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Malhotra A, Carpentier EE, Duzenli C. Recommendations for using analytical anisotropic algorithm and AcurosXB for epidermal dose calculations in breast radiotherapy from an in vivo Gafchromic film study. J Appl Clin Med Phys 2024; 25:e14416. [PMID: 38812120 PMCID: PMC11302804 DOI: 10.1002/acm2.14416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/27/2024] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND AND PURPOSE This study recommends clinical epidermal dose calculation methods based on in-vivo film measurements and registered skin dose distributions with the Eclipse (Varian Medical Systems) treatment planning system's Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB) dose calculation algorithms. MATERIALS AND METHODS Eighteen AAA V13.6 breast plans were recalculated using AXB (dose to medium) V13.5 with the same beam parameters and monitor units as in the original plans. These are compared against in-vivo Gafchromic film measurements from the lateral and inferior breast regions. Three skin structures in the treatment planning system are evaluated: a surface layer of voxels of the body contour, a 0.2 cm internal skin rind, and a 0.5 cm internal skin rind. RESULTS Systematic shifts are demonstrated between the film measurements of skin dose and the Eclipse dose calculations. On average, the dose to the surface layer of pixels is underestimated by AAA by 8% and overestimated by AXB by 3%. A 5 mm skin rind extended into the body can increase epidermal dose calculations on average by 8% for AAA and 4% for AXB. CONCLUSION This is the first study to register in-vivo skin dose distributions in the breast to the treatment planning system for comparison. Based on the results from this study it is recommended that epidermal dose is calculated with a 0.5 cm skin rind for the AAA algorithm and with rind thickness up to 0.2 cm for the AXB algorithm.
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Affiliation(s)
- Aria Malhotra
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Emilie E. Carpentier
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Cheryl Duzenli
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of SurgeryDivision of Radiation Oncology and Experimental RadiotherapeuticsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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Kayal G, Van B, Andl G, Tu C, Wareing T, Wilderman S, Mikell J, Dewaraja YK. Linear Boltzmann equation solver for voxel-level dosimetry in radiopharmaceutical therapy: Comparison with Monte Carlo and kernel convolution. Med Phys 2024; 51:5604-5617. [PMID: 38436493 PMCID: PMC11321934 DOI: 10.1002/mp.16996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 01/12/2024] [Accepted: 01/28/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND With recent interest in patient-specific dosimetry for radiopharmaceutical therapy (RPT) and selective internal radiation therapy (SIRT), an increasing number of voxel-based algorithms are being evaluated. Monte Carlo (MC) radiation transport, generally considered to be the most accurate among different methods for voxel-level absorbed dose estimation, can be computationally inefficient for routine clinical use. PURPOSE This work demonstrates a recently implemented grid-based linear Boltzmann transport equation (LBTE) solver for fast and accurate voxel-based dosimetry in RPT and SIRT and benchmarks it against MC. METHODS A deterministic LBTE solver (Acuros MRT) was implemented within a commercial RPT dosimetry package (Velocity 4.1). The LBTE is directly discretized using an adaptive mesh refined grid and then the coupled photon-electron radiation transport is iteratively solved inside specified volumes to estimate radiation doses from both photons and charged particles in heterogeneous media. To evaluate the performance of the LBTE solver for RPT and SIRT applications, 177Lu SPECT/CT, 90Y PET/CT, and 131I SPECT/CT images of phantoms and patients were used. Multiple lesions (2-1052 mL) and normal organs were delineated for each study. Voxel dosimetry was performed with the LBTE solver, dose voxel kernel (DVK) convolution with density correction, and a validated in-house MC code using the same time-integrated activity and density maps as input to the different dose engines. The resulting dose maps, difference maps, and dose-volume-histogram (DVH) metrics were compared, to assess the voxel-level agreement. Evaluation of mean absorbed dose included comparison with structure-level estimates from OLINDA. RESULTS In the phantom inserts/compartments, the LBTE solver versus MC and DVK convolution demonstrated good agreement with mean absorbed dose and DVH metrics agreeing to within 5% except for the D90 and D70 metrics of a very low activity concentration insert of 90Y where the agreement was within 15%. In the patient studies (five patients imaged after 177Lu DOTATATE RPT, five after 90Y SIRT, and two after 131I radioimmunotherapy), in general, there was better agreement between the LBTE solver and MC than between LBTE solver and DVK convolution for mean absorbed dose and voxel-level evaluations. Across all patients for all