A nine-degree-of-freedom optimization-based method to evaluate the isocenter coincidence of the treatment beams and image system of a medical accelerator

• DOI: 10.3389/fphy.2024.1395997
• Publication Date: 2024-06-11T19:27:19Z
• Authors: Yun Zhou; Jian Qiao; Nan Yan; Liyan Dai; Yuehu Pu
• Keywords: Isocenter; Image-guided radiation therapy; Truebeam

Medical accelerators have been widely used in tumor radiation therapy. Accurate isocenter coincidence between treatment beams and imaging systems is critical for image-guided therapy (IGRT). We propose a method utilizing phantom with marker spheres to detect the Nine Degrees of Freedom (9-DOF) system’s geometric model assess kV cone-beam computed tomography (CBCT). The was initially aligned accelerator. Subsequently, projections CBCT beams’ were acquired separately full gantry rotation. By analyzing spheres’ position both beam projections, 9-DOF parameters calculated. A comparison Winston-Lutz-based system performed. Then, analysis revealed imprecise circular trajectories noticeable random deviations rotations CBCT. 0.18 mm (X), −0.49 (Y), −0.35 (Z) after fitting, respectively. rotational planes two exhibited pinch angle 0.0235°. This proposed offers quantitative assessment pose source detector panel, an accelerator at each angle.