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Walker LS, Byrne JP. Clinical impact of DVH uncertainties. Med Dosim 2024:S0958-3947(24)00031-1. [PMID: 38987038 DOI: 10.1016/j.meddos.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 03/26/2024] [Accepted: 06/11/2024] [Indexed: 07/12/2024]
Abstract
Dose-volume histograms (DVH), along with dose and volume metrics, are central to radiotherapy planning. As such, errors have the potential to significantly impact the selection of appropriate treatment plans. Dose distributions that pass tests in one TPS may fail the same tests when transferred to another, even if using identical structures and dose grid information. This work shows the design and implementation of methods for assessing the accuracy of dose and volume computations performed by treatment planning systems (TPS), and other analytical tools. We demonstrate examples where differences in calculations between systems can change the assessment of a plan's clinical acceptability. Our work also provides a more detailed DVH analysis of single targets than earlier published studies. This is relevant for SRS plans and small structure dose assessments. Very small structures are a particular problem because of their coarse digital representation, and the impact of this is thoroughly examined. Reference DVH curves were derived mathematically, based on Gaussian dose distributions centered on spherical structures. The structures and dose distributions were generated synthetically, and imported into RayStation, MasterPlan, and ProKnow. Corresponding DVHs were analytically derived and taken as ground truth references, for comparison with the commercial DVH calculations. Two commonly used dose metrics PCI and MGI were used to determine the limit of calculation accuracy for small structures. In addition, to measure the DVH differences between a larger range of commercial DVH calculators, the D95 metric from a set of real clinical plans was compared across both the 3 DVH calculators under test, and across a further six TPSs from other hospitals. We show that even slight deviations between the results of DVH calculators can lead to plan check failures, and we illustrate this with the commonly used D95 planning metric. We present clinical data across eight planning systems that highlight instances where plan checks would pass in one software and fail in another due to DVH calculation differences. For the smallest volumes tested, errors of up to 20% were observed in the DVHs. RayStation was tested down to a 3 mm radius sphere (≈0.1 cc) and this showed close to 10% error, reducing to 1% for 10 mm radius (≈4.0 cc) and 0.1% for 20 mm radius (≈33 cc). In clinical plans, the variation in D95 was up to 9% for the smallest volumes, and typically around 2% in the range 0.5 cc-20 cc, and 1% in 20 cc-70 cc, falling to <0.1% for large volumes. Paddick Conformity Index (PCI) and Modified Gradient Index (MGI) are commonly used plan quality indicators for very small volumes. For volumes ≈0.1 cc we observed errors of up to 40% in PCI, and up to 75% in MGI. Our study extends the range of tested DVH calculators in published work, and shows their performance over a wider range of volume sizes. We provide quantitative evidence of the critical need to test the accuracy of DVH calculators in the TPS before clinical use. This work is particularly relevant for both stereotactic plan evaluation and for assessment of small volume doses in published dose constraint recommendations. We demonstrate that significant errors can occur in DVHs for volumes less than 1 cc, even if the volumes themselves are calculated accurately. Even for large structures, deviations between the outputs of DVH calculators can lead to indicated or reported plan check failures if they do not include appropriate tolerances. We urge caution in the use of DVH metrics for these very small volumes and recommend that appropriate DVH uncertainty tolerances are set in organ dose constraints when using them to evaluate clinical plans.
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Affiliation(s)
- L S Walker
- Radiotherapy Physics, Northern Centre for Cancer Care, Newcastle Upon Tyne NHS Foundation Trust, Newcastle Upon Tyne, Tyne and Wear, UK.
| | - J P Byrne
- Radiotherapy Physics, Northern Centre for Cancer Care, Newcastle Upon Tyne NHS Foundation Trust, Newcastle Upon Tyne, Tyne and Wear, UK
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Penoncello GP, Voss MM, Gao Y, Sensoy L, Cao M, Pepin MD, Herchko SM, Benedict SH, DeWees TA, Rong Y. Multicenter Multivendor Evaluation of Dose Volume Histogram Creation Consistencies for 8 Commercial Radiation Therapy Dosimetric Systems. Pract Radiat Oncol 2024; 14:e236-e248. [PMID: 37914082 DOI: 10.1016/j.prro.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/11/2023] [Accepted: 09/26/2023] [Indexed: 11/03/2023]
Abstract
PURPOSE To evaluate dose volume histogram (DVH) construction differences across 8 major commercial treatment planning systems (TPS) and dose reporting systems for clinically treated plans of various anatomic sites and target sizes. METHODS AND MATERIALS Dose files from 10 selected clinically treated plans with a hypofractionation, stereotactic radiation therapy prescription or sharp dose gradients such as head and neck plans ranging from prescription doses of 18 Gy in 1 fraction to 70 Gy in 35 fractions, each calculated at 0.25 and 0.125 cm grid size, were created and anonymized in Eclipse TPS, and exported to 7 other major TPS (Pinnacle, RayStation, and Elements) and dose reporting systems (MIM, Mobius, ProKnow, and Velocity) systems for comparison. Dose-volume constraint points of clinical importance for each plan were collected from each evaluated system (D0.03 cc [Gy], volume, and the mean dose were used for structures without specified constraints). Each reported constraint type and structure volume was normalized to the value from Eclipse for a pairwise comparison. A Wilcoxon rank-sum test was used for statistical significance and a multivariable regression model was evaluated adjusting for plan, grid size, and distance to target center. RESULTS For all DVH points relative to Eclipse, all systems reported median values within 1.0% difference of each other; however, they were all different from Eclipse. Considering mean values, Pinnacle, RayStation, and Elements averaged at 1.038, 1.046, and 1.024, respectively, while MIM, Mobius, ProKnow, and Velocity reported 1.026, 1.050, 1.033, and 1.022, respectively relative to Eclipse. Smaller dose grid size improved agreement between the systems marginally without statistical significance. For structure volumes relative to Eclipse, larger differences are seen across all systems with a range in median values up to 3.0% difference and mean up to 10.1% difference. CONCLUSIONS Large variations were observed between all systems. Eclipse generally reported, at statistically significant levels, lower values than all other evaluated systems. The nonsignificant change resulting from lowering the dose grid resolution indicates that this resolution may be less important than other aspects of calculating DVH curves, such as the 3-dimensional modeling of the structure.
