Abstract
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Objectives To calculate beta-ray dose kernels for point sources of Ho-166 and Lu-177 in water.
Methods W.G. Cross, et al., published (AECL-10521, 1992) a dimensionless dose distribution table for mono-energetic beta particles and combined those with beta-ray energy spectra to calculate dose kernels. Ho-166 and Lu-177 are radionuclides of recent clinical interest that are were not included. Software was written in the Java programming language implementing Cross' approach. It imports ICRP 38 beta energy spectra from the DEXRAX32 program and interpolates them. The quantity r2J(r,E) (Cross' equation 5) is computed for various distances from the point source by interpolating and integrating Cross' dimensionless dose distribution, weighted by the actual beta spectrum using beta ranges in water given by the ESTAR CSDA data.
Results Dose kernels for several radionuclides tabulated by Cross agree well with Cross' results except at r=0 and at the end of the beta range where the differences are as much as 60%. Cross, et al., noted problems near r=0. Their values close to the maximum beta range have reduced precision and higher intrinsic error.
Conclusions Dose kernels for Ho-166 and Lu-177 have been calculated by a reliable implementation of Cross' computation