State of dose prescription and compliance to international standard (ICRU-83) in intensity modulated radiation therapy among academic institutions

Das, Indra J.; Andersen, Aaron; Chen, Zhe Jay; Dimofte, Andreea; Glatstein, Eli; Hoisak, Jeremy; Huang, Long; Langer, Márk; Lee, Choonik; Pacella, M; Popple, Richard A.; Rice, R.; Smilowitz, Jennifer B.; Sponseller, Patricia A.; Zhu, Timothy C.

doi:10.1016/j.prro.2016.11.003

Cited by 44 publications

(27 citation statements)

References 33 publications

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“…Both, MP – VMAT and 6 MV SE – VMAT, plans were compared using the DVH criteria for both cases. The homogeneity index (HI) reported in the ICRU 83 (HI = 0, for a perfectly homogenous dose distribution) was used for the PTV dose distributions . It includes the near‐minimum (

D_{2 \%}

) and near‐maximum (

D_{98 \%}

) dose to report maximum and minimum doses for target structures.…”

Section: Methodsmentioning

confidence: 99%

“…The homogeneity index (HI) reported in the ICRU 83 (HI = 0, for a perfectly homogenous dose distribution) was used for the PTV dose distributions. 22 It includes the near-minimum (D 2% ) and near-maximum (D 98% ) dose to report maximum and minimum doses for target structures. The D 50% represents the dose delivered to 50% of the structure.…”

Section: H Dosimetric Parametersmentioning

confidence: 99%

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Simultaneous optimization of mixed photon energy beams in volumetric modulated arc therapy

et al. 2019

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Purpose Despite the availability of multiple energy photon beams on clinical linear accelerators, volumetric modulated arc therapy (VMAT) optimization is currently limited to a single photon beam. The purpose of this work was to present a proof‐of‐principle study on an algorithm for simultaneous optimization of mixed photon beams for VMAT (MP – VMAT), utilizing an additional photon energy as an additional degree of freedom. Methods The MP – VMAT optimization algorithm is presented as a two‐step heuristic approach. First, a convex linear programming problem is solved for simultaneous optimization of nonuniform dual energy intensity maps (DEIMs) for an angular resolution of 36 equi‐spaced beam segments. Subsequently, for a given gantry speed schedule, the second step aims to best replicate each DEIM by dispersing MP – VMAT apertures along with their corresponding intensities over their respective beam segment. This constitutes a nonlinear problem, which is linearized using McCormick relaxation. The final large‐scale mixed integer linear programming (MILP) dispersion model ensures a contiguous and smooth transition of multileaf collimators (MLCs) from one beam segment to the next. To demonstrate the proof‐of‐principle, we first compared the quality of dose volume histograms (DVHs) of MP – VMAT to the ones calculated from 36 DEIMs following the step 1 of MP – VMAT model. Additionally, the MLCs motion violations were evaluated for the complete 360° gantry rotation for gantry speeds ranging from 1 to 6° per second. The quality of MP – VMAT plans were also compared to conventional single energy VMAT plans via DVH, homogeneity index (HI), and conformity number (CN) for two prostate cases. Results The MP – VMAT model resulted in a successful convergence of DVHs relative to the ones from DEIMs with HI and CN of 0.05 and 0.9, respectively, for 1 and 2° per second gantry speed schedules. In replicating the DEIMs, the MILP dispersion model was able to achieve optimality for almost all segments at 1° per second and for majority of segments at 2° per second. Although, DVHs quality was slightly inferior for 3° per second gantry speed, the target conformity of 0.9 and heterogeneity of 0.08 were achievable even for the suboptimal solutions. No violations of the MLC constraints were observed throughout the complete 360 degree arc rotation for any gantry speed schedule, thereby confirming MILP dispersion model. For the two prostate cases, the results showed MP – VMAT's ability to achieve substantial dose reduction in rectum and bladder while yielding similar target coverage compared to single energy VMAT. Bladder volume was mostly spared in low‐to‐intermediate dose region. Rectal volume sparing (3 % to 12 %) was observed in the intermediate (from 25 to 50 Gy) dose region. Conclusion We demonstrate the first formalism of a large‐scale simultaneous optimization of mixed photon energy beams for VMAT. Dosimetric comparison of MP – VMAT to single energy VMAT demonstrated potential advantages of using mixed photon energy beams for prostat...