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Affiliation(s)
- Gregory P Penoncello
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona; Department of Radiation Oncology, University of Colorado, Aurora, Colorado
| | - Molly M Voss
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Scottsdale, Arizona
| | - Yu Gao
- Department of Radiation Oncology, Stanford University, Palo Alto, California
| | - Levent Sensoy
- Department of Radiation Oncology, University of Miami, Miami, Florida
| | - Minsong Cao
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Mark D Pepin
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Steven M Herchko
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida
| | - Stanley H Benedict
- Department of Radiation Oncology, University of California Davis, Sacramento, California
| | - Todd A DeWees
- Department of Computational and Quantitative Medicine, City of Hope, Duarte, California; Department of Radiation Oncology, City of Hope, Duarte, California.
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona.
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Liu C, Cho Y, Magnelli A, Angelov L, Balagamwala EH, Chao ST, Xia P. The dosimetric impact of titanium implants in spinal SBRT using four commercial treatment planning algorithms. J Appl Clin Med Phys 2023; 24:e14070. [PMID: 37540084 PMCID: PMC10562029 DOI: 10.1002/acm2.14070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 05/03/2023] [Accepted: 05/29/2023] [Indexed: 08/05/2023] Open
Abstract
To evaluate the dosimetric impact of titanium implants in spine SBRT using four dose calculation algorithms. Twenty patients with titanium implants in the spine treated with SBRT without density override (DO) were selected. The clinical plan for each patient was created in Pinnacle and subsequently imported into Eclipse (AAA and AcurosXB) and Raystation (CC) for dose evaluation with and without DO to the titanium implant. We renormalized all plans such that 90% of the tumor volume received the prescription dose and subsequently evaluated the following dose metrics: (1) the maximum dose to 0.03 cc (Dmax), dose to 99% (D99%) and 90% (D90%) of the tumor volume; (2) Dmax and volumetric metrics of the spinal cord. For the same algorithm, plans with and without DO had similar dose distributions. Differences in Dmax, D99% and D90% of the tumor were on average <2% with slightly larger variations up to 5.58% in Dmax using AcurosXB. Dmax of the spinal cord for plans calculated with DO increased but the differences were clinically insignificant for all algorithms (mean: 0.36% ± 0.7%). Comparing to the clinical plans, the relative differences for all algorithms had an average of 1.73% (-10.36%-13.21%) for the tumor metrics and -0.93% (-9.87%-10.95%) for Dmax of the spinal cord. A few cases with small tumor and spinal cord volumes, dose differences of >10% in both D99% and Dmax of the tumor, and Dmax of the spinal cord were observed. For all algorithms, the presence of titanium implants in the spine for most patients had minimal impact on dose distributions with and without DO. For the same plan calculated with different algorithms, larger differences in volumetric metrics of >10% could be observed, impacted by dose gradient at the plan normalization volume, tumor volumes, plan complexity, and partial voxel volume interpolation.
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Affiliation(s)
- Chieh‐Wen Liu
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Young‐Bin Cho
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Anthony Magnelli
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Lilyana Angelov
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Ehsan H. Balagamwala
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Samuel T. Chao
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
| | - Ping Xia
- Department of Radiation Oncology, Taussig Cancer InstituteCleveland ClinicClevelandOhioUSA
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Olch AJ, Gopalakrishnan M, Murphy ES, MacDonald SM, Hua CH. Toward Systematic Assessment and Improvement of Radiation Therapy Plan Quality of Cooperative Group Trial Submissions: A Report From the Children's Oncology Group. Pract Radiat Oncol 2023; 13:e374-e382. [PMID: 37037758 PMCID: PMC11163894 DOI: 10.1016/j.prro.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 04/12/2023]
Abstract
PURPOSE This study evaluates the quality of plans used for the treatment of patients in the Children's Oncology Group study ACNS1123. Plan quality is quantified based on a scoring system specific to the protocol. In this way, the distribution of plan quality scores is determined that can be used to identify plan quality issues for this study and for future plan quality improvement. METHODS AND MATERIALS ACNS1123 stratum 1 patients (70) were evaluated. This included 50 photon and 20 proton plans. Digital Imaging and Communications in Medicine (DICOM) structure and dose data were obtained from the Children's Oncology Group. A commercially available plan quality scoring algorithm was used to create a scoring system we designed using the protocol dosimetric requirements. The whole ventricle and boost planning target volumes (PTVs) could earn a maximum of 70 points, whereas the organs at risk could earn 30 points (total maximum score of 100 points). The scoring algorithm adjusted scores based on the difficulty in achieving the structure dose requirements, which depended on the proximity of the PTVs and the dose gradients achieved relative to the organs at risk. The distribution of plan scores was used to determine the mean, median, and range of scores. RESULTS The median adjusted plan quality scores for the 20 proton and 50 photon plans were 83.3 and 86.9, respectively. The range of adjusted scores (maximum to minimum) was 50 points. The average score adjustment was 7.4 points. Photon and proton plans performed almost equally. Average plan quality by individual structure revealed that the brain stem, PTV boost, and cochlea lost the most points. CONCLUSIONS This report is the first to systematically analyze overall radiation therapy plan quality scores for an entire cohort of patients treated in a cooperative group clinical trial. The methodology demonstrated a large variation in plan quality in this trial. Future clinical trials could potentially use this method to reduce plan quality variability, which may improve outcomes.
