A dosimetric evaluation of the Eclipse AAA algorithm and Millennium 120 MLC for cranial intensity-modulated radiosurgery

Ortega, J.F. Calvo; Moragues, Sandra; Pozo, Miquel; José, Sol San; Puertas, Enrique; Gómez, Jaime; Casals, Joan

doi:10.1016/j.meddos.2013.11.003

Cited by 8 publications

(2 citation statements)

References 19 publications

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“…Therefore, although SRS delivery accuracy is aimed for < 1 mm, we have chosen a DTA of 2 mm to take into account the EPID positional error. In the context of PTV margins used for treatment, Bossuyt et al described the use of the CTV-PTV margin as DTA for transit in-vivo PSQA based on EPID measurements [ 33 ]. The 2 mm-DTA used in the present study coincides with the CTV-PTV margin implemented in our SIMT SRS policy [ 29 ].…”

Section: Methodsmentioning

confidence: 99%

Verification of stereotactic radiosurgery plans for multiple brain metastases using a virtual phantom-based procedure

Calvo-Ortega

Greer

Moragues-Femenía

et al. 2022

Rep Pract Oncol Radiother.

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Background:The purpose of this study was to describe the use of the VIPER software for patient-specific quality assurance (PSQA) of single-isocenter multitarget (SIMT) stereotactic radiosurgery (SRS) plans. Materials and methods:Twenty clinical of intensity-modulated (IMRT) SIMT SRS plans were reviewed. A total of 88 brain metastases were included. Number of lesions per plan and their individual volumes ranged from 2 to 35 and from 0.03 to 32.8 cm 3 , respectively. Plans were designed with the Eclipse system, and delivered using a Varian CLINAC linac. SRS technique consisted of non-coplanar static-field sliding-window IMRT.Each plan was mapped onto a virtual cylindrical water phantom (VCP) in the Eclipse to calculate a 3D dose distribution (verification plan). The VIPER software reconstructed the 3D dose distribution inside the VCP from the acquired in-air electronic portal image device (EPID) images of the treatment fields.A 3D gamma analysis was used to compare the reconstructed doses to the Eclipse planned doses on the VCP. Gamma passing rates (GPRs) were calculated using 3% global/2 mm criteria and dose thresholds ranged from 10% to 90% of the maximum dose. Results:The averages (± 1 SD) of the 3D GPRs over the 20 SRS plans were: 99.9 ± 0.2%, 99.7 ± 0.3%, 99.6 ± 0.5%, 99.3 ± 0.9%,99.1 ± 1.6%, 99.0 ± 1.6%, and 98.5 ± 3.3%, for dose thresholds of 10%, 20%, 30%, 50%, 70%, 80% and 90% respectively. Conclusions:This work shows the feasibility of the VIPER software for PSQA of SIMT SRS plans, being a reliable alternative to commercially available 2D detector arrays.

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Section: Methodsmentioning

confidence: 99%

Verification of stereotactic radiosurgery plans for multiple brain metastases using a virtual phantom-based procedure

Calvo-Ortega

Greer

Moragues-Femenía

et al. 2022

Rep Pract Oncol Radiother.

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“…This results in a pixel size of 0.784 mm when it is placed at a source‐detector‐distance (SDD) of 100 cm. The accuracy of the dose calculation performed by Eclipse for small lesions, and the targeting accuracy of single‐isocenter IMRT SRS for multiple lesions were previously investigated by our group 22,23 …”

Section: Methodsmentioning

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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Investigating the spatial accuracy of CBCT-guided cranial radiosurgery: A phantom end-to-end test study

et al. 2017

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A dosimetric evaluation of the Eclipse AAA algorithm and Millennium 120 MLC for cranial intensity-modulated radiosurgery

Cited by 8 publications

References 19 publications

Verification of stereotactic radiosurgery plans for multiple brain metastases using a virtual phantom-based procedure

Verification of stereotactic radiosurgery plans for multiple brain metastases using a virtual phantom-based procedure

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

Investigating the spatial accuracy of CBCT-guided cranial radiosurgery: A phantom end-to-end test study

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