Evaluation of DVH-based treatment plan verification in addition to gamma passing rates for head and neck IMRT

Visser, Ruurd; Wauben, D.J.L.; Groot, Martijn de; Steenbakkers, Roel J.H.M.; Bijl, H.P.; Godart, J.; Veld, Aart A. van ‘t; Langendijk, Johannes A.; Korevaar, Erik W

doi:10.1016/j.radonc.2014.08.002

Cited by 23 publications

(34 citation statements)

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“…Patient-specific pre-treatment quality assurance (QA) is necessary for the implementation of IMRT [3], and it has been a consensus of the researcher community that patient-specific QA can be done by film dosimetry combined with ionization chambers measurement [4–6], or by a 2D/3D detector arrays test in a phantom to compare and validate the dose accuracy of the treatment [7–10]. Most of these pre-treatment QA use the ‘γ evaluation method’ for the result analysis, which is a composite analysis of distance-to-agreement (DTA) and dose difference (DD) [11–13]. …”

Section: Introductionmentioning

confidence: 99%

Retrospective dosimetry study of intensity-modulated radiation therapy for nasopharyngeal carcinoma: measurement-guided dose reconstruction and analysis

et al. 2018

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BackgroundConventional phantom-based planar dosimetry (2D-PBD) quality assurance (QA) using gamma pass rate (GP (%)) is inadequate to reflect clinically relevant dose error in intensity-modulated radiation therapy (IMRT), owing to a lack of information regarding patient anatomy and volumetric dose distribution. This study aimed to evaluate the dose distribution accuracy of IMRT delivery for nasopharyngeal carcinoma (NPC), which passed the 2D-PBD verification, using a measurement-guided 3D dose reconstruction (3D-MGR) method.MethodsRadiation treatment plans of 30 NPC cases and their pre-treatment 2D-PBD data were analyzed. 3D dose distribution was reconstructed on patient computed tomography (CT) images using the 3DVH software and compared to the treatment plans. Global and organ-specific dose GP (%), and dose-volume histogram (DVH) deviation of each structure was evaluated. Interdependency between GP (%) and the deviation of the volumetric dose was studied through correlation analysis.ResultsThe 3D-MGR achieved global GP (%) similar to conventional 2D-PBD in the same criteria. However, structure-specific GP (%) significantly decreased under stricter criteria, including the planning target volume (PTV). The average deviation of all inspected dose volumes (DV) and volumetric dose (VD) parameters ranged from − 2.93% to 1.17%, with the largest negative deviation in V100% of the PTVnx of − 15.66% and positive deviation in D1cc of the spinal cord of 6.66%. There was no significant correlation between global GP (%) of 2D-PBD or 3D-MGR and the deviation of the most volumetric dosimetry parameters (DV or VD), when the Pearson’s coefficient value of 0.8 was used for correlation evaluation.ConclusionEven upon passing the pre-treatment phantom based dosimetric QA, there could still be risk of dose error like under-dose in PTVnx and overdose in critical structures. Measurement-guided 3D volumetric dosimetry QA is recommended as the more clinically efficient verification for the complicated NPC IMRT.Electronic supplementary materialThe online version of this article (10.1186/s13014-018-0993-2) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Retrospective dosimetry study of intensity-modulated radiation therapy for nasopharyngeal carcinoma: measurement-guided dose reconstruction and analysis

et al. 2018

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“…(6) DVH-based quality assurance (hereafter referred to as the "Planned Dose Perturbation method" used in 3DVH (Sun Nuclear, Melbourne, FL)) has been discussed by various groups recently. (7)(8)(9)(10)(11)(12) Validations of this DVH-based QA have been performed by different researchers, proving that dose reconstructed via 3DVH is consistent with dose reconstructed through other detectors and algorithms. (6,(13)(14) Significant errors were discovered via DVH-based QA, where the GI/DTA methods did not find the errors, indicating potential pitfalls in using recommended GI/DTA metrics and action levels.…”

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confidence: 77%

“…DVH‐based quality assurance (hereafter referred to as the “Planned Dose Perturbation method” used in 3DVH (Sun Nuclear, Melbourne, FL)) has been discussed by various groups recently 7 , 8 , 9 , 10 , 11 , 12 . Validations of this DVH‐based QA have been performed by different researchers, proving that dose reconstructed via 3DVH is consistent with dose reconstructed through other detectors and algorithms 6 , 13 , 14 .…”

Section: Introductionmentioning

confidence: 87%

“…Positive results were also reported by the GI analysis method when numerous types of errors, including MLC positioning errors, wrong dynamic wedge angle, cold/hot spots of varied sizes, and collimator rotation errors were introduced to test the sensitivity of DVH‐based QA 9 , 11 , 16 . To overcome the limitations of traditional evaluation, a hybrid QA concept, involving a combination of DVH‐based QA and GI analysis, has been recommended 8 , 17 …”

