Radiosurgery In Patients Research Articles

Linac-based stereotactic radiotherapy and radiosurgery in patients with meningioma

BackgroundIt was our purpose to analyze long-term clinical outcome and to identify prognostic factors after Linac-based fractionated stereotactic radiotherapy (Linac-based FSRT) and stereotactic radiosurgery (SRS) in patients with intracranial meningiomas.Materials and methodsBetween 10/1995 and 03/2009, 297 patients with a median age of 59 years were treated with FSRT for intracranial meningioma. 50 patients had a Grade I meningioma, 20 patients had a Grade II meningioma, 12 patients suffered from a Grade III tumor, and in 215 cases no histology was obtained (Grade 0). Of the 297 patients, 144 underwent FSRT as their primary treatment and 158 underwent postoperative FSRT. 179 patients received normofractionated radiotherapy (nFSRT), 92 patients received hypofractionated FSRT (hFSRT) and 26 patients underwent SRS. Patients with nFSRT received a mean total dose of 57.31 ± 5.82 Gy, patients with hFSRT received a mean total dose of 37.6 ± 4.4 Gy and patients who underwent SRS received a mean total dose of 17.31 ± 2.58 Gy.ResultsMedian follow-up was 35 months. Overall progression free survival (PFS) was 92.3% at 3 years, 87% at 5 years and 84.1% at 10 years. Patients with adjuvant radiotherapy showed significantly better PFS-rates than patients who had been treated with primary radiotherapy. There was no significant difference between PFS-rates of nFSRT, hFSRT and SRS patients. PFS-rates were independent of tumor size. Patients who had received nFSRT showed less acute toxicity than those who had received hFSRT. In the Grade 0/I group the rate of radiologic focal reactions was significantly lower than in the atypical/malignant histology group.ConclusionThis large study showed that FSRT is an effective and safe treatment modality with high PFS-rates for intracranial meningioma. We identified “pathological grading” and and “prior surgery” as significant prognostic factors.

Cochlear Radiation Dose Does Not Affect Hearing Preservation after Gamma Knife Radiosurgery in Those without Vestibular Schwannoma

Background: Radiation dose to the cochlea has been identified as a key factor in hearing preservation following stereotactic radiosurgery for vestibular schwannoma (VS). There has been little data on hearing outcomes following radiosurgery in patients with non-VS tumors located near and/or extending to the internal auditory canal (IAC). The relationship of radiation dose to the cochlea on hearing preservation in this subset of patients remains unclear. Most studies have utilized MRI-based modiolar point dose and have determined critical cutoff points between 3 to 5.3 Gy to be statistically significantly associated with loss of serviceable hearing after SRS for sporadic VS. This study was performed to assess hearing outcome for non-VS tumors receiving greater than 5 Gy modiolar point dose to the cochlea during gamma knife radiosurgery.

Symptom Distress and Quality of Life after Stereotactic Radiosurgery in Patients with Pituitary Tumors: A Questionnaire Survey

BackgroundStereotactic radiosurgery (SRS) is a common treatment for recurrent or residual pituitary adenomas. The persistence of symptoms and treatment related complications may impair the patient’s quality of life (QOL).PurposeThe purpose of this study was to examine symptom distress, QOL, and the relationship between them among patients with pituitary tumors who had undergone SRS.MethodsThis study used a cross-sectional design and purposive sampling. We enrolled patients diagnosed with pituitary tumors who had undergone SRS. Data were collected at the CyberKnife Center at a medical center in Northern Taiwan in 2012. A questionnaire survey was used for data collection. Our questionnaire consisted of 3 parts the Pituitary Tumor Symptom Distress Questionnaire, the World Health Organization Quality of Life Instrument Short-Form (WHOQOL-BREF), and a demographic questionnaire.ResultsSixty patients were enrolled in the study. The most common symptoms reported by patients after SRS were memory loss, fatigue, blurred vision, headache, sleep problems, and altered libido. The highest and lowest scores for QOL were in the environmental and psychological domains, respectively. Age was positively correlated with general health and the psychological domains. Level of symptom distress was negatively correlated with overall QOL, general health, physical health, and the psychological and social relationships domains. The scores in the psychological and environmental domains were higher in males than in females. Patients with ≤6 symptoms had better overall QOL, general health, physical health, and psychological and social relationships than those with >6 symptoms.ConclusionSymptom distress can affect different aspects of patient QOL. Levels of symptom distress, number of symptoms, age, and gender were variables significantly correlated with patient QOL. These results may be utilized by healthcare personnel to design educational and targeted interventional programs for symptom management to improve patient QOL.

