Report and recommendations of the advisory group

A procedure is developed to improve dosimetry and uniformity in radiotherapy, by making use of mailed dose meters for the measurement of absorbed dose. The specific aim of this postal intercomparison project is to evaluate the accuracy of the clinical delivery of dose from orthovoltage X-rays of half-value layers (HLVs) greater than 0.5 mm Cu (i.e. X-rays generated at potentials between 140 and 500 kV). The criteria for the accuracy of the dosimetry are based on the knowledge of tumour control, complications to normal tissue, and the technical possibilities. For this intercomparison it is required that the accuracy of the dose determination should be better than 10% and preferably 5%. In addition, the planned thermoluminescence dosimetry (TLD) intercomparison programme should help in the assessment of the reasons for significant discrepancies in dosimetry, should they occur