Room: Exhibit Hall | Forum 5
Purpose: To determine the efficacy of surface imaging for 4D gating on animal patients. Due to the recent rise in animals receiving complex radiation therapy such as IMRT or VMAT, the question as to whether or not they can be treated with 4D gating is essential.
Methods: A coyote and rabbit pelt commercially purchased were used in conjunction with a CIRS Dynamic Thorax Phantom to be used as a patient surrogate. The phantom and pelts were imaged on a GE LightSpeed couch with surface tracking using a C-RAD Sentinel system. The phantom was programmed with an amplitude of 10 mm and a cycle time of 4 seconds to simulate breathing motion. The Sentinel recorded the phantom in real time with each pelt. Gain settings were optimized based on the individual pelt color to minimize over/under saturation, which varied greatly due to the wide range of fur color. The breathing pattern of the phantom with each pelt was recorded. A sine wave was then best fit to each of the series. This allowed for the control sine wave to be normalized and offset relative to each. A chi squared test was then run to determine how close each line was to the control, to determine the camera systemâ€™s sensitivity to the fur thickness and color.
Results: The chi squared values found ranged between 0 and 5, demonstrating significant correlation with the control sine wave.
Conclusion: Surface imaging can accurately track as a 4D gating technique for animal patients.