DETERMINING EFFECTIVE DOSE-EQUIVALENT FOR EXTERNAL PHOTON RADIATION -ASSESSING EFFECTIVE DOSE-EQUIVALENT FROM PERSONAL DOSIMETER READINGS

Since January 1994, US nuclear plants have implemented Title of 10 Par t 20 of the US Code of Federal Relations which adopted the methodology of ICRP 26 for effective dose equivalent (H-E) for internally deposit ed radionuclides. To provide general guidance for assessing H-E from e xternal photon exposures, a two-phase research programme tvas performe d. This article presents the results for the second phase - assessment of H-E using personal dosemeters. By using a Monte Carlo photon trans port code, personal dosimetry was simulated at 480 different locations on the surface of a hermaphroditic phantom. The dosemeter readings we re compared with H-E calculated for a variety of photon sources comple ted during the first phase of this study. The data suggest that the cu rrent one-badge approach is still valid in assessing H-E for routine e xposure in many radiation fields and two dosemeters may be used for si tuations in which the exposure is less uniform. Algorithms to relate d osemeter readings to H-E are discussed for uniform and non-uniform exp osures.