Dosimetric impact of switching from AAA to Acuros dose-to-water and dose-to-medium for RapidArc plans of nasopharyngeal carcinomas

Sayah, R.; Felefly, Tony; Zouein, L.; Barouky, J.; Khater, N.; Farah, N.; Roukoz, C.; Khoury, C. El; Azoury, F.; Nasr, D. Nehme; Nasr, Elie

doi:10.1016/j.canrad.2020.05.014

Cited by 7 publications

(18 citation statements)

References 27 publications

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“…A number of studies closely examined the effects of using Type C dose algorithms in the HN plans 9–20,40 . The common thread among the findings is reduced dose to bone, when dose‐to‐tissue is reported, compared to the Type A or B algorithms.…”

Section: Discussionmentioning

confidence: 99%

“…The dose differences were particularly large in bone, 15,18 although some authors also noted differences in air 9 . The primary target dose heterogeneity often evaluated as D 2% / D 98% in the target was typically higher for the Type C algorithms 11,13,17,18 . However, the comparisons were, as rule, done between the same plans calculated consecutively with the Type B and C algorithms, 13,17,18 with the single exception of the study conducted by Kamaleldin et al., 11 where reoptimized plans were also evaluated.…”

Section: Introductionmentioning

confidence: 99%

“…A number of papers were dedicated specifically to the dosimetric effects of the Type C algorithms in the HN plans. [9][10][11][12][13][14][15][16][17][18][19][20] The dose differences were particularly large in bone, 15,18 although some authors also noted differences in air. 9 The primary target dose heterogeneity often evaluated as D 2% /D 98% in the target was typically higher for the Type C algorithms.…”

Section: Introductionmentioning

confidence: 99%

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Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric‐modulated arc therapy planning

Feygelman

Latifi

Bowers

et al. 2022

J Applied Clin Med Phys

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Head and neck cancers present challenges in radiation treatment planning due to the large number of critical structures near the target(s) and highly heterogeneous tissue composition. While Monte Carlo (MC) dose calculations currently offer the most accurate approximation of dose deposition in tissue, the switch to MC presents challenges in preserving the parameters of care. The differences in dose‐to‐tissue were widely discussed in the literature, but mostly in the context of recalculating the existing plans rather than reoptimizing with the MC dose engine. Also, the target dose homogeneity received less attention. We adhere to strict dose homogeneity objectives in clinical practice. In this study, we started with 21 clinical volumetric‐modulated arc therapy (VMAT) plans previously developed in Pinnacle treatment planning system. Those plans were recalculated “as is” with RayStation (RS) MC algorithm and then reoptimized in RS with both collapsed cone (CC) and MC algorithms. MC statistical uncertainty (0.3%) was selected carefully to balance the dose computation time (1–2 min) with the planning target volume (PTV) dose‐volume histogram (DVH) shape approaching that of a “noise‐free” calculation. When the hot spot in head and neck MC‐based treatment planning is defined as dose to 0.03 cc, it is exceedingly difficult to limit it to 105% of the prescription dose, as we were used to with the CC algorithm. The average hot spot after optimization and calculation with RS MC was statistically significantly higher compared to Pinnacle and RS CC algorithms by 1.2 and 1.0 %, respectively. The 95% confidence interval (CI) observed in this study suggests that in most cases a hot spot of ≤107% is achievable. Compared to the 95% CI for the previous clinical plans recalculated with RS MC “as is” (upper limit 108%), in real terms this result is at least as good or better than the historic plans.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric‐modulated arc therapy planning

Feygelman

Latifi

Bowers

et al. 2022

J Applied Clin Med Phys

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“…For AXB-Dw, there was no clear trend; this result was consistent with that of another study. 37 Sayah 4 considered that the difference in D 2 % was dependent on the percentage of a high-density material in the PTV, where the AXB-Dw plans predicted higher dose values than the AAA plans. This may clarify our results.…”

Section: Discussionmentioning

confidence: 99%

“…Some researchers clarified that the largest dosimetric differences always occurred in the highest density region, where AXB-Dw predicted higher dose values than AXB-Dm. 4 , 20 …”