three radionuclides, for soft tissue structures (kidney, liver, lesions), the mean absorbed dose estimates from the LBTE solver were in good agreement with those from MC (median difference < 1%, maximum 9%) and those from DVK (median difference < 5%, maximum 9%). The LBTE and OLINDA estimates for mean absorbed dose in kidneys and liver agreed to within 10%, but differences for lesions were larger with a maximum 14% for 177Lu, 23% for 90Y, and 26% for 131I. For bone regions, the agreement in mean absorbed doses between LBTE and both MC and DVK were similar (median < 11%, max 11%) while for lung the agreement between LBTE and MC (median < 1%, max 8%) was substantially better than between LBTE and DVK (median < 16%, max 33%). Voxel level estimates for soft tissue structures also showed good agreement between the LBTE solver and both MC and DVK with a median difference < 5% (maximum < 13%) for the DVH metrics with all three radionuclides. The largest difference in DVH metrics was for the D90 and D70 metric in lung and bone where the uptake was low. Here, the difference between LBTE and MC had a median value < 14% (maximum 23%) for bone and < 4% (maximum 37%) for lung, while the corresponding differences between LBTE and DVK were < 23% (maximum 31%) and < 67% (maximum 313%), respectively. For a typical patient with a matrix size of 166 × 166 × 129 (voxel size 3 × 3 × 3 mm3), voxel dosimetry using the LBTE solver was as fast as ∼2 min on a desktop computer. CONCLUSION Having established good agreement between the LBTE solver and MC for RPT and SIRT applications, the LBTE solver is a viable option for voxel dosimetry that can be faster than MC. Further analysis is being performed to encompass the broad range of radionuclides and conditions encountered clinically.
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Affiliation(s)
- Gunjan Kayal
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin Van
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - George Andl
- Varian Medical Systems, Atlanta, Georgia, USA
| | - Cheng Tu
- Varian Medical Systems, Atlanta, Georgia, USA
| | | | - Scott Wilderman
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Justin Mikell
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - Yuni K. Dewaraja
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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Adam DP, Grudzinski JJ, Marsh IR, Hill PM, Cho SY, Bradshaw TJ, Longcor J, Burr A, Bruce JY, Harari PM, Bednarz BP. Voxel-Level Dosimetry for Combined Iodine 131 Radiopharmaceutical Therapy and External Beam Radiation Therapy Treatment Paradigms for Head and Neck Cancer. Int J Radiat Oncol Biol Phys 2024; 119:1275-1284. [PMID: 38367914 DOI: 10.1016/j.ijrobp.2024.02.005] [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: 08/15/2023] [Revised: 12/20/2023] [Accepted: 02/08/2024] [Indexed: 02/19/2024]
Abstract
PURPOSE Targeted radiopharmaceutical therapy (RPT) in combination with external beam radiation therapy (EBRT) shows promise as a method to increase tumor control and mitigate potential high-grade toxicities associated with re-treatment for patients with recurrent head and neck cancer. This work establishes a patient-specific dosimetry framework that combines Monte Carlo-based dosimetry from the 2 radiation modalities at the voxel level using deformable image registration (DIR) and radiobiological constructs for patients enrolled in a phase 1 clinical trial combining EBRT and RPT. METHODS AND MATERIALS Serial single-photon emission computed tomography (SPECT)/computed tomography (CT) patient scans were performed at approximately 24, 48, 72, and 168 hours postinjection of 577.2 MBq/m2 (15.6 mCi/m2) CLR 131, an iodine 131-containing RPT agent. Using RayStation, clinical EBRT treatment plans were created with a treatment planning CT (TPCT). SPECT/CT images were deformably registered to the TPCT using the Elastix DIR module in 3D Slicer software and assessed by measuring mean activity concentrations and absorbed doses. Monte Carlo EBRT dosimetry was computed using EGSnrc. RPT dosimetry was conducted using RAPID, a GEANT4-based RPT dosimetry platform. Radiobiological metrics (biologically effective dose and equivalent dose in 2-Gy fractions) were used to combine the 2 radiation modalities. RESULTS The DIR method provided good agreement for the activity concentrations and calculated absorbed dose in the tumor volumes for the SPECT/CT and TPCT images, with a maximum mean absorbed dose difference of -11.2%. Based on the RPT absorbed dose calculations, 2 to 4 EBRT fractions were removed from patient EBRT treatments. For the combined treatment, the absorbed dose to target volumes ranged from 57.14 to 75.02 Gy. When partial volume corrections were included, the mean equivalent dose in 2-Gy fractions to the planning target volume from EBRT + RPT differed -3.11% to 1.40% compared with EBRT alone. CONCLUSIONS This work demonstrates the clinical feasibility of performing combined EBRT + RPT dosimetry on TPCT scans. Dosimetry guides treatment decisions for EBRT, and this work provides a bridge for the same paradigm to be implemented within the rapidly emerging clinical RPT space.
