A code of practice for clinical proton dosimetry

Proton dosimetry can be performed using different types of dosimeters, such as: calorimeters, ionisation chambers, Faraday cups, ... National standard dosimetry laboratories will, however, not provide a standard for the dosimetry of proton beams. In order to achieve uniformity on an international level, the use of ionisation chambers, calibrated in terms of air-kerma in a Cobalt-60 beam should be considered. The 'Code of Practice for Clinical Proton dosimetry' (Vynckier et al, 1991) was published four years ago, but since then new data for mass stopping powers for protons have been reported (ICRU 49, 1993). Following amendments were proposed (Vynckier et al, 1994): 1. the adoption of the mass stopping powers for protons published in ICRU 49; 2. specification of the proton absorbed dose in water. Moreover, recently data were reported on the use of a water calorimeter in clinical proton beams. Comparison of the absorbed dose determined by both methods will result in a more precise knowledge of the absorbed dose in clinical proton beams