This was a prospective single-centre trial to investigate the value of OSMS, and we hypothesized that using OSMS would reduce setup error in vulvar cancer treatment compared to a standard laser-based setup. A dose of 45 Gy was delivered to the clinical target volume with intensity-modulated radiation therapy (IMRT) for a total of 25 fractions, followed by 16 to 24 Gy of local electron beam supplementation. Marks were placed on each patient's skin to align the room lasers for presetup, and the setup was completed with information from the OSMS. The deviation values in three translation directions, lateral (Lat), longitudinal (Lng), and vertical (Vrt), and three rotation directions, Rtn (rotation along the z-axis), Pitch (rotation along the x-axis), and Roll (rotation along the y-axis) were obtained. The absolute values of setup error and error distribution of the standard laser-based setup and OSMS were compared.
This prospective study evaluated the clinical implementation value of an optical surface monitoring system (OSMS) in the radiotherapy setup for patients with vulvar cancer, compared to standard laser-based setup