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Affiliation(s)
- Arthur J Olch
- Department of Radiation Oncology, University of Southern California and Children's Hospital Los Angeles, Los Angeles, California.
| | | | - Erin S Murphy
- Department of Radiation Oncology, Cleveland Clinic, Cleveland, Ohio
| | - Shannon M MacDonald
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Chia-Ho Hua
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee
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5
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Boukerroui D, Vasquez Osorio E, Brunenberg E, Gooding MJ. Analytic calculations and synthetic shapes for validation of quantitative contour comparison software. Phys Imaging Radiat Oncol 2023; 26:100436. [PMID: 37089904 PMCID: PMC10119950 DOI: 10.1016/j.phro.2023.100436] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/24/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
A high level of variability in reported values was observed in a recent survey of contour similarity measures (CSMs) calculation tools. Such variations in the output measurements prevent meaningful comparison between studies. The purpose of this study was to develop a dataset with analytically calculated gold standard values to facilitate standardization and ensure accuracy of CSM implementations. The dataset was generated in the Digital Imaging and Communications in Medicine (DICOM) format. Both the dataset and the software used for its generation are made publicly available to encourage robust testing of CSM implementations for accuracy, improving consistency between different implementations.
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Pepin MD, Brom KM, Gustafson JM, Long KM, Fong de Los Santos LE, Shiraishi S, Penoncello GP, Rong Y. Assessment of Dose-Volume Histogram Precision for Five Clinical Systems. Med Phys 2022; 49:6303-6318. [PMID: 35943829 DOI: 10.1002/mp.15916] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 06/29/2022] [Accepted: 07/22/2022] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To investigate the dependency of dose-volume histogram behavior (DVH) and precision on underlying DICOM discretization using shapes and dose distributions with known analytical DVHs for five commercial DVH calculators. METHODS DVHs and summary metrics were extracted from all five systems using synthetic DICOM cone and cylinder objects for which the true volume and DVH curves were known. Trends in the curves and metrics were explored by varying the underlying voxelization of the CT image, structure set, and dose grid as well by varying the geometry of the structure and direction of a linear dose gradient. Using synthetic structures allowed for comparison with ground-truth DVH curves to assess their accuracy while an algorithm was additionally developed to assess the precision of each system. The precision was calculated with a novel algorithm that treats any "stair step" behavior in a DVH curve as an uncertainty band and calculates the width, characterized as a percent difference, of the band for various DVH metrics. The underlying voxelization was additionally changed and DVHs were extracted for two clinical examples. The details of how each system calculated DVHs were also investigated and tendencies in the calculated curves, metrics, and precision were related to choices made in the calculation methodology. RESULTS Calculation methodology differences that had a noticeable impact on the DVH curves and summary metrics include supersampling beyond the input grids and interpretation of the superior and inferior ends of the structures. Amongst the systems studied, the median precision ranged from 0.902% to 3.22%, and interquartile ranges varied from 1.09% to 3.91%. CONCLUSIONS Commercial dose-evaluation solutions can calculate different DVH curves, structure volume measures, and dose statistics for the same input data due to differences in their calculation methodologies. This study highlights the importance of understanding and investigating the DVH calculation when considering a new clinical system and when using more than one system for data transfer. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mark D Pepin
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Kevin M Brom
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Jon M Gustafson
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Kenneth M Long
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | | | - Satomi Shiraishi
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Gregory P Penoncello
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA.,Department of Radiation Oncology, University of Colorado, Aurora, Colorado
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
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7
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Maliko N, Stam MR, Boersma LJ, Vrancken Peeters MJTFD, Wouters MWJM, KleinJan E, Mulder M, Essers M, Hurkmans CW, Bijker N. Transparency in quality of radiotherapy for breast cancer in the Netherlands: a national registration of radiotherapy-parameters. Radiat Oncol 2022; 17:73. [PMID: 35413924 PMCID: PMC9003170 DOI: 10.1186/s13014-022-02043-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
Background Radiotherapy (RT) is part of the curative treatment of approximately 70% of breast cancer (BC) patients. Wide practice variation has been reported in RT dose, fractionation and its treatment planning for BC. To decrease this practice variation, it is essential to first gain insight into the current variation in RT treatment between institutes. This paper describes the development of the NABON Breast Cancer Audit-Radiotherapy (NBCA-R), a structural nationwide registry of BC RT data of all BC patients treated with at least surgery and RT. Methods A working group consisting of representatives of the BC Platform of the Dutch Radiotherapy Society selected a set of dose volume parameters deemed to be surrogate outcome parameters, both for tumour control and toxicity. Two pilot studies were carried out in six RT institutes. In the first pilot study, data were manually entered into a secured web-based system. In the second pilot study, an automatic Digital Imaging and Communications in Medicine (DICOM) RT upload module was created and tested. Results The NBCA-R dataset was created by selecting RT parameters describing given dose, target volumes, coverage and homogeneity, and dose to organs at risk (OAR). Entering the data was made mandatory for all Dutch RT departments. In the first pilot study (N = 1093), quite some variation was already detected. Application of partial breast irradiation varied from 0 to 17% between the 6 institutes and boost to the tumour bed from 26.5 to 70.2%. For patients treated to the left breast or chest wall only, the average mean heart dose (MHD) varied from 0.80 to 1.82 Gy; for patients treated to the breast/chest wall only, the average mean lung dose (MLD) varied from 2.06 to 3.3 Gy. In the second pilot study 6 departments implemented the DICOM-RT upload module in daily practice. Anonymised data will be available for researchers via a FAIR (Findable, Accessible, Interoperable, Reusable) framework. Conclusions We have developed a set of RT parameters and implemented registration for all Dutch BC patients. With the use of an automated upload module registration burden will be minimized. Based on the data in the NBCA-R analyses of the practice variation will be done, with the ultimate aim to improve quality of BC RT. Trial registration Retrospectively registered.
Supplementary Information The online version contains supplementary material available at 10.1186/s13014-022-02043-0.
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Affiliation(s)
- Nansi Maliko
- Scientific Bureau, Dutch Institute for Clinical Auditing, Leiden, The Netherlands.,Department of Surgical Oncology, Netherlands Cancer Institute/Antoni Van Leeuwenhoek, Amsterdam, The Netherlands
| | | | - Liesbeth J Boersma
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Marie-Jeanne T F D Vrancken Peeters
- Department of Surgical Oncology, Netherlands Cancer Institute/Antoni Van Leeuwenhoek, Amsterdam, The Netherlands.,Department of Surgery, AmsterdamUMC, Amsterdam, the Netherlands
| | - Michel W J M Wouters
- Scientific Bureau, Dutch Institute for Clinical Auditing, Leiden, The Netherlands.,Department of Surgical Oncology, Netherlands Cancer Institute/Antoni Van Leeuwenhoek, Amsterdam, The Netherlands.,Department of Biomedical Data Sciences, Leiden University Medical Centre, Leiden, The Netherlands
| | - Eline KleinJan
- Trusted Third Party, Medical Research Data Management, Deventer, The Netherlands
| | - Maurice Mulder
- Trusted Third Party, Medical Research Data Management, Deventer, The Netherlands
| | | | - Coen W Hurkmans
- Department of Radiation Oncology, Catharina Hospital, Eindhoven, The Netherlands
| | - Nina Bijker
- Department of Radiation Oncology, AmsterdamUMC, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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Bismack B, Dolan J, Laugeman E, Gopal A, Wen N, Chetty I. Model refinement increases confidence levels and clinical agreement when commissioning a three-dimensional secondary dose calculation system. J Appl Clin Med Phys 2022; 23:e13590. [PMID: 35389554 PMCID: PMC9194992 DOI: 10.1002/acm2.13590] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/13/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose Evaluate custom beam models for a second check dose calculation system using statistically verifiable passing criteria for film analysis, DVH, and 3D gamma metrics. Methods Custom beam models for nine linear accelerators for the Sun Nuclear Dose Calculator algorithm (SDC, Sun Nuclear) were evaluated using the AAPM‐TG119 test suite (5 Intensity Modulated Radiation Therapy (IMRT) and 5 Volumetric Modulated Arc Therapy (VMAT) plans) and a set of clinical plans. Where deemed necessary, adjustments to Multileaf Collimator (MLC) parameters were made to improve results. Comparisons to the Analytic Anisotropic Algorithm (AAA), and gafchromic film measurements were performed. Confidence intervals were set to 95% per TG‐119. Film gamma criteria were 3%/3 mm (conventional beams) or 3%/1 mm (Stereotactic Radiosurgery [SRS] beams). Dose distributions in solid water phantom were evaluated based on DVH metrics (e.g., D95, V20) and 3D gamma criteria (3%/3 mm or 3%/1 mm). Film passing rates, 3D gamma passing rates, and DVH metrics were reported for HD MLC machines and Millennium MLC Machines. Results For HD MLC machines, SDC gamma film agreement was 98.76% ± 2.30% (5.74% CL) for 6FFF/6srs (3%/1 mm), and 99.80% ± 0.32% (0.83% CL) for 6x (3%/3 mm). For Millennium MLC machines, film passing rates were 98.20% ± 3.14% (7.96% CL), 99.52% ± 1.14% (2.71% CL), and 99.69% ± 0.82% (1.91% CL) for 6FFF, 6x, and 10x, respectively. For SDC to AAA comparisons: HD MLC Linear Accelerators (LINACs); DVH point agreement was 0.97% ± 1.64% (4.18% CL) and 1.05% ± 2.12% (5.20% CL); 3D gamma agreement was 99.97% ± 0.14% (0.30% CL) and 100.00% ± 0.02% (0.05% CL), for 6FFF/6srs and 6x, respectively; Millennium MLC LINACs: DVH point agreement was 0.77% ± 2.40% (5.47% CL), 0.80% ± 3.40% (7.47% CL), and 0.07% ± 2.15% (4.30% CL); 3D gamma agreement was 99.97% ± 0.13% (0.29% CL), 99.97% ± 0.17% (0.36% CL), and 99.99% ± 0.06% (0.12% CL) for 6FFF, 6x, and 10x, respectively. Conclusion SDC shows agreement well within TG119 CLs for film and redundant dose calculation comparisons with AAA. In some models (SRS), this was achieved using stricter criteria. TG119 plans can be used to help guide model adjustments and to establish clinical baselines for DVH and 3D gamma criteria.
