half of practising ocular proton therapy centres employ wedges. For example, at the Helmholtz Zentrum Berlin [1] and at The Clatterbridge Cancer Centre (CCC), wedges are used in 70% and 30% of cases respectively. The wedge is usually mounted on the beam collimator by means of a stalk arrangement. It is normal practise to position the wedge as closely as possible to the patient's eye to minimise the effects of proton scatter, but consistent with patient safety.
Source: Physica Medica: European Journal of Medical Physics - Category: Journals (General) Authors: Tags: Technical Notes Source Type: research