The Variable Ellipsoid Modeling Technique as a Verification Method for the Treatment Planning System of Gamma Knife Radiosurgery

Hur, Beong Ik; Choi, Byung Kwan; Sung, Soon Ki; Cho, Won Ho; Heon, Seung; Choi, Chang Hwa

doi:10.3340/jkns.2010.47.2.128

Cited by 4 publications

(6 citation statements)

References 8 publications

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“…Some institutions have developed in‐house computer programs to verify the treatment shot times from the planning system for a prescribed dose 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 . These programs usually perform a point‐dose calculation based on tissue–air ratio (TAR) lookup table for narrow 60 Co beams (12) and an algorithm for patient skull geometry reconstruction 13 , 14 , 15 .…”

Section: Introductionmentioning

confidence: 99%

Two‐year experience with the commercial Gamma Knife Check software

Bhatnagar

Bednarz

et al. 2016

J Applied Clin Med Phys

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The Gamma Knife Check software is an FDA approved second check system for dose calculations in Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy and the stability of the commercial software package as a tool for independent dose verification. The Gamma Knife Check software version 8.4 was commissioned for a Leksell Gamma Knife Perfexion and a 4C unit at the University of Pittsburgh Medical Center in May 2012. Independent dose verifications were performed using this software for 319 radiosurgery cases on the Perfexion and 283 radiosurgery cases on the 4C units. The cases on each machine were divided into groups according to their diagnoses, and an averaged absolute percent dose difference for each group was calculated. The percentage dose difference for each treatment target was obtained as the relative difference between the Gamma Knife Check dose and the dose from the tissue maximum ratio algorithm (TMR 10) from the GammaPlan software version 10 at the reference point. For treatment plans with imaging skull definition, results obtained from the Gamma Knife Check software using the measurement‐based skull definition method are used for comparison. The collected dose difference data were also analyzed in terms of the distance from the treatment target to the skull, the number of treatment shots used for the target, and the gamma angles of the treatment shots. The averaged percent dose differences between the Gamma Knife Check software and the GammaPlan treatment planning system are 0.3%, 0.89%, 1.24%, 1.09%, 0.83%, 0.55%, 0.33%, and 1.49% for the trigeminal neuralgia, acoustic neuroma, arteriovenous malformation (AVM), meningioma, pituitary adenoma, glioma, functional disorders, and metastasis cases on the Perfexion unit. The corresponding averaged percent dose differences for the 4C unit are 0.33%, 1.2%, 2.78% 1.99%, 1.4%, 1.92%, 0.62%, and 1.51%, respectively. The dose difference is, in general, larger for treatment targets in the peripheral regions of the skull owing to the difference in the numerical methods used for skull shape simulation in the GammaPlan and the Gamma Knife Check software. Larger than 5% dose differences were observed on both machines for certain targets close to patient skull surface and for certain targets in the lower half of the brain on the Perfexion, especially when shots with 70 and/or 110 gamma angles are used. Out of the 1065 treatment targets studied, a 5% cutoff criterion cannot always be met for the dose differences between the studied versions of the Gamma Knife Check software and the planning system for 40 treatment targets.PACS number(s): 87.55.Qr, 87.56.Fc

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Section: Introductionmentioning

confidence: 99%

Two‐year experience with the commercial Gamma Knife Check software

Bhatnagar

Bednarz

et al. 2016

J Applied Clin Med Phys

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“…However, these studies did not addressed the calculation of the radiation depth for each gamma ray. We have developed a verification program called VEMT, a simulation program written in Java, to address this problem for the GK model C 6) .…”

Section: Discussionmentioning

confidence: 99%

Validation of Gamma Knife Perfexion Dose Profile Distribution by a Modified Variable Ellipsoid Modeling Technique

Hur

Jin

Kim

et al. 2021

J Korean Neurosurg Soc

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“…When a method is created, it would be far advantageous to obtain an algorithm with known formalism with secured agreement rate with LGP. In this regard, previous reports on verification methods are uniformly deficient due to a lack of statistical analysis9,11,13,14). Additionally, results of these studies were compared only in under certain conditions for limited parameters although many different LGP parameters are instantly available in clinical settings.…”

Section: Discussionmentioning

confidence: 99%

“…The modified variable ellipsoid modeling technique (MVEMT) was used as a verification method for our study9). For this, the patient's skull is viewed as an ellipsoid with the center at the mammillary body.…”

Section: Methodsmentioning

confidence: 99%

“…Since, this is based on a single-fraction high dose treatment strategy, independent verification of the Leksell GammaPlan® (LGP) is important for ensuring patient safety and minimizing the risk of treatment errors10,13). Previous methods for verifying LGP by various algorithms were reported by Tsai et al13), Marcu et al11), Hur et al9) and Zhang et al14).…”

Section: Introductionmentioning

confidence: 99%

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Clinical Application of Gamma Knife Dose Verification Method in Multiple Brain Tumors : Modified Variable Ellipsoid Modeling Technique

Hur

Lee

Cho

et al. 2013

J Korean Neurosurg Soc

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ObjectiveThe Leksell Gamma Knife® (LGK) is based on a single-fraction high dose treatment strategy. Therefore, independent verification of the Leksell GammaPlan® (LGP) is important for ensuring patient safety and minimizing the risk of treatment errors. Although several verification techniques have been previously developed and reported, no method has ever been tested statistically on multiple LGK target treatments. The purpose of this study was to perform and to evaluate the accuracy of a verification method (modified variable ellipsoid modeling technique, MVEMT) for multiple target treatments.MethodsA total of 500 locations in 10 consecutive patients with multiple brain tumor targets were included in this study. We compared the data from an LGP planning system and MVEMT in terms of dose at random points, maximal dose points, and target volumes. All data was analyzed by t-test and the Bland-Altman plot, which are statistical methods used to compare two different measurement techniques.ResultsNo statistical difference in dose at the 500 random points was observed between LGP and MVEMT. Differences in maximal dose ranged from -2.4% to 6.1%. An average distance of 1.6 mm between the maximal dose points was observed when comparing the two methods.ConclusionStatistical analyses demonstrated that MVEMT was in excellent agreement with LGP when planning for radiosurgery involving multiple target treatments. MVEMT is a useful, independent tool for planning multiple target treatment that provides statistically identical data to that produced by LGP. Findings from the present study indicate that MVEMT can be used as a reference dose verification system for multiple tumors.

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The Variable Ellipsoid Modeling Technique as a Verification Method for the Treatment Planning System of Gamma Knife Radiosurgery

Cited by 4 publications

References 8 publications

Two‐year experience with the commercial Gamma Knife Check software

Two‐year experience with the commercial Gamma Knife Check software

Validation of Gamma Knife Perfexion Dose Profile Distribution by a Modified Variable Ellipsoid Modeling Technique

Clinical Application of Gamma Knife Dose Verification Method in Multiple Brain Tumors : Modified Variable Ellipsoid Modeling Technique

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