Organ Doses and Effective Dose Equivalent for External Neutron Beams Derived by the CHORD-Method

摘要

The CHORD-method was applied to the anthropomorphic MIRD-V-phantom, to derive average organ doses for external neutron beams. The phantom was modified by adding suitable breasts, and introducing ovaries. The influence of a more realistic neck on the thyroid doses in comparison with the MIRD-bull-neck was assessed. The depth doses used were those for the total absorbed dose and dose equivalent, including the internally produced gammas, as well as for the neutron component only. The data were taken from ICRP 21 and fitted in the depth interval from zero to 26 cm by suitable analytical expressions. This allowed extrapolation beyond 30 cm phantom depths, as necessary in case of bone density corrections of relevant track length distributions for rays intersecting bone regions. All doses were normalized to the incoming unit neutron fluence, the absorbed doses also to soft tissue KERMA free in air. Based upon the organ dose equivalents, the effective dose equivalent, following ICRP 26, was derived. (ERA citation 09:034397)