USE OF THE FAST HARTLEY TRANSFORM FOR 3-DIMENSIONAL DOSE CALCULATION IN RADIONUCLIDE THERAPY

Effective radioimnnunotherapy may depend on a priori knowledge of the radiation absorbed dose distribution obtained by trace imaging activit ies administered to a patient before treatment, A new, fast, and effec tive treatment planning approach is developed to deal with a heterogen eous activity distribution. Calculation of the three-dimensional absor bed dose distribution requires convolution of a cumulated activity dis tribution matrix with a point-source kernel; both are represented by l arge matrices (64 x 64 x 64). To reduce the computation time required for these calculations, an implementation of convolution using three-d imensional (3-D) fast Hartley transform (FHT) is realized. Using the 3 -D FHT convolution, absorbed dose calculation rime was reduced over 10 00 times. With this system, fast and accurate absorbed dose calculatio ns are possible in radioimmunotherapy. This approach was validated in simple geometries and then was used to calculate the absorbed dose dis tribution for a patient's tumor and a bone marrow sample. (C) 1998 Ame rican Association of Physicists in Medicine, [S0094-2405(98)03310-0].