Article
Cyberknife frameless real-time image guided stereotactic radiosurgery for the treatment of spinal lesions
Cyberknife rahmenlose Echtzeit geführte stereotaktische Radiochirurgie für die Behandlung von spinalen Läsionen
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Published: | May 8, 2006 |
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Objective: The role of cranial radiosurgery is well established. Its use for the treatment of spinal lesions has been limited by the availability of effective target-immobilizing devices. The Cyberknife (Accuray, Sunnyvale, CA, USA) is an image guided frameless stereotactic radiosurgery system that allows for the radiosurgical treatment of spinal lesions. This study evaluated the feasibility and effectiveness of the treatment of spinal lesions with a single fraction radiosurgical technique.
Methods: The Cyberknife system uses the coupling of an orthogonal pair of X-ray cameras to a dynamically manipulated robot-mounted linear accelerator wit six degrees of freedom that guides the therapy beam to the intended target without the use of frame-base fixation. Real time imaging allows the tracking of patient movements. Lesions were tracked by bony landmarks without any implanted fiducials. In this prospective cohort evaluation of spine radiosurgery technique, 18 spinal lesions in 13 consecutive patients were treated with single fraction radiosurgery technique (5 cervical, 6 thoracic, 6 lumbar, 1 sacral). There were 3 nerve sheath tumours and 10 metastatic lesions. All dose plans were calculated on the basis of computed tomographic images acquired from 1.5-mm slices with an inverse treatment planning technique.
Results: All patients tolerated the radiosurgical procedure well. Tumour volume ranged from 1.6 to 17 ccm. 8 patients had received conventional external beam irradiation before radiosurgery. Spinal tracking was also possible after transpedicular screw fixation. Tumour dose was maintained at 13.5 to 18 Gy to the 70% isodose line. No acute radiation toxicity or new neurological deficits occurred during the follow-up period (range: 1-5 months). Axial and radicular pain improved in all patients who were symptomatic before treatment.
Conclusions: Spinal Cyberknife radiosurgery is a new safe and effective outpatient treatment method for spinal tumours. This technique offers a successful therapeutic modality as a primary treatment, for lesions not amenable to open surgical techniques, in medically inoperable patients, in lesions located in previously irradiated sites, or as an adjunct to multidisciplinary treatment concepts.