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Gregory J Gagnon - One of the best experts on this subject based on the ideXlab platform.
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treatment of spinal tumors using Cyberknife fractionated stereotactic radiosurgery pain and quality of life assessment after treatment in 200 patients
Neurosurgery, 2009Co-Authors: Gregory J Gagnon, Nadim M Nasr, Jay J Liao, Inge Molzahn, David M Marsh, Donald A Mcrae, Fraser C HendersonAbstract:OBJECTIVE: Benign and malignant tumors of the spine significantly impair the function and quality of life of many patients. Standard treatment options, including conventional radiotherapy and surgery, are often limited by anatomic constraints and prior treatment. Image-guided stereotactic radiosurgery using the Cyberknife system (Accuray, Inc., Sunnyvale, CA) is a novel approach in the multidisciplinary management of spinal tumors. The aim of this study was to evaluate the effects of Cyberknife stereotactic radiosurgery on pain and quality-of-life outcomes of patients with spinal tumors. METHODS: We conducted a prospective study of 200 patients with benign or malignant spinal tumors treated at Georgetown University Hospital between March 2002 and September 2006. Patients were treated by means of multisession stereotactic radiosurgery using the Cyberknife as initial treatment, postoperative treatment, or retreatment. Pain scores were assessed by the Visual Analog Scale, quality of life was assessed by the SF-12 survey, and neurological examinations were conducted after treatment. RESULTS: Mean pain scores decreased significantly from 40.1 to 28.6 after treatment (P 0.001) and continued to decrease over the entire 4-year follow-up period (P 0.05). SF-12 Physical Component scores demonstrated no significant change throughout the follow-up period. Mental Component scores were significantly higher after treatment (P 0.01), representing a quality-of-life improvement. Early side effects of radiosurgery were mild and self-limited, and no late radiation toxicity was observed. CONCLUSION: Cyberknife stereotactic radiosurgery is a safe and effective modality in the treatment of patients with spinal tumors. Cyberknife offers durable pain relief and maintenance of quality of life with a very favorable side effect profile.
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Cyberknife radiosurgery for breast cancer spine metastases a matched pair analysis
Cancer, 2007Co-Authors: Gregory J Gagnon, Brian T Collins, Fraser C Henderson, Edmund A Gehan, Donna Sanford, Jefferson Moulds, Anatoly DritschiloAbstract:BACKGROUND. There are few options for breast cancer patients with spinal metastases recurrent within a previous radiation treatment field. Cyberknife radiosurgery has been used in our institution to treat such patients. To evaluate their outcomes, as there are no comparable radiation treatment options, the outcomes were compared between 18 patients with spinal metastases from breast cancer treated with Cyberknife stereotactic radiosurgery, 17 of which had prior radiotherapy to the involved spinal region and were progressing, and 18 matched patients who received conventional external beam radiotherapy (CRT) up-front for spinal metastases. METHODS. Radiosurgery was delivered in 3 to 5 fractions to doses ranging from 2100 to 2800 cGy. Women were matched to patients in a CRT group with respect to time from original diagnosis to diagnosis of metastases, estrogen receptor / progesterone receptor (ER/PR) status, presence or absence of visceral metastases, prior radiotherapy, and prior chemotherapy. Survival and complications were compared between treatment groups. Surviving patients were followed out to 24 months. RESULTS. The Cyberknife and CRT groups were comparable along all matching dimensions and in performance status before treatment. Outcomes of treatment were similar for patients in both groups; ambulation, performance status, and pain worsened similarly across groups posttreatment. Survival and the number of complications appeared to favor the Cyberknife group, but the differences did not reach statistical significance. CONCLUSIONS. The statistical comparability of the Cyberknife and CRT groups reflects the small sample size and stringent requirements for significance of the matched-pair analysis. Nevertheless, comparability in these difficult cases shows that salvage Cyberknife treatment is as efficacious as initial CRT without added toxicity. Cancer 2007. © 2007 American Cancer Society.
