Room: AAPM ePoster Library
Stable, deep inspiration breath-holds (DIBH) are crucial for reducing heart dose during left-sided breast irradiation. The purpose of this study is to compare the performance between the active breathing coordinator (ABC) and VisionRT technologies for producing consistent, deep inspiration breath-holds during treatment.
A series of eight patients, all with left-sided breast cancer, were enrolled in an IRB approved protocol where DIBH was performed for treatment. The first 14 fractions of the 28 fraction treatment employed either ABC or VisionRT and the last 14 employed the other. The orders of the techniques were randomized. During treatment, intra-fraction motion was determined primarily by utilizing MV cine imaging capabilities. The MV imaging series were exported and were analyzed by determining the variation in the skin-air interface of the breast for each image. The overall stability of each method, therefore, was determined by assessing the standard deviation of the skin motion during treatment. In addition, the overall fractional treatment times were also compared.
Overall, VisionRT produced lower standard deviations (±5.64mm) than ABC (±7.56mm) when analyzing all of the patient images. Also, VisionRT produced smaller surface deviations for the majority (75%) of patients, but these results were not statistically lower (p=0.105). Finally, the overall treatment times showed no appreciable difference as both methods had an average delivery time of 21.5 minutes.
Although not statistically significant, VisionRT appears to be superior in the overall surface stability of DIBH. Future work will focus on analyzing the chest wall and lung motion of these patients, as well as determining the differences in heart dosimetry between these two methods.