EP-1045: Survival benefit of salvage radiosurgery in patients with recurrent high-grade gliomas

EP-1045: Survival benefit of salvage radiosurgery in patients with recurrent high-grade gliomas

Which Factors Determine Pain Relief From Spine Radiosurgery in Patients With Spine Metastases?: Results From a Large Single Institution Series

of care that match a patient’s wishes with potential treatment options as well as aiding in symptom management. In addition, Palliative care can provide access to hospice services when aggressive care is no longer realistic. As the very indication for WBRT remains prognostic, here we investigate the integration of palliative care in patients requiring WBRT. Materials/Methods: Patients with a solid malignancy and histologic or radiographic evidence of brain metastases who were referred to our institution between July 2011 and June 2012 were reviewed retrospectively. All patients received WBRT alone. Patient demographics, the number of emergency room visits in the last 6 months of life, and referrals to palliative care (including the referring physician) were evaluated. Results: Ninety-nine patients were diagnosed with brain metastases and treated with WBRT alone. At time of review, 85 had died, 13 were living, and 1 patient was lost to follow-up. 28 of the 85 deceased patients presented to the emergency department 2 times in the last six months of their life. Palliative care referrals were made in 67 patients. Of these referrals, 57% were during an in-patient hospitalization. The median survival after WBRTwas 64 days. The median survival after palliative care referral was 27 days. Only 26 patients were referred to palliative care during WBRT or 1 week before or after WBRT. Only 3% of patients were referred by a Radiation Oncologist. In this cohort, palliative care referral could not be correlated to age, social support, histology, or gender. Conclusions: Patients with brain metastasis requiring WBRT continue to have a predictable dying trajectory regardless of age or histology. Despite objective data to indicate a limited life expectancy, timely referrals to palliative care remain inadequate. The common pattern of care at our institution after WBRT was an acute hospital admission prompting a referral to palliative care by an inpatient service. Palliative care referrals continued to be late in the dying process and were infrequently placed by the primary oncologists. Brain metastases requiring WBRT can be used as objective criteria for the primary oncologist to engage in end of life discussions and involve palliative care services sooner. Author Disclosure: M.J. Stavas: None. K.O. Arneson: None. J.M. Friedman: None. S. Misra: None.

Time to Intracranial Failure Following Postresection Cavity Radiosurgery for Patients With a Single Intracranial Metastasis

Time to Intracranial Failure Following Postresection Cavity Radiosurgery for Patients With a Single Intracranial Metastasis

A Phase 1 Trial of Concurrent Sorafenib and Stereotactic Radiosurgery for Patients With 1-4 Brain Metastases

A Phase 1 Trial of Concurrent Sorafenib and Stereotactic Radiosurgery for Patients With 1-4 Brain Metastases

Results of Gamma Knife surgery for Cushing's disease

Cushing's disease is a challenging neuroendocrine disorder. Although resection remains the primary treatment option for most patients, the disease persists if there is residual or recurrent tumor. Stereotactic radiosurgery has been used to treat patients with persistent Cushing's disease after a prior resection. The authors report on the long-term risks and benefits of radiosurgery for Cushing's disease. A retrospective review of a prospectively collected database of radiosurgery patients was undertaken at the University of Virginia. All patients with Cushing's disease treated with Gamma Knife surgery (GKS) were identified. Those without at least 12 months of clinical and radiological follow-up were excluded from this analysis. Rates of endocrine remission, tumor control, and adverse events were assessed. Statistical methods were used to identify favorable and unfavorable prognostic factors. Ninety-six patients with the required follow-up data were identified. The mean tumor margin dose was 22 Gy. The median follow-up was 48 months (range 12-209.8 months). At the last follow-up, remission of Cushing's disease occurred in 70% of patients. The median time to remission among all patients was 16.6 months (range 1-165.7 months). The median time to remission in those who had temporarily stopped taking ketoconazole at the time of GKS was 12.6 months, whereas it was 21.8 months in those who continued to receive ketoconazole (p < 0.012). Tumor control was achieved in 98% of patients. New loss of pituitary function occurred in 36% of patients. New or worsening cranial neuropathies developed in 5 patients after GKS, with the most common involving cranial nerves II and III. Gamma Knife surgery offers a high rate of tumor control and a reasonable rate of endocrine remission in patients with Cushing's disease. The cessation of cortisol-lowering medications around the time of GKS appears to result in a more rapid rate of remission. Delayed hypopituitarism and endocrine recurrence develop in a minority of patients and underscore the need for long-term multidisciplinary follow-up.