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Affiliation(s)
- David P Adam
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joseph J Grudzinski
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Ian R Marsh
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Patrick M Hill
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Steve Y Cho
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Tyler J Bradshaw
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | | | - Adam Burr
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Justine Y Bruce
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin; Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Paul M Harari
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Bryan P Bednarz
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin.
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Lincoln J, MacDonald L, Ward L, Johnston S, Syme A, Thomas C. Serial and parallel organ-at-risk-specific noncoplanar arc optimization for small versus large target volumes in liver SBRT. J Appl Clin Med Phys 2024:e14396. [PMID: 38894588 DOI: 10.1002/acm2.14396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 04/10/2024] [Accepted: 04/23/2024] [Indexed: 06/21/2024] Open
Abstract
Noncoplanar arc optimization has been shown to reduce OAR doses in SRS/SRT and has the potential to reduce doses to OARs in SBRT. Extracranial targets have additional considerations, including large OARs and, in the case of the liver, volume constraints on the healthy liver. Considering pathlengths through OARs that encompass target volumes may lead to specific dose reductions as in the encompassing healthy liver tissue. These optimizations must also leverage delivery efficiency and trajectory sampling to ensure ease of clinical translation. The purpose of this research is to generate optimized static-couch arcs that separately consider serial and parallel OARs and arc delivery efficiency, with a trajectory sampling metric, towards the aim of reducing dose to OARs and the surrounding healthy liver tissue. Separate BEV cost maps were created for parallel, and serial OARs by means of a fast ray-triangle intersection algorithm. An additional BEV cost map was created for the liver which, by definition, encompasses the liver tumors. The individual costs of these maps were summed and combined with the sampling metric for 100 000 random combinations of arc trajectories. A search algorithm was applied to find an arc trajectory solution that satisfied BEV cost and sampling optimization, while also ensuring an efficient delivery was possible with a low number of arcs. This method of arc selection was evaluated for 16 liver SBRT patients characterized by small and large target volumes. Comparisons were made with a clinical arc template of coplanar arcs. Dosimetric plan quality was evaluated using published guidelines and metrics from RTOG1112. Four of five plan quality metrics for the liver were significantly reduced when planned with optimized noncoplanar arcs. Median (range) reductions of the volumes receiving 10, 18, and 21 Gy were found of 140.4 (295.8) cc (p = 0.001), 28.2 (230.6) cc (p = 0.002) and 18.5 (155.5) cc (p = 0.04). A significant increase in median (range) dose to the right kidney of 0.2 ± 0.9 Gy (p = 0.03) was also found using optimized noncoplanar arcs, which was below the tolerance of 10 Gy for all cases. The average number of arcs chosen was 4 ± 1. Optimizing serial and parallel OARs separately during static couch noncoplanar arc selection significantly reduced the dose to the liver during SBRT using a moderate number of arcs.
