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7. Recommendations for Determination of Absorbed Dose in a Phantom

This Section presents recommendations for the determination of absorbed dose in a phantom exposed to a clinical proton beam. These will include the choice of dosimetric instruments, the methods of use of these instruments and the choice of values to be used for physical parameters needed to determine absorbed dose at a point in a phantom. These recommendations are particularly important since there are currently no internationally accepted standards for the dosimetry of proton beams. The need for international uniformity of dose specification between institutions continues to grow with the number of clinical proton facilities. Existing regional standards (AAPM, 1983; Vynckier et al., 1991; Vynckier et al., 1994) cannot provide that uniformity.