Impact on Seizure Control of Surgical Resection or Radiosurgery for Cerebral Arteriovenous Malformations

Seizures are a common presenting symptom of arteriovenous malformations (AVMs). However, the impact of treatment modality on seizure control remains unclear. To compare seizure control after surgical resection or radiosurgery for AVMs. We analyzed retrospectively collected information for 378 patients with cerebral AVMs treated at our institution from 1990 to 2010. The application of strict inclusion criteria resulted in a study population of 164 patients. In our cohort, 31 patients (20.7%) had Spetzler-Martin grade I AVMs, 51 (34.0%) grade II, 47 (31.3%) grade III, 20 (13.3%) grade IV, and 1 (0.7%) grade V. Of the 49 patients (30%) presenting with seizures, 60.4% experienced seizure persistence after treatment. For these patients, radiosurgery was associated with seizure recurrence (odds ratio: 4.32, 95% confidence interval: 1.24-15.02, P = .021). AVM obliteration was predictive of seizure freedom at last follow-up (P = .002). In contrast, for patients presenting without seizures, 18.4% experienced de novo seizures after treatment, for which surgical resection was identified as an independent risk factor (hazard ratio: 8.65, 95% confidence interval: 3.05-24.5, P < .001). Although our data suggest that achieving seizure freedom should not be the primary goal of AVM treatment, surgical resection may result in improved seizure control compared with radiosurgery for patients who present with seizures. Conversely, in patients without presenting seizures, surgical resection increases the risk of new-onset seizures compared with radiosurgery, but primarily within the early posttreatment period. Surgical resection and radiosurgery result in divergent seizure control rates depending on seizure presentation.

Stereotactic radiosurgery in patients with multiple intracranial meningiomas

Stereotactic radiosurgery in patients with multiple intracranial meningiomas

Brachytherapy-emulating robotic radiosurgery in patients with cervical carcinoma

PurposeTo evaluate the technique, dosimetry, dose-volume-histograms (DVHs) and acute toxicity for CyberKnife® boost irradiation instead of intra-cervical brachytherapy in patients with cervical cancer.Methods and materialsEleven who were not suitable for brachytherapy with FIGO stage IIB-IIIB cervical cancer underwent primary chemoradiation. After fiducial implantation, T2 contrast-enhanced planning MRI and CT scans at 2-mm slice thickness were collected in the treatment position. The clinical target volume was defined as cervix + macroscopic residual tumour on MRI. Five fractions of 6 Gy each were prescribed to the target volume with a covering single dose 6 Gy. DVH parameters were evaluated for the target and organs at risk. Acute toxicity was documented once a week.ResultsDmeanPTV ranged from 33.6-40 Gy, median 36.7 Gy with a coverage of the PTV calculated to 100% of the prescribed dose ranging from 93.0-99.3% (median 97.7%). For the PTV the median CN was 0.78 (range, 0.66 to 0.87) and the median CI was 1.28 (range 1.15 to 1.52). Gastrointestinal (GI) and genitourinary (GU) toxicity was mild. There was no grade 3 or higher GI and GU toxicity. After 6 months of follow up, there were no local recurrences. For the complete treatment, a median EQD2 to 1 cc and 2 cc of the bladder wall was 98.8 Gy and 87.1 Gy, respectively. Median EQD2 to 1 cc and 2 cc of the rectal wall was 72.3 Gy and 64 Gy, respectively, correlating with a risk < 10% for Grade 2–4 late toxicity.ConclusionsCyberKnife robotic radiosurgery in patients with cervical cancer provides excellent target coverage with steep dose gradients toward normal tissues and safe DVH parameters for bladder, rectum and sigmoid. Acute toxicity was mild. Longer follow-up is needed to evaluate the oncological equality.