Section: Introductionmentioning

confidence: 99%

“…(9,11,16) To overcome the limitations of traditional evaluation, a hybrid QA concept, involving a combination of DVH-based QA and GI analysis, has been recommended. (8,17) In this study, three types of clinically relevant errors were introduced into deliverable treatment plans to test the sensitivity of 3DVH software. The ability of 3DVH software to, first, detect these errors and, second, properly to account for the error through evaluation of delivered DVH, was studied.…”

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Accuracy of one algorithm used to modify a planned DVH with data from actual dose delivery

Podgorsak

Kumaraswamy

2016

J Applied Clin Med Phys

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Detection and accurate quantification of treatment delivery errors is important in radiation therapy. This study aims to evaluate the accuracy of DVH based QA in quantifying delivery errors. Eighteen previously treated VMAT plans (prostate, H&N, and brain) were randomly chosen for this study. Conventional IMRT delivery QA was done with the ArcCHECK diode detector for error‐free plans and plans with the following modifications: 1) induced monitor unit differences up to ±3.0%,2) control point deletion (3, 5, and 8 control points were deleted for each arc), and 3) gantry angle shift (2° uniform shift clockwise and counterclockwise). 2D and 3D distance‐to‐agreement (DTA) analyses were performed for all plans with SNC Patient software and 3DVH software, respectively. Subsequently, accuracy of the reconstructed DVH curves and DVH parameters in 3DVH software were analyzed for all selected cases using the plans in the Eclipse treatment planning system as standard. 3D DTA analysis for error‐induced plans generally gave high pass rates, whereas the 2D evaluation seemed to be more sensitive to detecting delivery errors. The average differences for DVH parameters between each pair of Eclipse recalculation and 3DVH prediction were within 2% for all three types of error‐induced treatment plans. This illustrates that 3DVH accurately quantifies delivery errors in terms of actual dose delivered to the patients. 2D DTA analysis should be routinely used for clinical evaluation. Any concerns or dose discrepancies should be further analyzed through DVH‐based QA for clinically relevant results and confirmation of a conventional passing‐rate‐based QA.PACS number(s): 87.56.Fc, 87.55.Qr, 87.55.dk, 87.55.km

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Comparison of DVH‐based plan verification methods for VMAT: ArcCHECK‐3DVH system and dynalog‐based dose reconstruction

Saito

Sato

Ito

et al. 2017

J Applied Clin Med Phys

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The purpose of this study was comparing dose‐volume histogram (DVH)‐based plan verification methods for volumetric modulated arc therapy (VMAT) pretreatment QA. We evaluated two 3D dose reconstruction systems: ArcCHECK‐3DVH system (Sun Nuclear corp.) and Varian dynalog‐based dose reconstruction (DBDR) system, developed in‐house. Fifteen prostate cancer patients (67.6 Gy/26 Fr), four head and neck cancer patient (66 Gy/33 Fr), and four esophagus cancer patients (60 Gy/30 Fr) treated with VMAT were studied. First, ArcCHECK measurement was performed on all plans; simultaneously, the Varian dynalog data sets that contained the actual delivered parameters (leaf positions, gantry angles, and cumulative MUs) were acquired from the Linac control system. Thereafter, the delivered 3D patient dose was reconstructed by 3DVH software (two different calculating modes were used: High Sensitivity (3DVH‐HS) and Normal Sensitivity (3DVH‐NS)) and in‐house DBDR system. We evaluated the differences between the TPS‐calculated dose and the reconstructed dose using 3D gamma passing rates and DVH dose index analysis. The average 3D gamma passing rates (3%/3 mm) between the TPS‐calculated dose and the reconstructed dose were 99.1 ± 0.6%, 99.7 ± 0.3%, and 100.0 ± 0.1% for 3DVH–HS, 3DVH–NS, and DBDR, respectively. For the prostate cases, the average differences between the TPS‐calculated dose and reconstructed dose in the PTV mean dose were 1.52 ± 0.50%, −0.14 ± 0.55%, and −0.03 ± 0.07% for 3DVH–HS, 3DVH–NS, and DBDR, respectively. For the head and neck and esophagus cases, the dose difference to the TPS‐calculated dose caused by an effect of heterogeneity was more apparent under the 3DVH dose reconstruction than the DBDR. Although with some residual dose reconstruction errors, these dose reconstruction methods can be clinically used as effective tools for DVH‐based QA for VMAT delivery.

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Evaluation of DVH-based treatment plan verification in addition to gamma passing rates for head and neck IMRT

Cited by 23 publications

References 21 publications

Retrospective dosimetry study of intensity-modulated radiation therapy for nasopharyngeal carcinoma: measurement-guided dose reconstruction and analysis

Retrospective dosimetry study of intensity-modulated radiation therapy for nasopharyngeal carcinoma: measurement-guided dose reconstruction and analysis

Accuracy of one algorithm used to modify a planned DVH with data from actual dose delivery

Comparison of DVH‐based plan verification methods for VMAT: ArcCHECK‐3DVH system and dynalog‐based dose reconstruction

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