PRIMO Monte Carlo software benchmarked against a reference dosimetry dataset for 6 MV photon beams from Varian linacs

Hermida-López, M.; Sánchez-Artuñedo, D.; Calvo-Ortega, J.F.

doi:10.1186/s13014-018-1076-0

Cited by 11 publications

(27 citation statements)

References 20 publications

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“…The average point-by-point differences between measured and calculated PDDs were < 1% for fields ≥3 × 3 cm 2 . This result is in line with the one obtained by Hermida-López et al [1] where the agreement between dose simulated with PRIMO and measurements was within 1.3%. Dose profiles showed average point-by-point differences below 2% for all considered field sizes.…”

Section: Resultssupporting

confidence: 93%

“…Monte Carlo (MC) method is widely acknowledged to be able to estimate accurate dose distributions from radiotherapy beams generated by clinical linacs, and has been approached and used in radiotherapy during the last decades [1]. However, the need of long computation times has been a major obstacle to the use of MC in the clinical practice.…”

Section: Introductionmentioning

confidence: 99%

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MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

et al. 2019

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BackgroundPRIMO is a graphical environment based on PENELOPE Monte Carlo (MC) simulation of radiotherapy beams able to compute dose distribution in patients, from plans with different techniques. The dosimetric characteristics of an HD-120 MLC (Varian), simulated using PRIMO, were here compared with measurements, and also with Acuros calculations (in the Eclipse treatment planning system, Varian).Materials and methodsA 10 MV FFF beam from a Varian EDGE linac equipped with the HD-120 MLC was used for this work. Initially, the linac head was simulated inside PRIMO, and validated against measurements in a water phantom. Then, a series of different MLC patterns were established to assess the MLC dosimetric characteristics. Those tests included: i) static fields: output factors from MLC shaped fields (2 × 2 to 10 × 10 cm2), alternate open and closed leaf pattern, MLC transmitted dose; ii) dynamic fields: dosimetric leaf gap (DLG) evaluated with sweeping gaps, tongue and groove (TG) effect assessed with profiles across alternate open and closed leaves moving across the field. The doses in the different tests were simulated in PRIMO and then compared with EBT3 film measurements in solid water phantom, as well as with Acuros calculations. Finally, MC in PRIMO and Acuros were compared in some clinical cases, summarizing the clinical complexity in view of a possible use of PRIMO as an independent dose calculation check.ResultsStatic output factor MLC tests showed an agreement between MC calculated and measured OF of 0.5%. The dynamic tests presented DLG values of 0.033 ± 0.003 cm and 0.032 ± 0.006 cm for MC and measurements, respectively. Regarding the TG tests, a general agreement between the dose distributions of 1–2% was achieved, except for the extreme patterns (very small gaps/field sizes and high TG effect) were the agreement was about 4–5%. The analysis of the clinical cases, the Gamma agreement between MC in PRIMO and Acuros dose calculation in Eclipse was of 99.5 ± 0.2% for 3%/2 mm criteria of dose difference/distance to agreement.ConclusionsMC simulations in the PRIMO environment were in agreement with measurements for the HD-120 MLC in a 10 MV FFF beam from a Varian EDGE linac. This result allowed to consistently compare clinical cases, showing the possible use of PRIMO as an independent dose calculation check tool.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

et al. 2019

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“…The effect on the calculated absolute dose for very small fields (≤1 × 1 cm 2 ) and shape of the calculated penumbra is yet unclear and will be investigated in the near future. Dedicated MC models like PRIMO and BEAMnrc show excellent agreement between measurement and model prediction but typically down to field sizes of 3 × 3 cm 2 36,37 . A full MC simulation for fields sizes below 3 × 3 cm 2 was, however, beyond the scope of our work.…”

Section: Discussionmentioning

confidence: 90%

“…Dedicated MC models like PRIMO and BEAMnrc show excellent agreement between measurement and model prediction but typically down to field sizes of 3 9 3 cm 2 . 36,37 A full MC simulation for fields sizes below 3 9 3 cm 2 was, however, beyond the scope of our work.…”

Section: Discussionmentioning

confidence: 99%

Acuros^® dose verification of ultrasmall lung lesions with EBT‐XD film in a homogeneous and heterogeneous anthropomorphic phantom setup