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eus guided fiducial placement for Cyberknife radiotherapy of mediastinal and abdominal malignancies
Gastrointestinal Endoscopy, 2006Co-Authors: Aline Charabaty Pishvaian, Brian T Collins, Gregory J Gagnon, Sushil Ahlawat, Nadim HaddadAbstract:Background The Cyberknife frameless image-guided stereotactic radiosurgery system delivers radiation doses to tumors with high precision by use of real-time image guidance. Radiographic markers (or fiducials) implanted at the tumor site are used as reference points by the system to target the radiation beams. Diagnostic and interventional EUS have multiple applications in the multidisciplinary approach to tumors. Objective The goal of this prospective study was to evaluate the safety and feasibility of placing fiducials in mediastinal and intra-abdominal tumors under EUS guidance. Design Patients were evaluated for EUS-guided fiducial placement. A linear echoendoscope was used to localize the tumor, insert a 19-gauge fine needle in the target area, and place the fiducials through the needle lumen. The position of the fiducials was verified by EUS and by fluoroscopy. Setting Georgetown University Hospital, between February 2005 and August 2005. Patients Thirteen patients scheduled to undergo Cyberknife radiation therapy. Results EUS-guided fiducial placement was successful in a total of 11 of 13 patients (84.6%). The locations of the tumors were as follows: retrocrural area at the dome of the diaphragm, porta hepatis, gastroesophageal junction, mediastinum, thoracic paraspinal area, and pancreas. A total of 3 to 6 fiducials were placed in each patient. An infectious complication developed in 1 patient within 30 days of the procedure. Conclusion EUS-guided fiducial placement in lesions of the mediastinum and abdomen is a feasible and safe technique that can be used to mark a tumor site and guide Cyberknife radiation therapy. This new application of interventional EUS further expands the role of EUS in the multidisciplinary approach to the oncology patient.
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Cyberknife stereotactic radiosurgical treatment of spinal tumors for pain control and quality of life
Journal of Neurosurgery, 2005Co-Authors: Jeffrey W Degen, Gregory J Gagnon, Inge Molzahn, Donald A Mcrae, Sonja Dieterich, Jean Marc Voyadzis, Michael Lunsden, Fraser C HendersonAbstract:Object. The authors conducted a study to assess safety, pain, and quality of life (QOL) outcomes following Cyberknife radiosurgical treatment of spinal tumors. Methods. Data obtained in all patients with spinal tumors who underwent Cyberknife radiosurgery at Georgetown University Hospital between March 2002 and March 2003 were analyzed. Patients underwent examination, visual analog scale (VAS) pain assessment, and completed the 12-item Short Form Health Survey (SF-12) before treatment and at 1, 3, 6, 8, 12, 18, and 24 months following treatment. Fifty-one patients with 72 lesions (58 metastatic and 14 primary) were treated. The mean follow-up period was 1 year. Pain was improved, with the mean VAS score decreasing significantly from 51.5 to 21.3 at 4 weeks (p < 0.001). This effect on pain was durable, with a mean score of 17.5 at 1 year, which was still significantly decreased (p = 0.002). Quality of life was maintained throughout the study period. After 18 months, physical well-being was 33 (initial scor...
L Fariselli - One of the best experts on this subject based on the ideXlab platform.
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multi institutional application of failure mode and effects analysis fmea to Cyberknife stereotactic body radiation therapy sbrt
Radiation Oncology, 2015Co-Authors: Ivan Veronese, A S Martinotti, Maria Luisa Fumagalli, Cristina Vite, I Redaelli, Guillaume Beltramo, Tiziana Malatesta, Elena Martin, Pietro Mancosu, L FariselliAbstract:Background A multidisciplinary and multi-institutional working group applied the Failure Mode and Effects Analysis (FMEA) approach to assess the risks for patients undergoing Stereotactic Body Radiation Therapy (SBRT) treatments for lesions located in spine and liver in two Cyberknife® Centres.
Fujio Araki - One of the best experts on this subject based on the ideXlab platform.
