Use of a plastic scintillator detector for patient‐specific quality assurance of VMAT SRS

Snyder, Jesse D.; Sullivan, Rodney J.; Wu, X; Covington, Elizabeth; Popple, Richard A.

doi:10.1002/acm2.12705

Cited by 7 publications

(5 citation statements)

References 16 publications

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“…RCF agreed well with a plastic scintillator detector, 22 so the systematic 1.2% difference between the SRSMC and RCF suggests a difference in response of the diode array due to the non‐coplanar VMAT delivery of patient plans and the coplanar calibration geometry. Further investigation is needed to determine if this difference is consistent across multiple diode arrays and if an improved calibration technique can be developed to reduce the difference.…”

Section: Discussionmentioning

confidence: 65%

Evaluation of a two‐dimensional diode array for patient‐specific quality assurance of HyperArc

Popple

Sullivan

Yuan

et al. 2021

J Applied Clin Med Phys

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To evaluate a two-dimensional diode array for patient-specific quality assurance of VMAT stereotactic radiosurgery (SRS) plans. Methods: The diode array, an SRS MapCHECK (SRSMC), was composed of a 77 mm ×77 mm face-centered array having a spacing of 2.47 mm. Sixty SRS plans were selected from our clinical database, 30 for treatment of a single target and 30 for multiple targets. The target sizes ranged from 2.4 mm to 44.7 mm equivalent diameter (median 8.7 mm). The plans were delivered to the diode array. For multiple target plans, two measurements were obtained at two locations,one corresponding to the largest target and the other to the smallest target. Gamma using a 3%/1 mm criteria and the dose to the center diode were compared with radiochromic film (RCF). Dose to selected regions of the detector electronics was calculated. Results:The mean difference between the center diode and RCF was −1.2%. For a threshold of at least 95% of detectors/pixels having gamma < 1 for a 3%/1 mm criteria, SRSMC and RCF gave consistent results for 79 of the 90 measurements. For plans with an arc having a patient support angle of 90 • or 270 • , the median dose to the electronics was 0.65% of the prescription dose. Conclusions: SRSMC is an efficient tool for accurate patient-specific quality assurance of VMAT single and multiple target radiosurgery, yielding similar clinical decisions as radiochromic film.

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Section: Discussionmentioning

confidence: 65%

Evaluation of a two‐dimensional diode array for patient‐specific quality assurance of HyperArc

Popple

Sullivan

Yuan

et al. 2021

J Applied Clin Med Phys

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“…Our results are comparable with these studies for similar measurement positions. To improve the dose measurement, a study by Snyder and Sullivan 34 suggested calibrating the plastic scintillator dosimeter with a 4 × 4 cm 2 field size for the VMAT dose measurement. This is because the techniques are delivered in smaller segments and calibrating at smaller field size match closer to the irradiation condition.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of determining external beam radiotherapy dose using LuSy dosimeter

Wahabi,

Wong,

Mahdiraji

et al. 2024

J Applied Clin Med Phys

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IntroductionRadiation dose measurement is an essential part of radiotherapy to verify the correct delivery of doses to patients and ensure patient safety. Recent advancements in radiotherapy technology have highlighted the need for fast and precise dosimeters. Technologies like FLASH radiotherapy and magnetic‐resonance linear accelerators (MR‐LINAC) demand dosimeters that can meet their unique requirements. One promising solution is the plastic scintillator‐based dosimeter with high spatial resolution and real‐time dose output. This study explores the feasibility of using the LuSy dosimeter, an in‐house developed plastic scintillator dosimeter for dose verification across various radiotherapy techniques, including conformal radiotherapy (CRT), intensity‐modulated radiation therapy (IMRT), volumetric‐modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS).Materials and methodsA new dosimetry system, comprising a new plastic scintillator as the sensing material, was developed and characterized for radiotherapy beams. Treatment plans were created for conformal radiotherapy, IMRT, VMAT, and SRS and delivered to a phantom. LuSy dosimeter was used to measure the delivered dose for each plan on the surface of the phantom and inside the target volumes. Then, LuSy measurements were compared against an ionization chamber, MOSFET dosimeter, radiochromic films, and dose calculated using the treatment planning system (TPS).ResultsFor CRT, surface dose measurement by LuSy dosimeter showed a deviation of ‐5.5% and ‐5.4% for breast and abdomen treatment from the TPS, respectively. When measuring inside the target volume for IMRT, VMAT, and SRS, the LuSy dosimeter produced a mean deviation of ‐3.0% from the TPS. Surface dose measurement resulted in higher TPS discrepancies where the deviations for IMRT, VMAT, and SRS were ‐2.0%, ‐19.5%, and 16.1%, respectively.ConclusionThe LuSy dosimeter was feasible for measuring radiotherapy doses for various treatment techniques. Treatment delivery verification enables early error detection, allowing for safe treatment delivery for radiotherapy patients.