Editorial: Multiple metastases

Authors from the University of Virginia provide their analysis of clinical outcomes following stereotactic radiosurgery in patients with 5–15 metastases.1 Their study included 96 patients managed over a 10-year period. It excluded patients with more than 15 tumors, but it was unclear if they did indeed provide radiosurgery to selected patients with more than 15 tumors who were excluded from their report. Clinical outcomes focused on an evaluation of some of the standard features used in the brain metastasis literature. These include patient age, patient sex, Karnofsky Performance Status score, recursive and graded partitioning analysis scores, control of the primary tumor, prior chemotherapy or resection, prior wholebrain radiation therapy, tumor histology, and subsequent treatment. They found that the Recursive Partitioning Analysis (RPA) class correlated with outcome in this patient population. That classification includes the features of age and extracranial disease status and thus logically would correlate with outcome. In the last decade, the concept of treating more and more tumors using radiosurgery has been explored. What was once considered heresy 20 years ago when a “focused procedure” was used for an “unfocused disease,” radiosurgery has been shown in initial randomized trials to provide local tumor control benefits in patients with 2, 3, or 4 tumors. In an analysis in patients with more than 4, we found that it was not the number of tumors that was important but the total tumor volume of all brain metastases. If that volume was less than 7.5 cm3, the median survival was similar to that typically expected with 1 tumor (12 months). Thus, volume is a much clearer surrogate for cancer burden than tumor number. This is why Salvetti and colleagues found that patients who had between 5 and 9 tumors fared similarly to those with more than 9. There is a growing body of literature on the value of radiosurgery in properly selected patients with multiple brain metastases who are being actively managed for their extracranial cancer. In prior years, such patients would simply have been left on a palliative path with little more than whole-brain radiation therapy. In many such patients, whole-brain radiation may have already been delivered, and no further active brain tumor treatment was offered. Based on the study by Salvetti and colleagues, for patients in RPA Class 1 or 2 in whom improved survival can be expected, stereotactic radiosurgery can play an important role in those with more than 5 tumors. Because current payment paradigms limit reimbursement at 5 tumors, payment for more tumors should be reevaluated. (http://thejns.org/doi/abs/10.3171/2012.11.JNS121813)

Predicting Survival in Patients With Brain Metastases Treated With Radiosurgery Using Artificial Neural Networks

Artificial neural networks (ANNs) excel at analyzing challenging data sets and can be exceptional tools for decision support in clinical environments. The present study pilots the use of ANNs for determining prognosis in neuro-oncology patients. To determine whether ANNs perform better at predicting 1-year survival in a group of patients with brain metastasis compared with traditional predictive tools. : ANNs were trained on a multi-institutional data set of radiosurgery patients to predict 1-year survival on the basis of several input factors. A single ANN, an ensemble of 5 ANNs, and logistic regression analyses were compared for efficacy. Sensitivity analysis was used to identify important variables in the ANN model. A total of 196 patients were divided up into training, testing, and validation data sets consisting of 98, 49, and 49 patients, respectively. Patients surviving at 1 year tended to be female (P = .001) and of good performance status (P = .01) and to have favorable primary tumor histology (P = .001). The pooled voting of 5 ANNs performed significantly better than the multivariate logistic regression model (P = .02), with areas under the curve of 84% and 75%, respectively. The ensemble also significantly outperformed 2 commonly used prognostic indexes. Primary tumor subtype and performance status were identified on sensitivity analysis to be the most important variables for the ANN. ANNs outperform traditional statistical tools and scoring indexes for predicting individual patient prognosis. Their facile implementation, robustness in the presence of missing data, and ability to continuously learn make them excellent choices for use in complicated clinical environments.

Role of stereotactic radiosurgery in patients with more than four brain metastases

For patients presenting with brain metastases, two methods of radiation treatment currently exist: stereotactic radiosurgery (SRS) and whole-brain radiation therapy (WBRT). SRS is a minimally invasive to noninvasive technique that delivers a high dose of ionizing radiation to a precisely defined focal target volume, whereas WBRT involves multiple smaller doses of radiation delivered to the whole brain. Evidence exists from randomized controlled trials for SRS in the treatment of patients with one to four brain metastases. Patients with more than four brain metastases generally receive WBRT, which can effectively treat undetected metastases and protect against intracranial relapse. However, WBRT has been associated with an increased potential for toxic neurocognitive side effects, including memory loss and early dementia, and does not provide 100% protection against relapse. For this reason, physicians at many medical centers are opting to use SRS as first-line treatment for patients with more than four brain metastases, despite evidence showing an increased rate of intracranial relapse compared with WBRT. In light of the evolving use of SRS, this review will examine the available reports on institutional trials and outcomes for patients with more than four brain metastases treated with SRS alone as first-line therapy.

