Characterization and evaluation of 2.5 MV electronic portal imaging for accurate localization of intra- and extracranial stereotactic radiosurgery.
Song KH, Snyder KC, Kim J, Li H, Ning W, Rusnac R, Jackson P, Gordon J, Siddiqui SM, and Chetty IJ. Characterization and evaluation of 2.5 MV electronic portal imaging for accurate localization of intra- and extracranial stereotactic radiosurgery. J Appl Clin Med Phys 2016; 17(4):268-284.
Journal of applied clinical medical physics [electronic resource] / American College of Medical Physics
2.5 MV electronic portal imaging, available on Varian TrueBeam machines, was characterized using various phantoms in this study. Its low-contrast detectability, spatial resolution, and contrast-to-noise ratio (CNR) were compared with those of conventional 6 MV and kV planar imaging. Scatter effect in large patient body was simulated by adding solid water slabs along the beam path. The 2.5 MV imaging mode was also evaluated using clinically acquired images from 24 patients for the sites of brain, head and neck, lung, and abdomen. With respect to 6 MV, the 2.5 MV achieved higher contrast and preserved sharpness on bony structures with only half of the imaging dose. The quality of 2.5 MV imaging was comparable to that of kV imaging when the lateral separation of patient was greater than 38 cm, while the kV image quality degraded rapidly as patient separation increased. Based on the results of patient images, 2.5 MV imaging was better for cranial and extracranial SRS than the 6 MV imaging.
Medical Subject Headings
Brain Neoplasms; Cone-Beam Computed Tomography; Head and Neck Neoplasms; Humans; Image Processing, Computer-Assisted; Lung Neoplasms; Male; Particle Accelerators; Phantoms, Imaging; Radiation Dosage; Radiosurgery; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated