Performance characterization of an integrated cone‐beam <scp>CT</scp> system for dedicated gamma radiosurgery

Sarfehnia, Arman; Ruschin, Mark; Chugh, Brige; Yeboah, Collins; Becker, Nathan; Cho, Young‐Bin; Lee, Young Kyung

doi:10.1002/mp.13073

Cited by 16 publications

(13 citation statements)

References 18 publications

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“…This work shows good agreement with previous works that showed a spatial accuracy of the IFMM to be 0.05 mm on average and within 0.16 mm maximally . A limitation of this study is that measurements were performed on a single GKI unit.…”

Section: Discussionsupporting

confidence: 91%

“…Additionally, new license guidance for use of the GKI in the United States has been released. The current license guidance from the Nuclear Regulatory Commission (NRC) for GKI dictates on a monthly basis the user will “confirm that the IFMM system is working properly by performing a test without a patient present with the aim to check the IFMM system's quantitative output.” Previous work has described commissioning a GKI system, the quality assurance, stability, and performance of the image guidance system, and described comparisons of the CBCT to IFMM; however, the full quantitative characterization of the IFMM system is absent from all of these works. We are currently unaware of any commercial systems or published literature that allow the user to quantitatively test the temporal latency along with the spatial accuracy of the IFMM system as required by the NRC and as is recommended in current published radiation oncology quality assurance guidelines …”

Section: Introductionmentioning

confidence: 99%

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Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Knutson

Hawkins²,

Bollinger

et al. 2019

J Applied Clin Med Phys

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Purpose Characterize the intra‐fraction motion management (IFMM) system found on the Gamma Knife Icon (GKI), including spatial accuracy, latency, temporal performance, and overall effect on delivered dose. Methods A phantom was constructed, consisting of a three‐axis translation mount, a remote motorized flipper, and a thermoplastic sphere surrounding a radiation detector. An infrared marker was placed on the translation mount secured to the flipper. The spatial accuracy of the IFMM was measured via the translation mount in all Cartesian planes. The detector was centered at the radiation focal point. A remote signal was used to move the marker out of the IFMM tolerance and pause the beam. A two‐channel electrometer was used to record the signals from the detector and the flipper when motion was signaled. These signals determined the latency and temporal performance of the GKI. Results The spatial accuracy of the IFMM was found to be <0.1 mm. The measured latency was <200 ms. The dose difference with five interruptions was <0.5%. Conclusion This work provides a quantitative characterization of the GKI IFMM system as required by the Nuclear Regulatory Commission. This provides a methodology for GKI users to satisfy these requirements using common laboratory equipment in lieu of a commercial solution.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Knutson

Hawkins²,

Bollinger

et al. 2019

J Applied Clin Med Phys

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“…The accuracy of the marker tracking system has been shown to be sub-0.1 mm. 6,[9][10][11] The 3-dimensional (3D) motion data are captured as a log-file together with temporal information about the treatment and CBCT acquisitions.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Infrared Motion Tracking Analysis for Patients Treated With Gated Frameless Image Guided Stereotactic Radiosurgery

MacDonald

Lee

Schasfoort³

et al. 2020

International Journal of Radiation Oncology*Biology*Physics

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The transition from frame-based brain stereotactic radiosurgery (SRS) to frameless delivery is supported by realtime intrafraction monitoring to ensure accurate delivery. The purpose of this study is to characterize these real-time motion traces in a large cohort of patients treated with frameless gated brain SRS and to develop patient-specific predictions of tolerance violations. Methods and Materials: SRS patients treated on the Gamma Knife Icon were immobilized using a device-specific thermoplastic head mask. A motion marker was fixed to the patient's nose, with gating and cone beam computed tomography (CBCT)-based corrections to the treatment at excursions from baseline exceeding 1.5 mm. The traces of 1446 fractions were analyzed according to magnitude (932 unique treatment plans for 462 unique individual patients), directional distribution of displacement, and stability. A neural network model was developed to predict interruptions based on a subset of trace data. Results: The average displacement of the marker in the first fraction of all patients was 0.62 AE 0.25 mm with beam CBCT corrections, which would otherwise be modeled at 0.96 AE 0.96 mm without intrafraction motion correction (P < .0001). Twenty-nine percent of fractions delivered were interrupted, of which the Z-axis (superoinferior) motion was the largest contributor to excursion. Baseline corrections significantly compensated for the magnitude of motion in all 3 dimensions (P < .01). The motion relative to the first acquired CBCT was on average seen to consistently increase with treatment time, with the minimum P value occurring at 61.3 minutes. The neural network prediction model was able to predict treatment interruptions with 84% sensitivity on the first 5-minute sample of the trace. Conclusions: Corrections to marker position significantly decreased marker excursions in all 3 axes compared with a single CBCT alignment. Patient-specific modeling may aid in the optimization of cases selected for frameless radiosurgery to increase the accuracy of planned delivery.

