Ep-1440 Dosimetry Comparison of Vmat Dose Delivery Capability of Beam Matched Linear Accelerators in Multi Site Environment

Swamy, Shivakumar; Subramanian, V.; Kumar, S.A. Syam; Garg, Arun; Kathirvel, M; Ramalingam, K.; Mallik, Suman

doi:10.1016/s0167-8140(12)71773-5

Cited by 2 publications

(7 citation statements)

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“…In the literature, the quality or accuracy of beam matching has been assessed by the standard deviation in gamma pass rates for a particular treatment, with standard deviations around 1% constituting excellent agreement. Accordingly, this study has shown that the linacs considered are also well matched in parameters (output factors, depth‐dose curves, profiles, energy and dose rate, MLC positional accuracy, MLC speed, jaw positional accuracy, gantry speed etc …”

Section: Discussionmentioning

confidence: 81%

“…demonstrated that a single TPS model could not be supported by their three Elekta linacs which were matched according to the vendor's beam matching criteria, calling for stricter criteria and an additional subset of dosimetric data to be matched to if a single model was to be used. Alternatively, a study by Swamy et al., like Sjöström et al., also considered “fine beam‐matched” Varian linacs and found that from delivery of fifteen volumetric modulated arc therapy (VMAT) plans, the standard deviation in gamma (2%/2 mm) pass rates was 1.00%, demonstrating excellent beam matching in terms of VMAT delivery . To date there have not been any studies published considering beam matching for stereotactic body radiotherapy (SBRT) and the tighter tolerances and objectives it might require, so the feasibility of distributive QA and treatment delivery of SBRT should thus be assessed and verified.…”

Section: Introductionmentioning

confidence: 99%

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Distributive quality assurance and delivery of stereotactic ablative radiotherapy treatments amongst beam matched linear accelerators: A feasibility study

Rijken

Schachenmayr²,

Crowe

et al. 2019

J Applied Clin Med Phys

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Purpose Beam matching occurs on all linacs to some degree and when two are more are matched to each other, patients are able to be transferred between machines. Quality assurance of plans can also be performed “distributively” on any of the matched linacs. The degree to which machines are matched and how this translates to like delivery of plans has been the focus of a number of studies. This concept has not yet been explored for stereotactic techniques which require a higher degree of accuracy. This study proposes beam matching criteria which allows for the distributive delivery and quality assurance of stereotactic body radiotherapy (SBRT) plans. Method Two clinically relevant and complex volumetric modulated arc therapy (VMAT) SBRT spine and lung plans were chosen as benchmarking cases. These were delivered on nine previously beam matched linacs with quality assurance performed through ArcCheck and film exposure in the sagittal plane. Measured doses were compared to their treatment planning system predictions through gamma analysis at a range of criteria. Results Despite differences in beam match parameters and variations in small fields, all nine linacs produced accurate deliveries with a tight deviation in the population sample. Pass rates were well above suggested tolerances at the recommended gamma criterion. Film was able to detect dose errors to a greater degree than ArcCheck. Conclusion Distributive quality assurance and delivery of stereotactic ablative radiotherapy treatments amongst beam matched linacs is certainly feasible provided the linacs are matched to a strict protocol like that suggested in this study and regular quality assurance is performed on the matched fleet. Distributive quality assurance and delivery of SBRT provides the possibility of efficiency gains for physicists as well as treatment staff.

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Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Distributive quality assurance and delivery of stereotactic ablative radiotherapy treatments amongst beam matched linear accelerators: A feasibility study

Rijken

Schachenmayr²,

Crowe

et al. 2019

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…The ability to match linacs at a level sufficient for routine treatments and PSQA has been assessed in several studies 1–8 . Initial investigations focus on the ability to achieve a high level of matching between characteristics of the linac output, such as beam profiles, depth dose curves, and output factors 1,2,4 .…”

Section: Introductionmentioning

confidence: 99%

“…The ability to match linacs at a level sufficient for routine treatments and PSQA has been assessed in several studies. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 Initial investigations focus on the ability to achieve a high level of matching between characteristics of the linac output, such as beam profiles, depth dose curves, and output factors. 1 , 2 , 4 Further investigations consider the resultant similarity within composite dose deliveries for volumetric‐modulated arc therapy (VMAT) or intensity‐modulated radiotherapy (IMRT).…”

Section: Introductionmentioning

confidence: 99%

“… 1 , 2 , 4 Further investigations consider the resultant similarity within composite dose deliveries for volumetric‐modulated arc therapy (VMAT) or intensity‐modulated radiotherapy (IMRT). 3 , 5 , 8 More recently investigations have begun to consider the possibility of linac matching at the level required for stereotactic radiotherapy. 6 , 7 …”

Section: Introductionmentioning

confidence: 99%

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Matched linac stereotactic radiotherapy: An assessment of delivery similarity and distributive patient‐specific quality assurance feasibility

Goodall

Dunn

Dunning

et al. 2022

J Applied Clin Med Phys

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Matching multiple linacs to common baseline data allows patients to be treated, and patient‐specific quality assurance (PSQA) to be completed on any linac. Stereotactic body radiotherapy (SBRT) requires higher levels of accuracy and quality assurance than routine radiotherapy. The achieved linac matching must therefore be evaluated before distributive treatment or PSQA models can be implemented safely. This investigation aimed to propose metrics for defining linacs to be matched for SBRT deliveries, assess 12 linacs against these criteria, and determine if a distributive PSQA model could be implemented by reviewing the rates of false PSQA results. Ten SBRT spine plans were delivered by 12 matched Elekta linacs and measured using one of seven SRS MapCHECK devices. For gamma criteria of (3%, 2 mm), 96.9% of equivalent location detectors, showed a range of gamma ≤ 1.0 and 99.9% showed a standard deviation of ≤ 0.5. For criteria of (3%,1 mm) and (2%,1 mm), these ranges decreased to 92.1% and 80.2% while the standard deviations decreased to 99.3% and 95.7%, respectively. The dose differences showed that 43.6%, 82.7%, and 91.4% of detectors had a dose range of ≤ 3.0%, ≤ 5.0%, and ≤ 6.0%, respectively. Standard deviations of dose differences were 1.5%, 2.5%, and 3.0% for 94.1%, 98.3%, and 99.5% of detectors, respectively. For the fleet of linacs, distributive PSQA yielded false results for 0.0%, 17.7%, and 33.0% of plans, equivalent to 1.2%, 3.5%, and 9.4% of detectors when using gamma criteria of (3%,2 mm), (3%,1 mm), or (2%,1 mm), respectively. These linacs could be considered matched for SBRT treatments and implement a distributive PSQA model when gamma analysis was completed with a criterion of (3%, 2 mm). For stricter criterion of (3%,1 mm) or (2%,1 mm), they did not meet the proposed metrics.

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Ep-1440 Dosimetry Comparison of Vmat Dose Delivery Capability of Beam Matched Linear Accelerators in Multi Site Environment

Cited by 2 publications

References 0 publications

Distributive quality assurance and delivery of stereotactic ablative radiotherapy treatments amongst beam matched linear accelerators: A feasibility study

Distributive quality assurance and delivery of stereotactic ablative radiotherapy treatments amongst beam matched linear accelerators: A feasibility study

Matched linac stereotactic radiotherapy: An assessment of delivery similarity and distributive patient‐specific quality assurance feasibility

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