Section: Introductionmentioning

confidence: 99%

Radiobiological Comparison of Acuros External Beam and Anisotropic Analytical Algorithm on Esophageal Carcinoma Radiotherapy Treatment Plans

et al. 2022

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Objective The present study aimed to investigate the dose differences and radiobiological assessment between Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB) with its 2 calculation models, namely, dose-to-water (AXB-Dw) and dose-to-medium (AXB-Dm), on esophageal carcinoma radiotherapy treatment plans. Materials and methods The AXB-Dw and AXB-Dm plans were generated by recalculating the initial 66 AAA plans using the AXB algorithm with the same monitor units and beam parameters as those in the original plan. The dosimetric and radiobiological assessment parameters were calculated for the planning target volume (PTV) and organs at risk (OARs). The gamma agreement for the PTV and the correlation between it and the volume of the air cavity and bone among the different algorithms were compared simultaneously. The dose discrepancy between the theoretical calculation and treatment planning system (TPS) when switching from AXB-Dm to AXB-Dw was analyzed according to the composition of the structures. Results The PTV dose of AXB-Dm plans was significantly smaller than that of the AAA and AXB-Dw plans (P < .05), except for D2. The difference values for AAA vs AXB-Dm (∆ Dx,(AAA-AXB,Dm)) and AXB-Dw vs AXB-Dm (∆ Dx,(AXB,Dw-AXB,Dm)) were 1.94% [1.27%, 2.64%] and 1.95% [1.56%, 2.27%], respectively. For the spinal cord and heart, there were obvious differences between the AAA vs AXB-Dm (spinal cord: 1.15%, heart: 2.89%) and AXB-Dw vs AXB-Dm (spinal cord: 1.88%, heart: 3.25%) plans. For the lung, the differences between AAA vs AXB-Dm and AAA vs AXB-Dw were significantly larger than those of AXB-Dm vs AXB-Dw. Compared to the case of AAA and AXB-Dw, the decrease in biologically effective dose (BED10, [Formula: see text]) of AXB-Dm due to dose non-uniformity exceeded 6.5%, even for a small [Formula: see text]. The average values of equivalent uniform dose in the AAA, AXB-Dw, and AXB-Dm plans were 52.03±.39 Gy, 52.24 ± .81 Gy, and 51.13 ± .47 Gy, respectively. The tumor control probability (TCP) results for PTV in the AAA, AXB-Dw, and AXB-Dm plans were 62.29 ± 1.57%, 62.82 ± 1.69%, and 58.68±1.88%, respectively. With the 2%/2 mm and 3%/3 mm acceptance criteria, the mean values of [Formula: see text], [Formula: see text], and [Formula: see text] were 87.24, 63.3, and 64.81% vs 97.86, 91.77, and 89.25%, respectively. The dose discrepancy between the theoretical calculation and TPS when switching from AXB-Dm to AXB-Dw was approximately 1.63%. Conclusions The AAA and AXB-Dw algorithms overestimated the radiobiological parameters when the tumor particularly consisted of nonuniform tissues. A relatively small dose difference could cause a significant reduction in the corresponding TCP. Dose distribution algorithms should be carefully chosen by physicists and oncologists to improve tumor control, as well as to optimize OARs protection.

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Dosimetric and Radiobiological Impact of Flattening Filter‐Free Beam and Dose Calculation Algorithm Using RapidArc Plans for Cervical Cancer Treatment

Manna,

Singh,

Gupta

et al. 2023

Precision Radiation Oncology

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PurposeThe aim of this study is to quantify the potential benefits of a flattening filter‐free (FFF) beam and implement a dose‐computation algorithm for cervical radiotherapy through dosimetric and radiobiological analyses using RapidArc.MethodsThirty‐three patients were enrolled, and four RapidArc plans were created for each patient using a dual‐arc flattening filter and 6‐MV FFF photon beams for the two calculation algorithms. Homogeneity index (HI), conformity index (CI), target coverage, monitor units (MUs), and organ‐at‐risk (OAR) dosimetric characteristics were compared between the plans. Radiobiological characteristics and normal tissue complication probability (NTCP) scores were computed for the OAR using different biological models.ResultsNo significant differences were observed in the Dmax, D98%, and CI in the planning target volume (PTV). Both computations estimated a significant difference in V95%, D2%, and HI for the PTV. Furthermore, the FFF beam showed a significant increase in the MUs and a significant reduction in V30% for the femoral heads. The NTCP score showed a significant increase in the late effects on the bladder, rectum, and bowel with FFF beams.ConclusionThe current study recommends FFF beams for better conformity, comparable dose coverage for the target, and OAR sparing invariable to the dose computation algorithm. The difference in the NTCP score for OAR was minimal with the FFF beam.

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Dosimetric impact of switching from AAA to Acuros dose-to-water and dose-to-medium for RapidArc plans of nasopharyngeal carcinomas

Cited by 7 publications

References 27 publications

Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric‐modulated arc therapy planning

Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric‐modulated arc therapy planning

Radiobiological Comparison of Acuros External Beam and Anisotropic Analytical Algorithm on Esophageal Carcinoma Radiotherapy Treatment Plans

Dosimetric and Radiobiological Impact of Flattening Filter‐Free Beam and Dose Calculation Algorithm Using RapidArc Plans for Cervical Cancer Treatment

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