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Affiliation(s)
| | | | | | - Anant Gopal
- Henry Ford Health System, Detroit, Michigan, USA
| | - Ning Wen
- Henry Ford Health System, Detroit, Michigan, USA
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Feygelman V, Latifi K, Bowers M, Greco K, Moros EG, Isacson M, Angerud A, Caudell J. Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric-modulated arc therapy planning. J Appl Clin Med Phys 2022; 23:e13572. [PMID: 35213089 PMCID: PMC9121035 DOI: 10.1002/acm2.13572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 11/13/2022] Open
Abstract
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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Affiliation(s)
- Vladimir Feygelman
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Kujtim Latifi
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Mark Bowers
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Kevin Greco
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Eduardo G Moros
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Max Isacson
- RaySearch Laboratories AB, Stockholm, Sweden
| | | | - Jimmy Caudell
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
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10
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Li Q, Luo H, Liu X, Zhong M, Yang H, Tao D, Jin F. Evaluation of plan quality based on a novel plan difficulty index and its preliminary application in radiotherapy. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2021. [DOI: 10.1080/16878507.2021.1988818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Qicheng Li
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Huanli Luo
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Xianfeng Liu
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Mingsong Zhong
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Han Yang
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Dan Tao
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
| | - Fu Jin
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing,China
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11
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Anetai Y, Koike Y, Takegawa H, Nakamura S, Tanigawa N. Evaluation approach for whole dose distribution in clinical cases using spherical projection and spherical harmonics expansion: spherical coefficient tensor and score method. JOURNAL OF RADIATION RESEARCH 2021:rrab081. [PMID: 34590126 DOI: 10.1093/jrr/rrab081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Whole dose distribution results from well-conceived treatment plans including patient-specific (location, size and shape of tumor, etc.) and facility-specific (clinical policy and goal, equipment, etc.) information. To evaluate the whole dose distribution efficiently and effectively, we propose a method to apply spherical projection and real spherical harmonics (SH) expansion, thus leading to the expanded coefficients as a rank-2 tensor, SH coefficient tensor, for every patient-specific dose distribution. To verify the feature of this tensor, we introduce Isomap from the manifold learning method and multi-dimensional scaling (MDS). Subsequently, we obtained the MDS distance representing similarity, η, and the SH score, ζ, which is a Frobenius norm of the SH coefficient tensor. These were then validated in the intensity-modulated radiation therapy (IMRT) data sets of: (i) 375 mixing treated regions, (ii) 135 head and neck (HN), and (iii) 132 prostate cases, respectively. The MDS map indicated that the SH coefficient tensor enabled a quantitative feature extraction of whole dose distributions. In particular, the SH score systematically detected irregular cases as the deviation higher than +1.5 standard deviations (SD) from the average case, which matched up with clinically irregular case that required very complicated dose distributions. In summary, the proposed SH coefficient tensor is a useful representation of the whole dose distribution. The SH score from the SH coefficient tensor is a convenient and simple criterion used to characterize the entire dose distributions, which is not dependent on the data set.
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Affiliation(s)
- Yusuke Anetai
- Department of Radiology, Kansai Medical University, Shin-machi 2-5-1, Hirakata-shi, Osaka 573-0101, Japan
| | - Yuhei Koike
- Department of Radiology, Kansai Medical University, Shin-machi 2-5-1, Hirakata-shi, Osaka 573-0101, Japan
| | - Hideki Takegawa
- Department of Radiology, Kansai Medical University, Shin-machi 2-5-1, Hirakata-shi, Osaka 573-0101, Japan
| | - Satoaki Nakamura
- Department of Radiology, Kansai Medical University, Shin-machi 2-5-1, Hirakata-shi, Osaka 573-0101, Japan
| | - Noboru Tanigawa
- Department of Radiology, Kansai Medical University, Shin-machi 2-5-1, Hirakata-shi, Osaka 573-0101, Japan
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12
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Stanley DN, Covington EL, Liu H, Alexandrian AN, Cardan RA, Bridges DS, Thomas EM, Fiveash JB, Popple RA. Accuracy of dose-volume metric calculation for small-volume radiosurgery targets. Med Phys 2021; 48:1461-1468. [PMID: 33294990 PMCID: PMC8248418 DOI: 10.1002/mp.14645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/18/2020] [Accepted: 11/26/2020] [Indexed: 11/10/2022] Open
Abstract
PURPOSE For stereotactic radiosurgery (SRS), accurate evaluation of dose-volume metrics for small structures is necessary. The purpose of this study was to compare the DVH metric capabilities of five commercially available SRS DVH analysis tools (Eclipse, Elements, Raystation, MIM, and Velocity). METHODS DICOM RTdose and RTstructure set files created using MATLAB were imported and evaluated in each of the tools. Each structure set consisted of 50 randomly placed spherical targets. The dose distributions were created on a 1-mm grid using an analytic model such that the dose-volume metrics of the spheres were known. Structure sets were created for 3, 5, 7, 10, 15, and 20 mm diameter spheres. The reported structure volume, V100% [cc], and V50% [cc], and the RTOG conformity index and Paddick Gradient Index, were compared with the analytical values. RESULTS The average difference and range across all evaluated target sizes for the reported structure volume was - 4.73%[-33.2,0.2], 0.11%[-10.9, 9.5], -0.39%[-12.1, 7.0], -2.24%[-21.0, 1.3], and 1.15%[-15.1,0.8], for TPS-A through TPS-E, respectively. The average difference and range for the V100%[cc] (V20Gy[cc]) was - 0.4[-24.5,9.8], -2.73[-23.6, 1.1], -3.01[-23.6, 0.6], -3.79[-27.3, 1.3], and 0.26[-6.1,2.6] for TPS-A through TPS-E, respectively. For V50%[cc](V10Gy[cc]) in TPS-A through TPS-E the average and ranger were - 0.05[-0.8,0.4], -0.18[-1.2, 0.5], -0.44[-1.4, 0.3], -0.26[-1.8, 2.6], and 0.09[-1.4,2.7]. CONCLUSION This study expanded on the previously published literature to quantitatively compare the DVH analysis capabilities of software commonly used for SRS plan evaluation and provides freely available and downloadable analytically derived set of ground truth DICOM dose and structure files for the use of radiotherapy clinics. The differences between systems highlight the need for standardization and/or transparency between systems, especially when evaluating plan quality for multi-institutional clinical trials.
