A SYSTEM POR THE CALCULATION OP DOSE PRODUCED BY EXTERNAL PHOTON BEAMS

Abstract

External photon beam therapy is a well established technique in the treatment of cancer. For the safe and effective use of this technique it is essential that the distribution of dose which would be produced by a given photon beam, or combination of photon beams, be known prior to irradiation. This thesis outlines a computer tomography (CT) number based system for calculating such dose distributions using the equivalent tissue-air ratio method. The system is composed of a number of programs which extract patient anatomical data from GE 8800 CT scanner archival tapes, calculate the dose distribution which would result from a given external beam, and display the calculated dose distribution using coloured digital images.