Robotic Stereotactic Radiosurgery in Patients with Nasal Cavity and Paranasal Sinus Tumors

The aim of this retrospective study is to evaluate our therapeutic results in patients with paranasal sinus (PNS) or nasal cavity (NC) malignancies treated with robotic stereotactic radiosurgery (SRS). Between August 2007 and October 2008, 27 patients with PNS or NC tumors were treated in our department using SRS. Median age was 53 years (range, 27-84 years). Eleven patients were female and sixteen were male. Most common histopathology was SCC (44%). The disease involved the maxillary sinus in 15 patients (55%). SRS was applied to 6 patients (22%) for reirradiation, while the others received it as a primary treatment. Seven patients had SRS as a boost dose to external beam radiotherapy. SRS was delivered with cyberknife (Accuray Incorporated, Sunnyvale, CA, USA). The median dose to the tumor was 31 Gy (range, 15-37.5 Gy) in median 5 fractions (range, 3-5 fractions). After a median follow-up of 21.4 months (range, 3-59 months), 76% of the patients were free of local relapse. Three patients showed local progression and 3 developed distant metastases. One- and two-year survival rates for the entire group were 95.2% (SEM = 0.046) and 77.1% (SEM = 0.102), respectively. We observed brain necrosis in 2 patients, visual disorder in 2 patients, bone necrosis in 2 patients and trismus in 1 patient as a SRS related late toxicity. Robotic SRS seems to be a feasible treatment strategy for patients with PNS tumors. Further prospective studies with longer follow up times should be performed.

Dosimetric Accuracy of Ray-tracing Algorithm for Treatment of Thoracic Spine Lesions Using Robotic Radiosurgery

Dosimetric Accuracy of Ray-tracing Algorithm for Treatment of Thoracic Spine Lesions Using Robotic Radiosurgery

CyberKnife Radiosurgery for the Treatment of Orbital Metastases

Purpose of this study is to evaluate radiographic therapy response, clinical outcome and adverse effects of CyberKnife radiosurgery in patients suffering from orbital metastases. Sixteen orbital metastases originating from different solid cancers in fourteen patients were treated by single fraction CyberKnife radiosurgery. Radiographic response and clinical outcome were evaluated. The treated tumor volume ranged from 0.2 to 35 cm3 (median 2.3 cm3, mean 7.0 cm3, SD 6 10.4 cm3, CI 0.9-9.4 cm3). The prescription dose ranged from 16.5-21 Gy (median 18 Gy, mean 18.2 Gy, SD 6 1.2 Gy, CI 17.0-18.4 Gy). A no change situation was observed in nine lesions, partial remission in four as well as complete remission in one metastasis. Tumor growth was stabilized or regressive following CyberKnife therapy in 87% of the cases. Recurrence was observed in two cases (13%). Before therapy, three patients suffered from visual disturbance and five patients reported diplopia. Six patients had no initial symptoms. After therapy, one patient indicated improvement of the present visual deficit and two patients no change. Out of the two patients with persistent diplopia, two reported improvement after therapy and three no change. No progression of symptoms was noted in any of the cases. Fourteen out of sixteen treated lesions were stable or regressive following CyberKnife radiosurgery (87%). As no serious adverse effects were reported in this series, CyberKnife therapy was shown to be of great value for local management of orbital metastases.

26IN - Brain Metastasis: Challenges in Understanding Pathogenesis and in Designing Clinical Trials

ABSTRACT The presence of brain metastases (BM) remains a therapeutic challenge as most trials with the exception of local treatment with surgery and radiosurgery in patients with solitary BM have failed. The negative trials suggest that the disease in the brain is not the principal determinant of life expectancy in patients with disseminated disease. Large trials without enrichment of the study population by a predictive biomarker are also unlikely to be successful. The blanket use of whole brain radiotherapy for multiple BMs is also no longer tenable. The concept of blood brain barrier, unlikely to be of significance in patients with enhancing brain metastases, should not be a bar to the use of chemotherapy, where the principal determinant of efficacy is likely to be chemoresponsiveness of systemic disease. Successful use of prophylactic brain treatment is predicated on the assumption that brain dissemination is a late metastatic event. Metastases suppressors, with mode of action spanning the metastatic cascade, have prophylactic efficacy in vivo, although the studies are mostly based on non-spontaneous models, which are unlikely to reflect the true clinical situation. Nevertheless some agents are approaching the time of clinical application. The successful development of new therapies for BMs needs refinement of the current trial design. Phase I/II studies of new agents should not exclude patients with BM to provide “proof of principle” of therapeutic efficacy in the brain. Subsequent trials, with survival as the primary endpoint, should focus on patient population where BM are likely to be the determinants of outcome (i.e. with inactive systemic disease) and enriched for a predictive biomarker. Large trials, even in a single tumour type, testing a single agent or a combination, either alone or in addition to standard treatment without appropriate patient selection are likely to continue to fail. Disclosure The author has declared no conflicts of interest.