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Affiliation(s)
- Dennis N Stanley
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Elizabeth L Covington
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Haisong Liu
- Department of Radiation Oncology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ara N Alexandrian
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Radiation Oncology, University of Washington, Seattle, WA, USA
| | - Rex A Cardan
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel S Bridges
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Evan M Thomas
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John B Fiveash
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Richard A Popple
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
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13
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Using fuzzy logics to determine optimal oversampling factor for voxelizing 3D surfaces in radiation therapy. Soft comput 2020. [DOI: 10.1007/s00500-020-05126-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Taylor T, Richmond N. A UK wide study of current prostate planning practice. Br J Radiol 2020; 93:20200142. [DOI: 10.1259/bjr.20200142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Objectives: The objective of this work was to undertake a non-judgemental study of prostate planning practice across the UK by inviting all departments to undertake the same case. Methods: An invitation to take part in the study was sent to the Heads of all UK radiotherapy departments and posted on the UK Medical Physics mailbase. Individuals interested in participating were able to access a single anonymised CT dataset for download with the prostate gland, seminal vesicles, bladder, rectum, bowel, femoral heads, and penile bulb outlined. A brief patient history was also supplied. Participants were asked to create planning target volumes (PTVs) according to their local clinical protocol and plan to give 60 Gy in 20 fractions to the PTV receiving the highest dose. No guidance was given for acceptable organ at risk doses. Dicom plan and dose information was loaded back into ProKnow for analysis by contributors. Results: There were 102 plan submissions made to the study representing 48 different UK radiotherapy departments. Seventeen distinct methodologies for creating the prescription PTV from the prostate and seminal vesicles were identified with the ethos of the CHHIP trial protocol for margin growing followed in nearly two-thirds of cases. Positive correlations were found when assessing the doses received by the bladder and rectum against the volume of the PTV to which 60 Gy was prescribed. Conclusions: A national planning study whereby staff from a multitude of radiotherapy departments create plans based solely on a single dataset is feasible. The cohort of data was made available to all participants following the study to enable self-assessment and benchmarking against that of their peers. Advances in knowledge: This is the first UK wide treatment planning study to investigate local clinical prostate planning practice. This has given UK departments the opportunity to evaluate their planning practices against those of their peers.
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Affiliation(s)
- Timothy Taylor
- Department of Medical Physics & Bioengineering, Royal United Hospitals Bath NHS Foundation Trust, Combe Park, Bath, BA1 3NG
| | - Neil Richmond
- Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne, NE7 7DN
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15
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Moghanaki D, Slotman B, Swaminath A, Nelms B, Wang B. Assessing the Variability and Quality of Lung Stereotactic Radiation Therapy Treatment Plans Using a Web-Based Crowdsourcing Platform. Pract Radiat Oncol 2019; 10:e118-e127. [PMID: 31837477 DOI: 10.1016/j.prro.2019.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 11/25/2019] [Accepted: 12/03/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE The quality of stereotactic body radiation therapy (SBRT) treatment plans for early stage lung cancer are unknown outside of peer-reviewed publications. Thus, a study was conducted to crowdsource and analyze a variety of lung SBRT treatment plans from around the world. METHODS AND MATERIALS This study had 2 parts, planning and contouring, and each was facilitated by a web-based technology platform. For planning, lung SBRT planners were invited to design, score, and submit their treatment plans (prescription of 11 Gy × 5) for a centralized stage I lung cancer case using standardized images and predefined contours. Each plan was scored with 20 weighted metrics adapted from currently recruiting phase 3 lung SBRT trials. For contouring, a separate image set was used to evaluate organ-at-risk contour accuracy using Dice coefficients and a StructSure score. RESULTS For planning 227 plans were submitted in total with 7 different treatment planning systems and 7 different delivery methods represented. Variability was primarily user driven and not associated with the treatment planning system, delivery modality, total monitor units, or estimated beam-on time. Many of the highest-quality plans required the shortest amount of time to deliver, independent of the delivery technique. For contouring, organ-at-risk contours were frequently over- or undercontoured and often included only the luminal air of the trachea, proximal bronchial tree, and esophagus, even when the mucosal linings were within a few centimeters of the target tumor. CONCLUSIONS These findings demonstrate the importance of quality assurance to help improve planning and contouring and the value of peer review and comparison. More readily accessible quality evaluation software solutions, such as the one used herein, may help meet this growing need.
