The 42nd Lauriston S. Taylor Lecture: Radiation Dosimetry Research for Medicine and Protection-A European Journey.

The assessment of doses related to exposures to ionizing radiation is an essential part of all applications of ionizing radiation including radiation medicine, radiation protection, radiation biology, radiation epidemiology, and also industrial uses of radiation. Absorbed dose is generally considered to be the fundamental quantity of radiation dosimetry. It is a metrologically sound quantity for which even primary standards exist for some materials, and it is used routinely in practice. However, there is no unique correlation between absorbed dose and the radiation-induced biological effect considered. There are also different objectives of radiation dosimetry for different applications. In radiation protection, quantities are required to set meaningful exposure limits and to implement the principle of optimization. In radiation therapy, the dependence of clinical outcomes on temporal aspects of the irradiations must be accounted for. In radiation diagnostics, quantities are needed to enable and monitor optimization of radiation dose and image quality. In radiation protection and in therapy with high linear-energy-transfer radiations, appropriate methods and parameters are needed to account for differences in radiation quality. These limitations of the quantity absorbed dose have led to the use of a multiplicity of dose quantities and dose modification factors. Radiation dosimetry continues, therefore, to be a field of active research regarding fundamental and conceptual aspects, taking account of advances in technologies, of novel methods in radiation therapy and diagnostics, and of progress in computational dosimetry. Dosimetry of high-energy radiations such as cosmic radiation encountered at flight altitudes and during space missions as well as at high-energy accelerators has become an important issue. In Europe, collaboration and coordination of radiation research in general, and dosimetry research in particular, are playing an important role. Dedicated research programs of the European Commission have been and still are very valuable and include collaborations with institutes in Eastern Europe and non-European countries. Several current and recent research topics in radiation dosimetry are addressed based on research carried out within European research programs, at European research centers including the European Organization for Nuclear Research (known as CERN), in European particle therapy projects, and at national metrological institutes. One focus is the quantification of radiation quality in radiation protection and in high linear-energy-transfer radiation therapy with emphasis on measurements with low-pressure proportional counters. Another focus is dosimetry of high-energy radiations with respect to measurements of cosmic radiation and at CERN’s high-energy accelerators.