Six Degree-of-Freedom Image Guidance for Frameless Intracranial Stereotactic RadioSurgery with kilo-voltage Cone- Beam CTZheng Chang1*, Zhiheng Wang1, Jinli Ma1,2, Q. Jackie Wu1, Ryan McMahon1, John P. Kirkpatrick1 and Fang-Fang Yin1
- Corresponding Author:
- Zheng Chang, Ph.D.,
Department of Radiation Oncology
Duke University Medical Center, Durham, NC 27710, USA
Tel: (919) 681-2608
Fax: (919) 681-7183
E-mail: [email protected]
Received Date: November 22, 2010; Accepted Date: December 23, 2010; Published Date: December 26, 2010
Citation: Chang Z, Wang Z, Ma J, Wu QJ, McMahon R, et al. (2010) Six Degree-of- Freedom Image Guidance for Frameless Intra-cranial Stereotactic RadioSurgery with kilo-voltage Cone-Beam CT. J Nucl Med Radiat Ther 1:101. doi:10.4172/2155-9619.1000101
Copyright: © 2010 Chang Z, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract Purpose: To investigate localization accuracy for frameless intracranial stereotactic-radiosurgery using 2D orthogonal planar imaging and 3D cone-beam CT (CBCT) in 6-degree-of-freedom (6-DOF).
Methods and Materials: In a phantom study, a target ball phantom was used to perform a Winston-Lutz test and to verify coincidence of imaging isocenter and radiation isocenter. A head phantom was placed with pre-defined positions and imaged with CBCT to test imaging accuracy. In a patient study, one hundred patients were included. Patients were initially positioned with a thermoplastic frameless mask system and then aligned with orthogonal planar imaging and CBCT. The setup discrepancies were quantitatively analyzed.
Results: Phantom experiments showed discrepancies in root-mean-square were 1.6mm translationally and 0.5° rotationally between CBCT 6-DOF image guidance and the known displacements after deviations from the radiation isocenter are considered. In the patient study, setup displacements between orthogonal planar imaging and CBCT 6-DOF image guidance were 3.2mm translationally and 0.9° rotationally. The positioning of twelve patients was corrected in 6-DOF using CBCT and a robotic couch to reduce translational and rotational discrepancies of 1.4mm and 1.3°, as compared with standard CBCT translational correction. Conclusion: CBCT 6-DOF image guidance offers an explicit view to verify patient positioning in translations and rotations.