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Affiliation(s)
- Drew Moghanaki
- Department of Radiation Oncology, Atlanta VA Health Care System, Emory University School of Medicine, Atlanta, Georgia.
| | - Berend Slotman
- Department of Radiation Oncology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | | | | | - Brian Wang
- Department of Radiation Oncology, Yale School of Medicine, New Haven, Connecticut
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16
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Liu H, Thomas EM, Li J, Yu Y, Andrews D, Markert JM, Fiveash JB, Shi W, Popple RA. Interinstitutional Plan Quality Assessment of 2 Linac-Based, Single-Isocenter, Multiple Metastasis Radiosurgery Techniques. Adv Radiat Oncol 2019; 5:1051-1060. [PMID: 33089021 PMCID: PMC7560574 DOI: 10.1016/j.adro.2019.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 10/28/2019] [Indexed: 12/05/2022] Open
Abstract
Purpose Interest and application of stereotactic radiosurgery for multiple brain metastases continue to increase. Various planning systems are available for linear accelerator (linac)–based single-isocenter multiple metastasis radiosurgery. Two of the most advanced systems are BrainLAB Multiple Metastases Elements (MME), a dynamic conformal arc (DCA) approach, and Varian RapidArc (RA), a volumetric modulated arc therapy (VMAT) approach. In this work, we systematically compared plan quality between the 2 techniques. Methods and Materials Thirty patients with 4 to 10 metastases (217 total; median 7.5; Vmin = 0.014 cm3; Vmax = 17.73 cm3) were planned with both Varian RA and MME at 2 different institutions with extensive experience in each respective technique. All plans had a single isocenter and used Varian linac equipped with high-definition multileaf collimator. RA plans used 2 to 4 noncoplanar VMAT arcs with 10 MV flattening filter-free beam. MME plans used 4 to 9 noncoplanar DCAs and 6 MV flattening filter-free beam, (minimum planning target volume [PTVmin] = 0.49 cm3; PTVmax = 27.32 cm3; PTVmedian = 7.05 cm3). Prescriptions were 14 to 24 Gy in a single fraction. Target coverage goal was 99% of volume receiving prescription dose (D99% ≥ 100%). Plans were evaluated by Radiation Therapy Oncology Group/Paddick conformity index (CI) score, 12 Gy volume (V12Gy), V8Gy, V5Gy, mean brain dose (Dmean), and beam-on time. Results Conformity was favorable among RA plans (median: MME CIRTOG = 1.38; RA CIRTOG = 1.21; P < .0001). V12Gy and V8Gy were lower for RA plans (median: MME V12 = 23.7 cm3; RA V12 = 19.2 cm3; P = .0001; median: MME V8Gy = 53.6 cm3; RA V8Gy = 44.1 cm3; P = .024). V5Gy was lower for MME plans (median: MME V5Gy = 141.4 cm3; RA V5Gy = 142.8 cm3; P = .009). Mean brain was lower for MME plans (median: MME Dmean = 2.57 Gy; RA Dmean = 2.76 Gy; P < .0001). Conclusions For linac-based multiple metastasis stereotactic radiosurgery, RapidArc VMAT facilitates favorable conformity and V12Gy/V8Gy volume compared with the MME DCA plan. MME planning facilitates reduced dose spill at levels ≤V5Gy.
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Affiliation(s)
- Haisong Liu
- Department of Radiation Oncology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Evan M Thomas
- Department of Radiation Oncology, University of Alabama at Birmingham, Comprehensive Cancer Center, Birmingham, Alabama
| | - Jun Li
- Department of Radiation Oncology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Yan Yu
- Department of Radiation Oncology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - David Andrews
- Department of Neurosurgery, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - James M Markert
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - John B Fiveash
- Department of Radiation Oncology, University of Alabama at Birmingham, Comprehensive Cancer Center, Birmingham, Alabama
| | - Wenyin Shi
- Department of Radiation Oncology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Richard A Popple
- Department of Radiation Oncology, University of Alabama at Birmingham, Comprehensive Cancer Center, Birmingham, Alabama
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17
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van der Meer MC, Bosman PAN, Pieters BR, Niatsetski Y, van Wieringen N, Alderliesten T, Bel A. Sensitivity of dose-volume indices to computation settings in high-dose-rate prostate brachytherapy treatment plan evaluation. J Appl Clin Med Phys 2019; 20:66-74. [PMID: 30882986 PMCID: PMC6448172 DOI: 10.1002/acm2.12563] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/13/2019] [Accepted: 02/16/2019] [Indexed: 11/11/2022] Open
Abstract
Purpose To investigate the variation in computed dose‐volume (DV) indices for high‐dose‐rate (HDR) prostate brachytherapy that can result from typical differences in computation settings in treatment planning systems (TPSs). Methods Five factors were taken into account: number of dose‐calculation points, radioactive source description, interpolation between delineated contours, intersections between delineated organ contours, and organ shape at the top and bottom contour using either full or partial slice thickness. Using in‐house developed software, the DV indices of the treatment plans of 26 patients were calculated with different settings, and compared to a baseline setting that closely followed the default settings of the TPS used in our medical center. Studied organs were prostate and seminal vesicles, denoted as targets, and bladder, rectum, and urethra, denoted as organs at risk (OARs), which were delineated on MRI scans with a 3.3 mm slice thickness. Results When sampling a fixed number of points in each organ, in order to achieve a width of the 95% confidence interval over all patients of the DV indices of 1% or less, only 32,000 points had to be sampled per target, but 256,000 points had to be sampled per OAR. For the remaining factors, DV indices changed up to 0.4% for rectum, 1.3% for urethra, and 2.6% for prostate. DV indices of the bladder changed especially if the high‐dose‐region was (partly) located at the most caudal contour, up to 8.5%, and DV indices of the vesicles changed especially if there were few delineated contours, up to 9.8%, both due to the use of full slice thickness for the top and bottom contour. Conclusions The values of DV indices used in prostate HDR brachytherapy treatment planning are influenced by the computation settings in a TPS, especially at the most caudal part of the bladder, as well as in the seminal vesicles.
