Feasibility Study of Mobius3D for Patient-Specific Quality Assurance in the Volumetric Modulated Arc Therapy

Lee, Chang Yeol; Kim, Woo Chul; Kim, Hun Jeong; Lee, Jeongshim; Huh, Hyun Do

doi:10.14316/pmp.2019.30.4.120

Cited by 5 publications

(11 citation statements)

References 16 publications

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“…The result of portal dosimetry (3%/3 mm) used in patientspecific QA was statistically similar to the paired t-test of the QA result of MobiusFX (5%/3 mm). In previous studies, IMRT and VMAT were verified using EPIDs and gamma analysis for patient-specific QA [23][24][25][26]28,29]. Mobius3D provides a second-check dosimetry system for the verification of the radiation treatment plan using a collapsed CC algorithm, besides the primary TPS.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, Lee et al [24] evaluated the dosimetric performance of Mobius3D by comparing this system with EPID and Octavius 4D, which are conventionally used for patient-specific prescription dose verification, in nine patients treated using VMAT. The authors showed the percentage differences between the calculated point dose and the measurements in a PTW31010 ionization chamber.…”

Section: Resultsmentioning

confidence: 99%

“…This system is a novel commercial log file-based online system that provides a comprehensive patient-specific QA program. Planning and delivery are verified using an independent three-dimensional dose calculation algorithm and treatment log files [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have evaluated the characteristics of Mobius3D and reported the related commissioning results. However, a limited number of clinical performance evaluations of this system have been performed [23][24][25][26]. To overcome this shortfall, our study used data from many patients (n=122) to confirm that this independent second-check dosimetry system can be clinically used in both VitalBeam (Varian Medical System) and Novalis Tx linear accelerators (Varian Medical System).…”

Section: Introductionmentioning

confidence: 99%

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A Comparison between Portal Dosimetry and Mobius3D Results for Patient-Specific Quality Assurance in Radiotherapy

Kim

Park

et al. 2021

Progress in Medical Physics

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The purpose of this study was to compare the clinical quality assurance results of portal dosimetry using an electronic portal imaging device, a method that is extensively used for patientspecific quality assurance, and the newly released Mobius3D for intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT).Methods: This retrospective study includes data from 122 patients who underwent IMRT and VMAT on the Novalis Tx and VitalBeam linear accelerators between April and June 2020. We used a paired t-test to compare portal dosimetry using an electronic portal imaging device and the average gamma passing rates of MobiusFX using log files regenerated after patient treatment. Results:The average gamma passing rates of portal dosimetry (3%/3 mm) and MobiusFX (5%/3 mm) were 99.43%±1.02% and 99.32%±1.87% in VitalBeam and 97.53%±3.34% and 96.45%±13.94% in Novalis Tx, respectively. Comparison of the gamma passing rate results of portal dosimetry (3%/3 mm) and MobiusFX (5%/3 mm as per the manufacturer's manual) does not show any statistically significant difference.Conclusions: Log file-based patient-specific quality assurance, including independent dose calculation, can be appropriately used in clinical practice as a second-check dosimetry, and it is considered comparable with primary quality assurance such as portal dosimetry.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Comparison between Portal Dosimetry and Mobius3D Results for Patient-Specific Quality Assurance in Radiotherapy

Kim

Park

et al. 2021

Progress in Medical Physics

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“…The study found a small difference in the point dose measurement between the ion chamber and other dose calculation algorithms like AAA, CCCS, and AcurosXB. The percentage mean dose difference between M3D and EPID was only 0.46% 18 . Similarly, Basavatia et al., compared MFX with conventional QA methods and determined that 3%/3 mm was an appropriate gamma criterion for PSQA when utilizing MFX 8 .…”

Section: Discussionmentioning

confidence: 99%

Commissioning of Mobius3D/FX for patient‐specific quality assurance: The CUIMC—NewYork Presbyterian Hospital experience

Li,

Price

2023

J Applied Clin Med Phys

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PurposeTo present the process undertaken by our institute in commissioning Mobius3D (M3D) for patient‐specific quality assurance.Method168 plans were randomly selected to compare dose distribution measured with ArcCheck and dose calculated from M3D, both compared against the treatment planning system (TPS). The gamma criteria for measurement and M3D are 3%/2 mm with 10% and 50% dose thresholds, respectively. The effect of tissue inhomogeneity was investigated on 11 plans by recalculating the dose in M3D on a homogeneous phantom. Tolerance and action limits were established following the AAPM Task Group 218 recommendations.ResultsThe M3D showed high variability in gamma passing rate compared to the measurement. Twenty‐three out of 168 plans had false negative dose comparisons. These plans fall under high tissue inhomogeneity like lung and metal implants, small field targets, and breast plans planned with high energy. One false negative case (0.6%) was observed. A single tolerance limit of 91% and 92% gamma passing rate for the M3D and measurement‐based PSQA were established, respectively. Against the expectation, recalculating plans on the homogeneous phantom in M3D did not necessarily increase the gamma passing rate. These plans have a duty cycle >4.2, and the small field sizes combined with differences in slice thickness contributed to observed dose differences in the homogeneous phantom comparisons.ConclusionFollowing the commissioning, M3D is adopted in our institute. Currently, the gamma criteria used for measurement and M3D are 3%/2 mm, 40% dose threshold, with gamma passing rates of 92% and 95%, respectively. A higher passing rate for M3D is adopted until more data is available. The combined effect of plan modulation, the field sizes, the tissue inhomogeneity, the dose algorithm, and the volume averaging effect from differences in slice thickness can contribute to the differences in dose in M3D and TPS.

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Clinical implementation of PerFRACTION™ for pre-treatment patient-specific quality assurance

Kang

Lee

Song

et al. 2022

J. Korean Phys. Soc.

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Feasibility Study of Mobius3D for Patient-Specific Quality Assurance in the Volumetric Modulated Arc Therapy

Cited by 5 publications

References 16 publications

A Comparison between Portal Dosimetry and Mobius3D Results for Patient-Specific Quality Assurance in Radiotherapy

A Comparison between Portal Dosimetry and Mobius3D Results for Patient-Specific Quality Assurance in Radiotherapy

Commissioning of Mobius3D/FX for patient‐specific quality assurance: The CUIMC—NewYork Presbyterian Hospital experience

Clinical implementation of PerFRACTION™ for pre-treatment patient-specific quality assurance

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