2020

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Purpose Modern type ‘c’ dose calculation algorithms like Acuros® can predict dose for lung tumors larger than approximately 4 cm3 with a relative uncertainty up to 5%. However, increasingly better tumor diagnostics are leading to the detection of very small early‐stage lung tumors that can be treated with stereotactic body radiotherapy (SBRT) for inoperable patients. This raises the question whether dose algorithms like Acuros® can still accurately predict dose within 5% for challenging conditions involving small treatment fields. Current recommendations for Quality Assurance (QA) and dose verification in SBRT treatments are to use phantoms that are as realistic as possible to the clinical situation, although water‐equivalent phantoms are still largely used for dose verification. In this work we aim to demonstrate that existing dose verification methods are inadequate for accurate dose verification in very small lung tumors treated with SBRT. Method The homogeneous PTW Octavius4D phantom with the Octavius 1000 SRS detector (“Octavius4D phantom”) and the heterogeneous CIRS Dynamic Thorax phantom (‘CIRS phantom’) were used for dose measurements. The CIRS phantom contained different lung‐equivalent film‐holding cylindrical phantom inserts (“film inserts”) with water‐equivalent spherical targets with diameters 0.5, 0.75, 1, 2, and 3 cm. Plans were calculated for 6 and 10 MV for each spherical target in the CIRS phantom, resulting in 14 treatment plans. The plans were delivered to both Octavius4D and CIRS phantom to compare measured dose in a commonly used homogeneous and more realistic heterogeneous phantom setup. In addition, treatment plans of seven clinical lung cancer patients with lung tumors below approximately 1.0 cm3 were irradiated in the heterogeneous CIRS phantom. The actual tumor size within the clinical treatment plans determined the choice of the spherical target size, such that both measurement geometry and clinical target volumes match as closely as possible. The Acuros® dose algorithm (version 15.5.11) was used for all dose calculations reporting dose‐to‐medium using a 0.1‐cm‐grid size. Results The measurement discrepancies in the homogeneous Octavius4D phantom for the fourteen treatment plans were within 1.5%. Dose discrepancies between measurement and treatment planning systems (TPS) for the heterogeneous CIRS phantom increased for both 6 and 10 MV with decreasing target diameters up to 23.7 ± 1.0% for 6 MV and 8.8 ± 1.1% for 10 MV for the smallest target of 0.5 cm in diameter with a 2‐mm‐CTV‐PTV margin. For the seven clinical plans this trend of increasing dose difference with decreasing tumor size is less pronounced although the smallest tumors show the largest differences between measurement and TPS up to 16.6 ± 0.9%. Conclusion Current verification methods using homogenous phantoms are not adequate for lung tumors with diameters below approximately 0.75 cm. The current Acuros® dose calculation algorithm underestimates dose in very small lung tumors. Dose verification of small lung tumors should...

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“…A dosimetric accuracy within 2.8% was found for 6 MV beams from the Varian Clinac 2100 CD with a Millennium 120 MLC used in the present study. 29 Our team also validated PRIMO to be used for independent verification of IMRT SRS plans. 30 SRS plans for single and multiple targets defined in a polystyrene phantom were simulated with PRIMO and dose planes were compared against radiochromic film measurements.…”

Section: C | Verification Of the Viper 3d Dose Reconstructionmentioning

confidence: 99%

Validation of virtual water phantom software for pre‐treatment verification of single‐isocenter multiple‐target stereotactic radiosurgery

Calvo-Ortega

Greer

Hermida-López

et al. 2021

J Applied Clin Med Phys

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The aim of this study was to benchmark the accuracy of the VIrtual Phantom Epid dose Reconstruction (VIPER) software for pre-treatment dosimetric verification of multiple-target stereotactic radiosurgery (SRS). VIPER is an EPID-based method to reconstruct a 3D dose distribution in a virtual phantom from in-air portal images. Validation of the VIPER dose calculation was assessed using several MLC-defined fields for a 6 MV photon beam. Central axis percent depth doses (PDDs) and output factors were measured with an ionization chamber in a water tank, while dose planes at a depth of 10 cm in a solid flat phantom were acquired with radiochromic films. The accuracy of VIPER for multiple-target SRS plan verification was benchmarked against Monte Carlo simulations. Eighteen multiple-target SRS plans designed with the Eclipse treatment planning system were mapped to a cylindrical water phantom. For each plan, the 3D dose distribution reconstructed by VIPER within the phantom was compared with the Monte Carlo simulation, using a 3D gamma analysis. Dose differences (VIPER vs. measurements) generally within 2% were found for the MLC-defined fields, while film dosimetry revealed gamma passing rates (GPRs) ≥95% for a 3%/1 mm criteria. For the 18 multiple-target SRS plans, average 3D GPRs greater than 93% and 98% for the 3%/2 mm and 5%/2 mm criteria, respectively. Our results validate the use of VIPER as a dosimetric verification tool for pre-treatment QA of single-isocenter multiple-target SRS plans. The method requires no setup time on the linac and results in an accurate 3D characterization of the delivered dose.

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PRIMO Monte Carlo software benchmarked against a reference dosimetry dataset for 6 MV photon beams from Varian linacs

Cited by 11 publications

References 20 publications

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

Acuros^® dose verification of ultrasmall lung lesions with EBT‐XD film in a homogeneous and heterogeneous anthropomorphic phantom setup

Validation of virtual water phantom software for pre‐treatment verification of single‐isocenter multiple‐target stereotactic radiosurgery

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PRIMO Monte Carlo software benchmarked against a reference dosimetry dataset for 6 MV photon beams from Varian linacs

Cited by 11 publications

References 20 publications

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

Acuros® dose verification of ultrasmall lung lesions with EBT‐XD film in a homogeneous and heterogeneous anthropomorphic phantom setup

Validation of virtual water phantom software for pre‐treatment verification of single‐isocenter multiple‐target stereotactic radiosurgery

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Acuros^® dose verification of ultrasmall lung lesions with EBT‐XD film in a homogeneous and heterogeneous anthropomorphic phantom setup