Dosimetry Intercomparisons for Evaluation of Late Effects of Ionizing Radiation

Evaluation of the late somatic effects of ionizing radiation in mammalian organisms is of great importance for assessment of the risks of low level radiation exposure.Since this type of research requires large scale experiments and long term commitments of personnel and facilities, a joint project was initiated by a group of institutes cooperating within the European Late Effects Project Group (EULEP).A prerequisite for coordination of research programs is the standardization of experimental methods and materials such as exposure arrangements and dosimetry, pathology and the quality of experimental animals.Investigations in radiation biology and radiation therapy have demonstrated that differences of 10 per cent in absorbed dose will produce clearly observable variations in biologic response.In general, cell survival analyses do not allow the prediction of variations in absorbed dose determinations smaller than 5 per cent.It has been suggested therefore that an accuracy of 5 to 6 per cent and a precision of 2 to 3 per cent is required for the determination of absorbed dose in biologic applications (BROERSE & MIJNHEER 1976).It must be recognized that these requirements are more severe than generally encountered in radiation protection.Taking into account the estimated precision and uncertainty of the TLD system (1.2 per cent and 3 per cent, respectively), the following recommendations were formulated (cf.BROERSE & PU~TE 1974)