Presentation of TRS no. 277 ''Absorbed dose determination in photon and electron beams''. An international code of practice

The IAEA/WHO Network of SSDLs was set up in order to ''improve accuracy in applied radiation dosimetry throughout the world''. The first step in this procedure has been to establish a number of SSDLs. The next step involves the transfer of calibrations to hospitals, laboratories, etc. from the SSDLs. Transfer of calibrations from SSDLs to the users includes many problems, for instance, the radiation quality may be quite different at the beams used by the SSDLs and by the hospitals and the radiation quantity may be different for the calibration and application. TRS No. 277 deals with the procedure to be used. During the past few years, several national organizations have prepared codes of practice, protocols and documents (see e.g. ESTRO 1985), which give recommendations for absorbed dose determination for high energy electron and photon beams based on the use of ionization chambers calibrated in exposure or air kerma. In general, the recommendations are somewhat too specific in that they serve for the conditions in the countries in which the documents originated. An advisory group met therefore in Vienna in 1985 to outline an international code of practice. This group consisted of nine members, who all had been involved in similar work on a national scale. From this group, four principle authors were chosen: P. Andreo (Spain, now Sweden), J.R. Cunningham (Canada), K. Hohlfeld (Federal Republic of Germany) and H. Svensson (Sweden, now IAEA). Before its publication, the manuscript was circulated for comments to the advisory group and also to a number of other persons with special interest in the field. The final test of the Code will take place when it is applied in SSDLs and hospitals. Several comments have now been submitted to the IAEA Dosimetry Section. A co-ordinated research programme carried out to test the Code has just started. Both SSDLs and hospitals are participating. The test will probably result in a revision of the Code. The general philosophy behind the Code as well as some comments received till now are provided