Protocol for X-ray dosimetry in radiobiology

Purpose: To harmonize X-ray dosimetry in radiobiology to allow a direct com parison of radiobiological studies performed at institutes cooperation with in the framework of the European Late Effects Project Group (EULEP). Materials and methods: The 1985 EULEP protocol for X-ray dosimetry and expo sure arrangements employed for studies of late somatic effects in mammals r equired serious revision, e.g. due to the replacement of calibration of dos emeters in terms of exposure by calibration in terms of air kerma free-in-a ir. An action group established by EULEP and the European Radiation Dosimet ry Group (EURADOS) updated the 1985 protocol. Results: The new EULEP EURADOS protocol for X-ray dosimetry in radiobiology including the code of practice for irradiation of small animals and relate d dosimetry. The present protocol includes the changes in calibration proce dures and dosimetric concepts for irradiation with medium energy X-rays sin ce 1985. Accuracy and precision are replaced by the concept of combined (st andard) uncertainty. The revised supplements provide more detailed backgrou nd information. New appendices contain definitions of general terms used fo r measurements and mathematical expressions of the relative variances. Conclusion: Adherence to the present protocol will result in improved dosim etry and facilitates the comparison of results of radiobiological experimen ts obtained at different institutes.