Monte Carlo dose calculations for a new avoid shield system for carcinoma of the uterine cervix

The dose distribution for an ovoid with a new tungsten shielding design was determined using Monte Carlo simulation. Standard Cesium-137 tube sources, tungsten shielding, and aluminum ovoid applicator were each modeled as a c ollection of solid objects. Dose was calculated in planes above, below, in front of, and on the sides of the colpostat. The Monte Carlo results were c ompared with the results from a parametrized calculation algorithm and good agreement was obtained. The dose distribution matrix derived from the para metrized algorithm can be used for clinical treatment planning. (C) 1998 Am erican Association of Physicists in Medicine. [S0094-2405(98)01412-6].