Synchrony – Cyberknife Respiratory Compensation Technology

Ozhasoglu, Cihat; Saw, Cheng B.; Chen, Hungcheng; Burton, Steven A.; Komanduri, Krishna; Yue, Ning J.; Huq, S.; Heron, Dwight E.

doi:10.1016/j.meddos.2008.02.004

Cited by 91 publications

(86 citation statements)

References 18 publications

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“…Thus, various methods have been devised to compensate for motion, including dynamic multileaf collimator (DMLC) tracking (4) and the use of a robotic arm with six axes (5) . The CyberKnife system (Accuray Inc., Sunnyvale, CA) uses image guidance with two pairs of X‐ray tubes and a flat‐panel detector to detect bone anatomy, fiducial marker position, and tumor position according to image densities (6) .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of tracking accuracy of the CyberKnife system using a webcam and printed calibrated grid

Sumida

Shiomi

Higashinaka³

et al. 2016

J Applied Clin Med Phys

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Tracking accuracy for the CyberKnife's Synchrony system is commonly evaluated using a film‐based verification method. We have evaluated a verification system that uses a webcam and a printed calibrated grid to verify tracking accuracy over three different motion patterns. A box with an attached printed calibrated grid and four fiducial markers was attached to the motion phantom. A target marker was positioned at the grid's center. The box was set up using the other three markers. Target tracking accuracy was evaluated under three conditions: 1) stationary; 2) sinusoidal motion with different amplitudes of 5, 10, 15, and 20 mm for the same cycle of 4 s and different cycles of 2, 4, 6, and 8 s with the same amplitude of 15 mm; and 3) irregular breathing patterns in six human volunteers breathing normally. Infrared markers were placed on the volunteers’ abdomens, and their trajectories were used to simulate the target motion. All tests were performed with one‐dimensional motion in craniocaudal direction. The webcam captured the grid's motion and a laser beam was used to simulate the CyberKnife's beam. Tracking error was defined as the difference between the grid's center and the laser beam. With a stationary target, mean tracking error was measured at 0.4 mm. For sinusoidal motion, tracking error was less than 2 mm for any amplitude and breathing cycle. For the volunteers’ breathing patterns, the mean tracking error range was 0.78‐1.67 mm. Therefore, accurate lesion targeting requires individual quality assurance for each patient.PACS number(s): 87.55.D‐, 87.55.km, 87.55.Qr, 87.56.Fc

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Section: Introductionmentioning

confidence: 99%

Evaluation of tracking accuracy of the CyberKnife system using a webcam and printed calibrated grid

Sumida

Shiomi

Higashinaka³

et al. 2016

J Applied Clin Med Phys

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“…The Synchrony treatment planning procedure recommended by manufacturer and described in detail by Ozhasoglu et al ( 16 ) was used in this study. Since the CyberKnife Synchrony system can track the tumor during respiratory motion, the manufacturer recommends that the

{GTV}_{Cyber}

is contoured on an end‐exhalation breath‐hold CT scan, which is similar to the 50% phase (maximum exhalation phase) of 4D CT images.…”

Section: Methodsmentioning

confidence: 99%

“…By matching fiducial markers or bony anatomy from kV X‐ray images to DRRs generated from CT simulation, the resulting setup errors (three translations and three rotations) can be determined and compensated either automatically or manually by a therapist. Synchrony Respiratory Tracking system (Accuray Inc., Sunnyvale, CA) is an integrated tumor tracking component of the CyberKnife system ( 16 ) that allows dynamic compensation for respiratory motion. The tumor position, which is determined through kV X‐ray visualization of adjacent fiducial markers, is correlated with the location of external markers using an adaptive model.…”