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monte carlo study of a Cyberknife stereotactic radiosurgery system
Medical Physics, 2006Co-Authors: Fujio ArakiAbstract:This study investigated small-field dosimetry for a Cyberknife stereotactic radiosurgery system using Monte Carlo simulations. The EGSnrc/BEAMnrc Monte Carlo code was used to simulate the Cyberknife treatment head, and the DOSXYZnrc code was implemented to calculate central axis depth-dose curves, off-axis dose profiles, and relative output factors for various circular collimator sizes of 5 to 60 mm . Water-to-air stopping power ratios necessary for clinical reference dosimetry of the Cyberknife system were also evaluated by Monte Carlo simulations. Additionally, a beam quality conversion factor, k Q , for the Cyberknife system was evaluated for cylindrical ion chambers with different wall material. The accuracy of the simulated beam was validated by agreement within 2% between the Monte Carlo calculated and measured central axis depth-dose curves and off-axis dose profiles. The calculated output factors were compared with those measured by a diode detector and an ion chamber in water. The diode output factors agreed within 1% with the calculated values down to a 10 mm collimator. The output factors with the ion chamber decreased rapidly for collimators below 20 mm . These results were confirmed by the comparison to those from Monte Carlo methods with voxel sizes and materials corresponding to both detectors. It was demonstrated that the discrepancy in the 5 and 7.5 mm collimators for the diode detector is due to the water nonequivalence of the silicon material, and the dose fall-off for the ion chamber is due to its large active volume against collimators below 20 mm . The calculated stopping power ratios of the 60 mm collimator from the Cyberknife system (without a flattening filter) agreed within 0.2% with those of a 10 × 10 cm 2 field from a conventional linear accelerator with a heavy flattening filter and the incident electron energy, 6 MeV . The difference in the stopping power ratios between 5 and 60 mm collimators was within 0.5% at a 10 cm depth in water. Furthermore, k Q values for the Cyberknife system were in agreement within 0.3% with those of the conventional 6 MV -linear accelerator for the cylindrical ion chambers with different wall material.
Sonja Dieterich - One of the best experts on this subject based on the ideXlab platform.
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experimental comparison of seven commercial dosimetry diodes for measurement of stereotactic radiosurgery cone factors
Medical Physics, 2011Co-Authors: Sonja Dieterich, George W SherouseAbstract:Purpose: The purpose of this work is to assess the variation in performance of various commercially available dosimetry diodes for quantitative small field dosimetry, specifically by intercomparing measurements of SRS cone factors. Methods: Measurements were made in 6 MV photon beams with fixed SRS cones for two accelerator-based SRS systems: a Varian Clinac iX (Varian/Zmed cones) at 600 MU/min and a Cyberknife model G4 at 800 MU/min. Measurements were made at 1.5 cm depth in water using the IBA Dosimetry ''blue phantom'' 3D scanning system, controlled by omnipro-accept software. Source-to-detector distance was 100 cm for the Clinac, 80 cm for the Cyberknife. Two normalization methods were used for the Clinac, one directly referenced to diode measurements in a 10 cm x 10 cm square field and the other indirectly by ''daisy-chaining'' diode measurements to ion chamber measurement in the 10 cm x 10 cm reference field through an intermediate 4 cm x 4 cm square field. Cyberknife factors were referenced directly to measurements in the 60 mm reference field. Seven commercial diodes were evaluated: PTW TN60008, TN60012, TN60016, TN60017; IBA Dosimetry SFD; Sun Nuclear EDGE; Exradin SD1 (first generation prototype). Results: With the exception of the SFD, all the evaluatedmore » devices yielded surprisingly consistent results. Standard deviations of Clinac factors for four diodes (SD1, EDGE, TN60008, and TN60012) ranged from approximately 0.50% at 30 mm to 2.0% at 5 mm cones size when referenced directly to the 10 cm x 10 cm measurement. The daisy-chaining strategy reduced the standard deviation to approximately 0.30% at 30 mm and 1.9% at 5 mm. Standard deviations for the same four diodes in the Cyberknife beam ranged up to approximately 1.0% at 5 mm. Conclusions: The inter-detector variation is small and appears to be systematic with detector packaging, more inherent filtration producing flatter curves for both the relatively hard Clinac beam and the softer Cyberknife beam. The daisy-chain strategy appears to be of limited value for most of the diodes, but does bring the SFD results into significantly better agreement with the others.« less
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su gg t 442 dose verification of srs monte carlo plan with a moving anthropomorphic phantom
