Abstract

Background
：This study was performed to test feasibility of CBCT(cone-beam computerized tomography) guided radiosurgery. Materials and Methods：We used CBCT which was mounted on a retractable arm at 90° to the treatment source. CBCT images were overlapped on the digitally reconstructed images from simulation CT scan. Then, 3 dimensional volumetric CT image matching was performed. If there were any positioning errors, automated patient re-positioning was done.
Results
：A radiosurgery treatment plan was carried out with a set of specially designed multiple non-coplanar arcs. The goal of plan was to deliver single session 18 Gy at periphery of the target. We treated a patient with a solitary brain metastasis from left upper lung cancer. Serial imaging study for treatment response revealed a satisfactory result with no remarkable treatment related side effects.
Conclusion
：CBCT image guided radiosurgery system is very simple and could be a convenient image guiding modality for stereotactic radiosurgery or fractionated radiotherapy with an acceptable geometric accuracy and radiation exposure.

• Keywords: Cone-beam computerized tomography, Stereotactic radiosurgery, Brain metastasis;