The need for repeated intercomparisons and standardization of X-ray dosimetry for the co-ordination of late-effects research in Europe

In 1971, 1973 and 1976, intercomparisons of absorbed dose and dose distribution over a mouse phantom for X-rays were performed as part of the programme of the European Late-Effects Project Group (EULEP). Sixteen institutes from eight countries participated in the sessions of the third intercomparison. In general, progress has been made with regard to accuracy and precision of the X-ray dosimetry; in two cases, discrepancies could be resolved after additional measurements. With regard to the dose distribution over a mouse phantom, the results are not satisfactory; four out of fifteen participants are still unable to perform uniform irradiations. It is clearly shown that it is necessary to undertake repeated intercomparisons to allow meaningful comparisons of biological results obtained in a co-operative research programme to be made. (author)