The first experimental study was performed to quantify the inaccuracy in clinical dose delivery due to the incomplete scatter conditions inherent in IOHDR brachytherapy. Treatment plans were developed for 3 different treatment surface areas (4 x 4, 7 x 7, 12 x 12 cm2), each with prescription points located at 3 distances (0.5 cm, 1.0 cm, and 1.5 cm) from the source dwell positions. Measurements showed that the magnitude of the underdosage varies from about 8% to 13% of the prescription dose as the prescription depth is increased from 0.5 cm to 1.5 cm. This treatment error was found to be independent of the irradiated area and strongly dependent on the prescription distance. The study was extended to confirm the underdosage for various shape of treated area (especially, irregular shape), which can be applied in clinical cases. Treatment plans of 10 patients previously treated at Roswell Park Cancer Institute in Buffalo, which had irregular shapes of treated areas, were used.Whichever unit is used, it is also required to enter a conversion factor k, specified on the Certificate for Sealed Sources. This is currently fixed at 0.466 . The Reference Air Kerma Rate is calculated by multiplying the Exposure Rate given on theanbsp;...
|Title||:||Systematic Analysis of the Scatter Environment in Clinical Intra-operative High Dose Rate (IOHDR) Brachytherapy|
|Publisher||:||ProQuest - 2008|