Medical Physics, 2010Co-Authors: Sonja DieterichAbstract:Purpose: Dose verification of Stereotactic Radiosurgery plan using Monte Carlo for tissue heterogeneity correction with a moving anthropomorphic phantom Method and Materials: An anthropomorphic lung phantom has gold fiducials, TLD capsules and GAFChromic films imbedded in a target in the left lung,TLD capsules are also inserted in heart and cord structures. The phantom was scanned, CT images were sent to Cyberknife Multiplan for planning. Target and critical structures were contoured. A SRS treatment plan with no tissue heterogeneity correction was generated to give 6Gy to 95% of the target, 5.4Gy to 99% of the target, no point > 2cm from target > 3.5Gy, conformai index < 1.2, cord < 1.8Gy, heart < 3Gy, 10% of whole lung < 2Gy. The plan was recalculated with Monte Carlo with 2% uncertainty for tissue heterogeneity correction for dose delivery. During delivery the phantom moved in superior/inferior and anterior/posterior direction, Cyberknife Synchrony tracking system took orthogonal x‐ray images of the phantom while infra‐red camera tracked LED diodes placed on the phantom to track phantom motion in real time. After the fiducials were identified by the tracking program and correlated with the motion of LED diodes, a motion model of the target was built; radiation started with the Cyberknife robot following the predicted target motion and adjusted its position during irradiation. Throughout delivery, the motion model was updated and adjusted with new x‐ray images of the fiducials. Results: Target TLD was 98.3% of Monte Carlodose;heart and cord TLD were within 7% acceptability. Profiles from 3 orthogonal films were displaced L/R 0mm/3mm, P/A 1mm/5mm and I/S 1mm/2mm from treatment plan profiles, within 5mm acceptability. Conclusion: Cyberknife Multiplan with Monte Carlo accurately predicts dose in heterogeneous tissue; Cyberknife Synchrony tracking system delivers dose accurately to a target in a moving phantom.
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Cyberknife stereotactic radiosurgical treatment of spinal tumors for pain control and quality of life
Journal of Neurosurgery, 2005Co-Authors: Jeffrey W Degen, Gregory J Gagnon, Inge Molzahn, Donald A Mcrae, Sonja Dieterich, Jean Marc Voyadzis, Michael Lunsden, Fraser C HendersonAbstract:Object. The authors conducted a study to assess safety, pain, and quality of life (QOL) outcomes following Cyberknife radiosurgical treatment of spinal tumors. Methods. Data obtained in all patients with spinal tumors who underwent Cyberknife radiosurgery at Georgetown University Hospital between March 2002 and March 2003 were analyzed. Patients underwent examination, visual analog scale (VAS) pain assessment, and completed the 12-item Short Form Health Survey (SF-12) before treatment and at 1, 3, 6, 8, 12, 18, and 24 months following treatment. Fifty-one patients with 72 lesions (58 metastatic and 14 primary) were treated. The mean follow-up period was 1 year. Pain was improved, with the mean VAS score decreasing significantly from 51.5 to 21.3 at 4 weeks (p < 0.001). This effect on pain was durable, with a mean score of 17.5 at 1 year, which was still significantly decreased (p = 0.002). Quality of life was maintained throughout the study period. After 18 months, physical well-being was 33 (initial scor...
Fraser C Henderson - One of the best experts on this subject based on the ideXlab platform.
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treatment of spinal tumors using Cyberknife fractionated stereotactic radiosurgery pain and quality of life assessment after treatment in 200 patients
Neurosurgery, 2009Co-Authors: Gregory J Gagnon, Nadim M Nasr, Jay J Liao, Inge Molzahn, David M Marsh, Donald A Mcrae, Fraser C HendersonAbstract:OBJECTIVE: Benign and malignant tumors of the spine significantly impair the function and quality of life of many patients. Standard treatment options, including conventional radiotherapy and surgery, are often limited by anatomic constraints and prior treatment. Image-guided stereotactic radiosurgery using the Cyberknife system (Accuray, Inc., Sunnyvale, CA) is a novel approach in the multidisciplinary management of spinal tumors. The aim of this study was to evaluate the effects of Cyberknife stereotactic radiosurgery on pain and quality-of-life outcomes of patients with spinal tumors. METHODS: We conducted a prospective study of 200 patients with benign or malignant spinal tumors treated at Georgetown University Hospital between March 2002 and September 2006. Patients were treated by means of multisession stereotactic radiosurgery using the Cyberknife as initial treatment, postoperative treatment, or retreatment. Pain scores were assessed by the Visual Analog Scale, quality of life was assessed by the SF-12 survey, and neurological examinations were conducted after treatment. RESULTS: Mean pain scores decreased significantly from 40.1 to 28.6 after treatment (P 0.001) and continued to decrease over the entire 4-year follow-up period (P 0.05). SF-12 Physical Component scores demonstrated no significant change throughout the follow-up period. Mental Component scores were significantly higher after treatment (P 0.01), representing a quality-of-life improvement. Early side effects of radiosurgery were mild and self-limited, and no late radiation toxicity was observed. CONCLUSION: Cyberknife stereotactic radiosurgery is a safe and effective modality in the treatment of patients with spinal tumors. Cyberknife offers durable pain relief and maintenance of quality of life with a very favorable side effect profile.