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Affiliation(s)
- John Lincoln
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada
| | - Lee MacDonald
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada
- Department of Radiation Oncology, Dalhousie University, Halifax, Canada
- Department of Medical Physics, Nova Scotia Health, Halifax, Canada
| | - Lucy Ward
- Department of Radiation Oncology, Dalhousie University, Halifax, Canada
| | - Shelly Johnston
- Department of Radiation Oncology, Dalhousie University, Halifax, Canada
| | - Alasdair Syme
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada
- Department of Radiation Oncology, Dalhousie University, Halifax, Canada
- Department of Medical Physics, Nova Scotia Health, Halifax, Canada
| | - Christopher Thomas
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada
- Department of Radiation Oncology, Dalhousie University, Halifax, Canada
- Department of Medical Physics, Nova Scotia Health, Halifax, Canada
- Department of Radiology, Dalhousie University, Halifax, Canada
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Kosaka T, Takatsu J, Inoue T, Iijima K, Suzuki M, Murakami N, Shikama N. Dosimetric evaluation in Helical TomoTherapy for lung SBRT using Monte Carlo-based independent dose verification software. J Appl Clin Med Phys 2024; 25:e14305. [PMID: 38368607 PMCID: PMC11087163 DOI: 10.1002/acm2.14305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/24/2024] [Accepted: 02/05/2024] [Indexed: 02/20/2024] Open
Abstract
PURPOSE To elucidate the dosimetric errors caused by a model-based algorithm in lung stereotactic body radiation therapy (SBRT) with Helical TomoTherapy (HT) using Monte Carlo (MC)-based dose verification software. METHODS For 38 plans of lung SBRT, the dose calculation accuracy of a treatment planning system (TPS) of HT was compared with the results of DoseCHECK, the commercial MC-based independent verification software. The following indices were extracted to evaluate the correlation of dosimetric errors: (1) target volume, (2) average computed tomography (CT) value of the planning target volume (PTV) margin, and (3) average CT value of surrounding 2-mm area of the PTV (PTV ring). Receiver operating characteristic (ROC) analyses determined the threshold for 5% of differences in PTV D95%. Then, the 38 plans were classified into two groups using the cutoff values of ROC analysis for these three indices. Dosimetric differences between groups were statistically compared using the Mann-Whitney U test. RESULTS TPS of HT overestimated by more than 5% in the PTV D95% in 16 of 38 plans. The PTV ring showed the strongest correlation with dosimetric differences. The cutoff value for the target volume, the PTV margin, and the PTV ring was 14.7 cc, -754 HU, and -708 HU, respectively. The area under the curve (AUC) for the target volume, the PTV margin, and the PTV ring were 0.835, 0.878, and 0.932, respectively. Dosimetric errors more than 5% were observed when the PTV volume was less than 15 cc or when the CT value around the target was less than -700 HU. CONCLUSION The TPS of HT might overestimate the PTV dose by more than 5% if any the three indices in this study were below threshold. Therefore, independent verification with an MC-based algorithm should be strongly recommended for lung SBRT in HT.
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Affiliation(s)
- Takahiro Kosaka
- Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
- Department of Radiology, Juntendo University Urayasu Hospital, Urayasu-shi, Chiba, Japan
| | - Jun Takatsu
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Tatsuya Inoue
- Department of Radiology, Juntendo University Urayasu Hospital, Urayasu-shi, Chiba, Japan
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Kotaro Iijima
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Michimasa Suzuki
- Department of Radiology, Juntendo University Urayasu Hospital, Urayasu-shi, Chiba, Japan
| | - Naoya Murakami
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Naoto Shikama
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
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Callens D, Aerts K, Berkovic P, Vandewinckele L, Lambrecht M, Crijns W. Are offline ART decisions for NSCLC impacted by the type of dose calculation algorithm? Tech Innov Patient Support Radiat Oncol 2024; 29:100236. [PMID: 38313556 PMCID: PMC10835600 DOI: 10.1016/j.tipsro.2024.100236] [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: 08/18/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 02/06/2024] Open
Abstract