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“…When space is defined with CBCT, the other imaging sets are co‐registered with the reference CBCT for coordinate definition and then another CBCT can be acquired directly before treatment to ensure stability of coordinate system. Initial evaluations of the GK Icon and its CBCT imaging have been quite encouraging regarding the continuation of gold standard accuracy . The decision of clinical workflow with these new capabilities with the Icon depends on the comparison of the two methods of space definition regarding accuracy and efficiency.…”

Section: Introductionmentioning

confidence: 99%

Gamma Knife^® icon CBCT offers improved localization workflow for frame‐based treatment

Duggar

Morris

Fatemi

et al. 2019

J Applied Clin Med Phys

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Object: The purpose of this study was to compare two methods of stereotactic localization in Gamma Knife treatment planning: cone beam computed tomography (CBCT) or fiducial. While the fiducial method is the traditional method of localization, CBCT is now available for use with the Gamma Knife Icon. This study seeks to determine whether a difference exists between the two methods and then whether one is better than the other regarding accuracy and workflow optimization.Methods: Cone beam computed tomography was used to define stereotactic space around the Elekta Film Pinprick phantom and then treated with film in place. The same phantom was offset known amounts from center and then imaged with CBCT and registered with the reference CBCT image to determine if measured offsets matched those known. Ten frameless and 10 frame-based magnetic resonance imaging (MRI) to CBCT patient fusions were retrospectively evaluated using the TG-132 TRE method. The stereotactic coordinates defined by CBCT and traditional fiducials were compared on the Elekta 8 cm Ball phantom, an anthropomorphic phantom, and actual patient data. Offsets were introduced to the anthropomorphic phantom in the stereotactic frame and CBCT's ability to detect those offsets was determined.Results: Cone beam computed tomography defines stereotactic space well within the established limits of the mechanical alignment system. The CBCT to CBCT registration can detect offsets accurately to within 0.1 mm and 0.5°. In all cases, some disagreement existed between fiducial localization and that of CBCT which in some cases was small, but also was as high as 0.43 mm in the phantom domain and as much as 1.54 mm in actual patients. Conclusion:Cone beam computed tomography demonstrates consistent accuracy in defining stereotactic space. Since both localization methods do not agree with each other consistently, the more reliable method must be identified. Cone beam computed tomography can accurately determine offsets occurring within stereotactic space that would be nondiscernible utilizing the fiducial method and seems to be more reliable. Using CBCT localization offers the opportunity to streamline workflow

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Performance characterization of an integrated cone‐beam CT system for dedicated gamma radiosurgery

Abstract: A set of system performance characterization tests spanning all aspects of the Gamma Knife Icon are presented. Overall, the system performance was in line with manufacturer specifications.

Cited by 16 publications

References 18 publications

Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Real-Time Infrared Motion Tracking Analysis for Patients Treated With Gated Frameless Image Guided Stereotactic Radiosurgery

Gamma Knife^® icon CBCT offers improved localization workflow for frame‐based treatment

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Performance characterization of an integrated cone‐beam CT system for dedicated gamma radiosurgery

Abstract: A set of system performance characterization tests spanning all aspects of the Gamma Knife Icon are presented. Overall, the system performance was in line with manufacturer specifications.

Cited by 16 publications

References 18 publications

Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Characterization and validation of an intra‐fraction motion management system for masked‐based radiosurgery

Real-Time Infrared Motion Tracking Analysis for Patients Treated With Gated Frameless Image Guided Stereotactic Radiosurgery

Gamma Knife® icon CBCT offers improved localization workflow for frame‐based treatment

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Product

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Gamma Knife^® icon CBCT offers improved localization workflow for frame‐based treatment