Section: Introductionmentioning

confidence: 99%

A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac‐based systems

Ding

Chang

Haslam

et al. 2010

J Applied Clin Med Phys

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The aim of this study is to compare the dosimetric characteristics of robotic and conventional linac‐based SBRT techniques for lung cancer, and to provide planning guidance for each modality. Eight patients who received linac‐based SBRT were retrospectively included in this study. A dose of 60 Gy given in three fractions was prescribed to each target. The Synchrony Respiratory Tracking System and a 4D dose calculation methodology were used for CyberKnife and linac‐based SBRT, respectively, to minimize respiratory impact on dose calculation. Identical image and contour sets were used for both modalities. While both modalities can provide satisfactory target dose coverage, the dose to GTV was more heterogeneous for CyberKnife than for linac planning/delivery in all cases. The dose to 1000 cc lung was well below institutional constraints for both modalities. In the high dose region, the lung dose depended on tumor size, and was similar between both modalities. In the low dose region, however, the quality of CyberKnife plans was dependent on tumor location. With anteriorly‐located tumors, the CyberKnife may deliver less dose to normal lung than linac techniques. Conversely, for posteriorly‐located tumors, CyberKnife delivery may result in higher doses to normal lung. In all cases studied, more monitor units were required for CyberKnife delivery for given prescription. Both conventional linacs and CyberKnife provide acceptable target dose coverage while sparing normal tissues. The results of this study provide a general guideline for patient and treatment modality selection based on dosimetric, tumor and normal tissue sparing considerations.PACS numbers: 87.53.Ly, 87.55.dk.

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“…[1][2][3] An active area of investigation for mitigating respiratory motion during treatment is motion tracking. 4,5 Correction of respiratory motion can be done either by repositioning the beam [6][7][8][9] or repositioning the patient. Patient repositioning methods focus on the use of dynamic couch motion to compensate for physiological motion during beam delivery.…”

Section: Introductionmentioning

confidence: 99%

“…Evaluation of all these methods involved retrospective analysis of respiratory traces including those that, like the Cyberknife Synchrony system, use a marker of internal tumor motion so that the robotically controlled Linac can follow the target. 8 In practice, implementing methods to track and correct for cyclical breathing is challenging due to sometimes rapid motion requirements, system latencies, and irregular breathing fluctuations. 20 Therefore, some investigators have proposed mean-position tracking of the respiratory motion as an alternative to full motion tracking.…”

Section: Introductionmentioning

confidence: 99%

Toward correcting drift in target position during radiotherapy via computer‐controlled couch adjustments on a programmable Linac

et al. 2013

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Purpose: Real-time tracking of respiratory target motion during radiation therapy is technically challenging, owing to rapid and possibly irregular breathing variations. The authors report on a method to predict and correct respiration-averaged drift in target position by means of couch adjustments on an accelerator equipped with such capability. Methods: Dose delivery is broken up into a sequence of 10 s field segments, each followed by a couch adjustment based on analysis of breathing motion from an external monitor as a surrogate of internal target motion. Signal averaging over three respiratory cycles yields a baseline representing target drift. A Kalman filter predicts the baseline position 5 s in advance, for determination of the couch correction. The method's feasibility is tested with a motion phantom programmed according to previously recorded patient signals. Computed couch corrections are preprogrammed into a research mode of an accelerator capable of computer-controlled couch translations synchronized with the motion phantom. The method's performance is evaluated with five cases recorded during hypofractionated treatment and five from respiration-correlated CT simulation, using a root-mean-squared deviation (RMSD) of the baseline from the treatment planned position. Results: RMSD is reduced in all 10 cases, from a mean of 4.9 mm (range 2.7-9.4 mm) before correction to 1.7 mm (range 0.7-2.3 mm) after correction. Treatment time is increased ∼5% relative to that for no corrections. Conclusions: This work illustrates the potential for reduction in baseline respiratory drift with periodic adjustments in couch position during treatment. Future treatment machine capabilities will enable the use of "on-the-fly" couch adjustments during treatment.

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Synchrony – Cyberknife Respiratory Compensation Technology

Cited by 91 publications

References 18 publications

Evaluation of tracking accuracy of the CyberKnife system using a webcam and printed calibrated grid

Evaluation of tracking accuracy of the CyberKnife system using a webcam and printed calibrated grid

A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac‐based systems

Toward correcting drift in target position during radiotherapy via computer‐controlled couch adjustments on a programmable Linac

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