Protocol for X-ray dosimetry in radiobiology

Purpose : To harmonize X-ray dosimetry in radiobiology to allow a direct comparison of radiobiological studies performed at institutes cooperating within the framework of the European Late Effects Project Group (EULEP). Materials and methods : The 1985 EULEP protocol for X-ray dosimetry and exposure arrangements employed for studies of late somatic effects in mammals required serious revision, e.g. due to the replacement of calibration of dosemeters in terms of exposure by calibration in terms of air kerma free-in-air. An action group established by EULEP and the European Radiation Dosimetry 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 related dosimetry. The present protocol includes the changes in calibration procedures and dosimetric concepts for irradiation with medium energy X-rays since 1985. Accuracy and precision are replaced by the concept of combined (standard) uncertainty. The revised supplements provide more detailed background information. New appendices contain definitions of general terms used for measurements and mathematical expressions of the relative variances. Conclusion : Adherence to the present protocol will result in improved dosimetry and facilitates the comparison of results of radiobiological experiments obtained at different institutes.