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Affiliation(s)
- Marjolein C van der Meer
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Peter A N Bosman
- Life Sciences and Health Research Group, Centrum Wiskunde & Informatica, Amsterdam, the Netherlands.,Algorithmics Group, Department of Software Technology, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, the Netherlands
| | - Bradley R Pieters
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Yury Niatsetski
- Physics and Advanced Development, Elekta, Veenendaal, the Netherlands
| | - Niek van Wieringen
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Tanja Alderliesten
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Arjan Bel
- Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
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18
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Leasure JM, Ulizio V, Pearson D. Retrospective dosimetric analysis of brain lesions planned in Pinnacle 9.8 via a HDMLC linac. Med Dosim 2018; 44:e8-e12. [PMID: 30274874 DOI: 10.1016/j.meddos.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/13/2018] [Accepted: 08/03/2018] [Indexed: 12/01/2022]
Abstract
The University of Toledo Medical Center's Eleanor N. Dana Cancer Center located in northwest Ohio currently utilizes the Edge Radiosurgery System (Varian Medical Systems Inc., Palo Alto, CA) to deliver stereotactic radiosurgery for the treatment of brain lesions. The purpose of this study is to determine the quality of conformal arc radiotherapy in treating patients with brain lesions at The University of Toledo Medical Center and to provide more data for conformity and gradient indices (due to a lack of current data) to hopefully improve national standards by allowing centers to compare among each other. Treatment plans were assessed using the Pinnacle3 v9.8 Radiation Therapy Planning System (Philips Healthcare, Amsterdam, Netherlands). For patients (n = 41) presenting with small brain lesions (n = 82) and treated with conformal arc radiotherapy via the Edge Radiosurgery System, the RTOG conformity index, Paddick conformity index, conformity gradient index, gradient index, and dose gradient index were determined for each plan. This study additionally provides data to suggest the more accurate method of volume derivation provided by the Pinnacle3 v9.8 software. Using this method, average values for each of the following indices were calculated: RTOG conformity index = 1.36 ± 0.29; Paddick conformity index = 0.72 ± 0.12; conformity gradient index = 214.67 ± 12.35; gradient index = 3.64 ± 1.09; dose gradient index = -0.11 ± 0.16. Thus, The University of Toledo Medical Center provides favorable conformity of dose to intracranial target lesions.
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Affiliation(s)
| | - Vincent Ulizio
- University of Toledo, Radiation Oncology, Toledo, OH, USA.
| | - David Pearson
- University of Toledo, Radiation Oncology, Toledo, OH, USA
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Nelms B, Stambaugh C, Hunt D, Tonner B, Zhang G, Feygelman V. Methods, software and datasets to verify DVH calculations against analytical values: Twenty years late(r). Med Phys 2016; 42:4435-48. [PMID: 26233174 DOI: 10.1118/1.4923175] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The authors designed data, methods, and metrics that can serve as a standard, independent of any software package, to evaluate dose-volume histogram (DVH) calculation accuracy and detect limitations. The authors use simple geometrical objects at different orientations combined with dose grids of varying spatial resolution with linear 1D dose gradients; when combined, ground truth DVH curves can be calculated analytically in closed form to serve as the absolute standards. METHODS dicom RT structure sets containing a small sphere, cylinder, and cone were created programmatically with axial plane spacing varying from 0.2 to 3 mm. Cylinders and cones were modeled in two different orientations with respect to the IEC 1217 Y axis. The contours were designed to stringently but methodically test voxelation methods required for DVH. Synthetic RT dose files were generated with 1D linear dose gradient and with grid resolution varying from 0.4 to 3 mm. Two commercial DVH algorithms-pinnacle (Philips Radiation Oncology Systems) and PlanIQ (Sun Nuclear Corp.)-were tested against analytical values using custom, noncommercial analysis software. In Test 1, axial contour spacing was constant at 0.2 mm while dose grid resolution varied. In Tests 2 and 3, the dose grid resolution was matched to varying subsampled axial contours with spacing of 1, 2, and 3 mm, and difference analysis and metrics were employed: (1) histograms of the accuracy of various DVH parameters (total volume, Dmax, Dmin, and doses to % volume: D99, D95, D5, D1, D0.03 cm(3)) and (2) volume errors extracted along the DVH curves were generated and summarized in tabular and graphical forms. RESULTS In Test 1, pinnacle produced 52 deviations (15%) while PlanIQ produced 5 (1.5%). In Test 2, pinnacle and PlanIQ differed from analytical by >3% in 93 (36%) and 18 (7%) times, respectively. Excluding Dmin and Dmax as least clinically relevant would result in 32 (15%) vs 5 (2%) scored deviations for pinnacle vs PlanIQ in Test 1, while Test 2 would yield 53 (25%) vs 17 (8%). In Test 3, statistical analyses of volume errors extracted continuously along the curves show pinnacle to have more errors and higher variability (relative to PlanIQ), primarily due to pinnacle's lack of sufficient 3D grid supersampling. Another major driver for pinnacle errors is an inconsistency in implementation of the "end-capping"; the additional volume resulting from expanding superior and inferior contours halfway to the next slice is included in the total volume calculation, but dose voxels in this expanded volume are excluded from the DVH. PlanIQ had fewer deviations, and most were associated with a rotated cylinder modeled by rectangular axial contours; for coarser axial spacing, the limited number of cross-sectional rectangles hinders the ability to render the true structure volume. CONCLUSIONS The method is applicable to any DVH-calculating software capable of importing dicom RT structure set and dose objects (the authors' examples are available for download). It includes a collection of tests that probe the design of the DVH algorithm, measure its accuracy, and identify failure modes. Merits and applicability of each test are discussed.
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Affiliation(s)
| | | | - Dylan Hunt
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612
| | - Brian Tonner
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612
| | - Geoffrey Zhang
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612
| | - Vladimir Feygelman
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612
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