SU‐E‐J‐89: GammaPlan MR to CT Image Registration Errors: Implications for Extend and Preplanned Treatments

• Published in: Medical Physics 2013-06, Vol.40 (6), p.170-170
• Main Authors: Sudhyadhom, A, Perez‐Andujar, A, Ma, L, Barani, I
• Format: Article
• Language: English
• Subjects: Anatomy; Computed tomography; Image registration; Radiosurgery
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.4814301

Purpose: To compare the spatial errors in coordinate localization created by MR‐based stereotaxia in GammaPlan for two different Methods: direct stereotactic MR localization and MR co‐registration with a stereotactic CT. Methods: Seven patients underwent Gamma Knife SRS and were scanned with our clinical stereotactic MR and stereotactic CT protocols. In GammaPlan, the stereotactic coordinate system for each MR and CT was defined using the fiducials of the localizer. Separately, each MR was co‐registered (by the patient's anatomy) to the stereotactic CT using GammaPlan's automated co‐registration algorithm. A rigid transformation relationship was determined between the direct stereotactic MR (stereoMR) and the MR co‐registered to the stereotactic CT (coregMR). Spatial errors in coordinate definition between these two methods were calculated at the center of stereotactic space and at the centroid of the target. A total of seventeen MR scans were analyzed by this method including both axial and coronal acquisitions. Results: Mean errors in fiducial definition were found to be 0.6±0.3mm and 0.7±0.3mm for CT and MR, respectively. At the center of stereotactic space, the mean magnitude error in coordinate localization between stereoMR and coregMR was found to be 1.6±0.6mm. At the centroid of the target, the mean magnitude error was found to be 1.5±0.7mm. These results were statistically significant compared to the errors in fiducial definition (p