International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · May 2018
Determination of Intrafraction Prostate Motion During External Beam Radiation Therapy With a Transperineal 4-Dimensional Ultrasound Real-Time Tracking System.
To determine intrafraction prostate motion during volumetric modulated arc therapy (VMAT) using transperineal ultrasound (US) real-time tracking. ⋯ The magnitudes of intrafraction prostate motion along the SI and AP directions were comparable. On average, the smallest motion was in the LR direction and the largest in AP direction. Most of the prostate displacements were within a few millimeters. However, with increasing treatment time (eg, during hypofractionation), larger 3-dimensional prostate displacements up to 18.30 mm could be observed. Shortening treatment time can reduce the impact of intrafraction motion and potentially allows smaller safety margins.