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D_{2 \%}

) and near‐maximum (

D_{98 \%}

) dose to report maximum and minimum doses for target structures.…”

Section: Methodsmentioning

confidence: 99%

Section: H Dosimetric Parametersmentioning

confidence: 99%

Simultaneous optimization of mixed photon energy beams in volumetric modulated arc therapy

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Therefore, ICRU 83 states D 50% to be the true replacement of the former ICRU reference point. For the same reason, some authors recommend D 50% as the value of dose prescription . In terms of prescription, however, the authors of the ICRU 83 report respect the freedom to prescribe to any value, for example, “(…) if a radiation oncologist concludes that a larger fractional V than 50% is biologically relevant”.…”

Section: Technical Principles and Definitions Of Terms In Imrtmentioning

confidence: 99%

“…In human radiation oncology, Das et al . recently reported on the desolate dose prescription compliance to the international standard in IMRT (ICRU 83).…”

Section: Intensity‐modulated Radiation Therapy In Human Medicinementioning

confidence: 99%

“…Das et al. attribute this pattern to be “an extension of the 3D‐CRT practice that may not be appropriate in IMRT” . However, if screened in detail, the authors of ICRU 83 report respect the radiation oncologist's freedom to prescribe any value, and while D 50% is often chosen for various reasons (see Section 2.2): (…) “The report does not recommend any particular value of V in D V for a prescription”…”

Section: Intensity‐modulated Radiation Therapy In Human Medicinementioning

confidence: 99%

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Intensity‐modulated radiation therapy dose prescription and reporting: Sum and substance of the International Commission on Radiation Units and Measurements Report 83 for veterinary medicine

Bley

Meier

Besserer

et al. 2019

Vet Radiology Ultrasound

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Institutions' adherence to protocol, quality assurance, and radiation parameter reporting are key to adequately interpret and compare treatment outcomes in radiation oncology. In 2017, the editorial board for Veterinary Radiology & Ultrasound adapted author guidelines on "technical information for radiation therapy (RT)". These guidelines provide a framework to report the RT treatment process in manuscripts resulting from veterinary clinical trials. In spite of this framework, however, in implementing IMRT, we have identified different "interpretations" of the extended prescription and reporting recommendations of the International Commission on Radiation Units and Measurements (ICRU 83), even within our small team. In the following commentary review, we provide a short summary of various detailed aspects of the ICRU 83 recommended (IMRT) prescription and reporting, including (a) absorbed target dose specification and prescription, (b) homogeneity and conformity, and (c) reporting of absorbed dose in organs at risk. In particular, we want to share our thoughts on possible dangers of noncompliance in adhering to protocol, prescription, and reporting. As veterinary IMRT publications still sparsely adhere to the recommendations of the ICRU, we were motivated to summarize the recommendations to facilitate appropriate reporting for IMRT in future veterinary studies. K E Y W O R D SIMRT, normalization, treatment planning, veterinary

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Treatment plan quality control using multivariate control charts

et al. 2021

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Statistical process control tools such as control charts were recommended by the American Association of Physicists in Medicine (AAPM) Task Group 218 for radiotherapy quality assurance. However, the tools needed to analyze multivariate, correlated data that are often encountered in treatment plan quality measures, are lacking. In this study, we develop quality control tools that can model multivariate plan quality measures with correlations and account for patient-specific risk factors, without adding a significant burden to clinical workflow. Methods and Materials: A multivariate, quality control chart is developed that includes a risk-adjustment model, Hotelling's T 2 statistic, and principal component analysis (PCA). Principal component analysis accounts for correlations among a set of organ-at-risk (OAR) dose-volume histogram (DVH) points that serves as proxies for plan quality. Risk-adjustment models estimate the principal components from PCA using a set of patient-and treatment-specific risk factors. The resulting residuals from the risk-adjustment models are used to compute the Hotelling's T 2 statistic; the corresponding multivariate control chart is then plotted based on the beta distribution followed by the statistic. Further, the box-cox transformation is used to account for non-normality in DVH points. We investigate the application of the proposed methodology via three multivariate control chartsa conventional chart that ignores risk-adjustment and PCA, a risk-adjusted chart ignoring PCA, and a PCA-based, risk-adjusted chart. These control charts are evaluated on 69 head-and-neck cases. Results: The conventional multivariate control chart fails to account for important patient-specific risk factors, including volumes and cross-sectional areas of the tumor and OARs and distances in-between. This failure leads to a larger number of false alarms. While the multivariate risk-adjusted control chart is able to reduce false alarms, it fails to account for correlations in DVH points. The multivariate PCA-based, risk-adjusted control chart can detect unusual plans after accounting for the correlations. By replanning, improvements are shown on an unusual plan identified by both risk-adjusted methods. Conclusions: The multivariate risk-adjusted control chart developed here enables quality control of plans prior to delivery. This methodology is generic and can be readily applied for other radiotherapy quality assurance protocols, such as gamma analysis pass rates.

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State of dose prescription and compliance to international standard (ICRU-83) in intensity modulated radiation therapy among academic institutions

Cited by 44 publications

References 33 publications

Simultaneous optimization of mixed photon energy beams in volumetric modulated arc therapy

Simultaneous optimization of mixed photon energy beams in volumetric modulated arc therapy

Intensity‐modulated radiation therapy dose prescription and reporting: Sum and substance of the International Commission on Radiation Units and Measurements Report 83 for veterinary medicine

Treatment plan quality control using multivariate control charts

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