Mechanisms and prevention of thermal injury from gamma radiosurgery headframes during 3T MR imaging

Magnetic resonance imaging (MRI) is regularly used for stereotactic imaging of Gamma Knife (GK) radiosurgery patients for GK treatment planning. MRI‐induced thermal injuries have occurred and been reported for GK patients with attached metallic headframes. Depending on the specific MR imaging and headframe conditions, a skin injury from MRI‐induced heating can potentially occur where the four headframe screws contact the skin surface of the patient's head. Higher MR field strength has a greater heating potential. Two primary heating mechanisms, electromagnetic induction and the antenna effect, are possible. In this study, MRI‐induced heating from a 3T clinical MRI scanner was investigated for stereotactic headframes used in gamma radiosurgery and neurosurgery. Using melons as head phantoms, optical thermometers were used to characterize the temperature profile at various points of the melon headframe composite as a function of two 3T MR pulse sequence protocols. Different combinations of GK radiosurgery headframe post and screw designs were tested to determine best and worst combinations for MRI‐induced heating. Temperature increases were measured for all pulse sequences tested, indicating that the potential exists for MRI‐induced skin heating and burns at the headframe attachment site. This heating originates with electromagnetic induction caused by the RF fields inducing current in a loop formed by the headframe, mounting screws, and the region of the patient's head located between any of the two screws. This induced current is then resistively dissipated, with the regions of highest resistance, located at the headframe screw–patient head interface, experiencing the most heating. Significant heating can be prevented by replacing the metallic threads holding the screw with electrically insulated nuts, which is the heating prevention and patient safety recommendation of the GK manufacturer. Our results confirm that the manufacturer's recommendation to use insulating nuts reduces the induced currents in the headframe nearly to zero, effectively preventing heating and minimizing the likelihood of thermal injury.PACS numbers: 87.57.‐s, 87.61.‐c, 87.61.Tg, 87.57.c‐

SU-E-T-410: Spine Radiosurgery Imaging Guidance Using ExacTrac and CT on rails.

To evaluate the patient setup accuracy and effectiveness using ExacTrac and CT_on_rails systems. We used Brainlab's Exactrac system and Varian/GE's CT_on_rails for spine radiosurgery patient setup. Once the patient was setup using the ExacTrac and couch position was recorded, fiducially markers were placed on stable surfaces based on the room laser to indicate the linac iso for the CT images. CT images were acquired using the on-rail CT with the couch rotated 180 degrees. The couch was returned to 0 degree position, and verification X-ray images were taken and corrections were made by ExacTrac. The treatment CT images were registered with the planning CT using the in-house CAT software and it displays the correct couch position based on CT which can be compared with ExacTrac setup. The corrected couch positions from CT registration are compared to those from ExacTrac. The translational discrepancies needed to be within 2 mm for confirmation. If a discrepancy was greater than 2 mm, investigation or re-setup was required. The rotation deviations were also evaluated by ExacTrac and confirmed by the treatment CT images. We would also re-setup patient if Exactrac detected more than 3 degree rotation, or treatment CT images showed significant target rotation compared to planning CT. The use of the CTonrails took little extra time, but make the overall evaluation process easier, faster and with more confidence. for 171 treatment sessions using this approach, the mean discrepancies between CTonrails and ExacTrac setup is: x=0.0±1.0 mm, y=-0. 1±0.9 mm, z=0.2±0.9 mm; for rotations, about 3% of the cases required re-setup patient due to significant rotation displayed by the treatment CT on the CAT system. The combined use of ExacTrac and CT_on_Rails systems can improve the overall setup accuracy and increase the confidence in setup for spine radiosurgery treatments.