Respiratory guiding system for respiratory motion management in respiratory gated radiotherapy

Respiratory guiding systems have been shown to improve the respiratory regularity. This, in turn, improves the efficiency of synchronized moving aperture radiation therapy, and it reduces the artifacts caused by irregular breathing in imaging techniques such as four-dimensional computed tomography (4D CT), which is used for treatment planning in RGRT. We have previously developed a respiratory guiding system that incorporates an individual-specific guiding waveform, which is easy to follow for each volunteer, to improve the respiratory regularity. The present study evaluates the application of this system to improve the respiratory regularity for respiratory-gated radiation therapy (RGRT). In this study, we evaluated the effectiveness of an in-house-developed respiratory guiding system incorporating an individual specific guiding waveform to improve the respiratory regularity for RGRT. Most volunteers showed significantly less residual motion at each phase during guided breathing owing to the improvement in respiratory regularity. Therefore, the respiratory guiding system can clearly reduce the residual, or respiratory, motion in each phase. From the result, the CTV and the PTV margins during RGRT can be reduced by using the respiratory guiding system, which reduces the residual motions, thus improving the accuracy of RGRT