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Cyberknife radiosurgery for breast cancer spine metastases a matched pair analysis
Cancer, 2007Co-Authors: Gregory J Gagnon, Brian T Collins, Fraser C Henderson, Edmund A Gehan, Donna Sanford, Jefferson Moulds, Anatoly DritschiloAbstract:BACKGROUND. There are few options for breast cancer patients with spinal metastases recurrent within a previous radiation treatment field. Cyberknife radiosurgery has been used in our institution to treat such patients. To evaluate their outcomes, as there are no comparable radiation treatment options, the outcomes were compared between 18 patients with spinal metastases from breast cancer treated with Cyberknife stereotactic radiosurgery, 17 of which had prior radiotherapy to the involved spinal region and were progressing, and 18 matched patients who received conventional external beam radiotherapy (CRT) up-front for spinal metastases. METHODS. Radiosurgery was delivered in 3 to 5 fractions to doses ranging from 2100 to 2800 cGy. Women were matched to patients in a CRT group with respect to time from original diagnosis to diagnosis of metastases, estrogen receptor / progesterone receptor (ER/PR) status, presence or absence of visceral metastases, prior radiotherapy, and prior chemotherapy. Survival and complications were compared between treatment groups. Surviving patients were followed out to 24 months. RESULTS. The Cyberknife and CRT groups were comparable along all matching dimensions and in performance status before treatment. Outcomes of treatment were similar for patients in both groups; ambulation, performance status, and pain worsened similarly across groups posttreatment. Survival and the number of complications appeared to favor the Cyberknife group, but the differences did not reach statistical significance. CONCLUSIONS. The statistical comparability of the Cyberknife and CRT groups reflects the small sample size and stringent requirements for significance of the matched-pair analysis. Nevertheless, comparability in these difficult cases shows that salvage Cyberknife treatment is as efficacious as initial CRT without added toxicity. Cancer 2007. © 2007 American Cancer Society.
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Cyberknife stereotactic radiosurgical treatment of spinal tumors for pain control and quality of life
Journal of Neurosurgery, 2005Co-Authors: Jeffrey W Degen, Gregory J Gagnon, Inge Molzahn, Donald A Mcrae, Sonja Dieterich, Jean Marc Voyadzis, Michael Lunsden, Fraser C HendersonAbstract:Object. The authors conducted a study to assess safety, pain, and quality of life (QOL) outcomes following Cyberknife radiosurgical treatment of spinal tumors. Methods. Data obtained in all patients with spinal tumors who underwent Cyberknife radiosurgery at Georgetown University Hospital between March 2002 and March 2003 were analyzed. Patients underwent examination, visual analog scale (VAS) pain assessment, and completed the 12-item Short Form Health Survey (SF-12) before treatment and at 1, 3, 6, 8, 12, 18, and 24 months following treatment. Fifty-one patients with 72 lesions (58 metastatic and 14 primary) were treated. The mean follow-up period was 1 year. Pain was improved, with the mean VAS score decreasing significantly from 51.5 to 21.3 at 4 weeks (p < 0.001). This effect on pain was durable, with a mean score of 17.5 at 1 year, which was still significantly decreased (p = 0.002). Quality of life was maintained throughout the study period. After 18 months, physical well-being was 33 (initial scor...
