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Computer generated scatter dose distributions for 6‐MV radiotherapy photon beams
Author(s) -
Bloch Peter,
Wallace Robert
Publication year - 1979
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.594527
Subject(s) - percentage depth dose curve , dosimetry , grid , radiation , photon , physics , beam (structure) , optics , computational physics , mathematics , nuclear medicine , ionization chamber , ionization , geometry , medicine , ion , quantum mechanics
The time required for accurate computer dose distributions is of major concern in radiation therapy. Isodose distributions were obtained by calculating the primary and scatter radiation reaching a point. A description of the primary dose distribution, especially at the edge of the beam, requires the calculation of the dose on a finely spaced grid. However, the scatter dose distributions can be described on a much coarser grid. The primary and scatter dose distribution calculations were separated into two computer subroutines which permitted choosing the appropriate grid spacing for each dose component. A more rational partition of the computing time for the primary and scatter dose was obtained. In addition, the separation of the calculation of the scatter dose from the total dose allows one to examine the calculated scatter dose distribution as the radial and angular increments used in the Clarkson–Cunningham summation are varied. Accurate scatter dose distributions were generated with a tenfold time reduction by optimization of grid spacing and radial and angular increments.