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“…A plastic scintillator detector needs to be calibrated before absolute dose measurement due to the Cerenkov effect, which is field-size dependent. According to the research of Snyder et al , 14 the authors found a low sensitivity to the Cerenkov factor under different sizes of calibration fields, but the residual deviations suggested that the calibration should be done under a condition similar to which the measurements will be made in. Therefore, a 10 × 10 cm 2 field was used for IMRT plan verification, and a 4 × 4 cm 2 field was used for VMAT SRS plan verification in this study.…”

Section: Discussionmentioning

confidence: 99%

“…For determining the known dose, a Farmer-Type chamber Exradin A19 was used. According to the literature, 14 W1 was calibrated using a 6MV FFF beam and a 4 × 4 cm 2 field for VMAT SRS plans whereas a 6MV beam and a 10 × 10 cm 2 field were used for IMRT plans. Since PSD has a slight temperature dependency, all experiments were carried out at a constant temperature of 22°C with the variation being less than 1°C, so that the temperature dependency was irrelevant.…”

Section: Methodsmentioning

confidence: 99%

Quality Assurance for Small-Field VMAT SRS and Conventional-Field IMRT Using the Exradin W1 Scintillator

Huang

Qiao

Yang

et al. 2021

Technol Cancer Res Treat

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Background: Plastic scintillator detector (PSD) Exradin W1 has shown promising performance in small field dosimetry due to its water equivalence and small sensitive volume. However, few studies reported its capability in measuring fields of conventional sizes. Therefore, the purpose of this study is to assess the performance of W1 in measuring point dose of both conventional IMRT plans and VMAT SRS plans. Methods: Forty-seven clinical plans (including 29 IMRT plans and 18 VMAT SRS plans with PTV volume less than 8 cm3) from our hospital were included in this study. W1 and Farmer-Type ionization chamber Exradin A19 were used in measuring IMRT plans, and W1 and microchamber Exradin A16 were used in measuring SRS plans. The agreement between the results of different types of detectors and TPS was evaluated. Results: For IMRT plans, the average differences between measurements and TPS in high-dose regions were 0.27% ± 1.66% and 0.90% ± 1.78% ( P = 0.056), and were −0.76% ± 1.47% and 0.37% ± 1.34% in low-dose regions ( P = 0.000), for W1 and A19, respectively. For VMAT SRS plans, the average differences between measurements and TPS were −0.19% ± 0.96% and −0.59% ± 1.49% for W1 and A16 with no statistical difference ( P = 0.231). Conclusion: W1 showed comparable performance with application-dedicated detectors in point dose measurements for both conventional IMRT and VMAT SRS techniques. It is a potential one-stop solution for general radiotherapy platforms that deliver both IMRT and SRS plans.

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Use of a plastic scintillator detector for patient‐specific quality assurance of VMAT SRS

Cited by 7 publications

References 16 publications

Evaluation of a two‐dimensional diode array for patient‐specific quality assurance of HyperArc

Evaluation of a two‐dimensional diode array for patient‐specific quality assurance of HyperArc

Feasibility of determining external beam radiotherapy dose using LuSy dosimeter

Quality Assurance for Small-Field VMAT SRS and Conventional-Field IMRT Using the Exradin W1 Scintillator

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