Introduction Decisions for plan-adaptations may be impacted by a transitioning from one dose-calculation algorithm to another. This study examines the impact on dosimetric-triggered offline adaptation in LA-NSCLC in the context of a transition from superposition/convolution dose calculation algorithm (Type-B) to linear Boltzmann equation solver dose calculation algorithms (Type-C). Materials & Methods Two dosimetric-triggered offline adaptive treatment workflows are compared in a retrospective planning study on 30 LA-NSCLC patients. One workflow uses a Type-B dose calculation algorithm and the other uses Type-C. Treatment plans were re-calculated on the anatomy of a mid-treatment synthetic-CT utilizing the same algorithm utilized for pre-treatment planning. Assessment for plan-adaptation was evaluated through a decision model based on target coverage and OAR constraint violation. The impact of algorithm during treatment planning was controlled for by recalculating the Type-B plan with Type-C. Results In the Type-B approach, 13 patients required adaptation due to OAR-constraint violations, while 15 patients required adaptation in the Type-C approach. For 8 out of 30 cases, the decision to adapt was opposite in both approaches. None of the patients in our dataset encountered CTV-target underdosage that necessitated plan-adaptation. Upon recalculating the Type-B approach with the Type-C algorithm, it was shown that 10 of the original Type-B plans revealed clinically relevant dose reductions (≥3%) on the CTV in their original plans. This re-calculation identified 21 plans in total that required ART. Discussion In our study, nearly one-third of the cases would have a different decision for plan-adaption when utilizing Type-C instead of Type-B. There was no substantial increase in the total number of plan-adaptations for LA-NSCLC. However, Type-C is more sensitive to altered anatomy during treatment compared to Type-B. Recalculating Type-B plans with the Type-C algorithm revealed an increase from 13 to 21 cases triggering ART.
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Affiliation(s)
- Dylan Callens
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
- Department of Radiation Oncology, UZ Leuven, Leuven, Belgium
| | - Karel Aerts
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
| | - Patrick Berkovic
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
- Department of Radiation Oncology, UZ Leuven, Leuven, Belgium
| | - Liesbeth Vandewinckele
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
- Department of Radiation Oncology, UZ Leuven, Leuven, Belgium
| | - Maarten Lambrecht
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
- Department of Radiation Oncology, UZ Leuven, Leuven, Belgium
| | - Wouter Crijns
- Laboratory of Experimental Radiotherapy, KU Leuven, Leuven, Belgium
- Department of Radiation Oncology, UZ Leuven, Leuven, Belgium
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Delbaere A, Younes T, Khamphan C, Vieillevigne L. Experimental validation of absorbed dose-to-medium calculation algorithms in heterogeneous media. Phys Med Biol 2024; 69:055006. [PMID: 38266285 DOI: 10.1088/1361-6560/ad222e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/24/2024] [Indexed: 01/26/2024]
Abstract
Objective.The aim of this work was to determine heterogeneous correction factorshQclin,Qreffclin,frefdetm,wto validate absorbed dose-to-mediumDm,Qclinm,fclincalculation algorithms from detector readings. The impact of detector orientation perpendicular and parallel to the beam central axis on the correction factors was also investigated.Approach.ThehQclin,Qreffclin,frefdetm,wfactors were calculated for four types of detectors (PTW PinPoint T31016, PTW microDiamond T60019, PTW microSilicon T60023 and EBT3 film) placed in different media (cortical bone, lung, adipose tissue, Teflon and RW3) for the 6 MV energy beam with a 10 × 10 cm2field size. These corrections were then applied to the detector measurements performed at different depths in heterogeneous phantoms.Main results.ThehQclin,Qreffclin,frefdetm,wfactors mainly depended on the media and slightly on the type of detector. Considering all detectors, the largest corrections were found in high-density media with values ranging from 0.911 to 0.934 in cortical bone. For comparison, the corrections in other media were closer to unity with values from 0.966 (lung and RW3) to 0.991 (adipose tissue). Except for the PinPoint T31016, detector orientation-dependence was observed especially in high-density media. A good agreement (≤1.5%) was found betweenDm,Qclinm,fclincalculations and the detector readings corrected with thehQclin,Qreffclin,frefdetm,wfactor for all studied heterogeneous phantoms.Significance.This paper could serve as an initial guideline for medical physicists involved in the validation of the advanced type-b dose calculation algorithms reportingDm,Qclinm,fclin. To our knowledge, this is the first study to assess the impact of the orientation of different detectors in heterogeneous media. The orientation dependence of the detector response observed in water may not reflect what is observed in heterogeneous media, especially in high-density media. The knowledge of thehQclin,Qreffclin,frefdetm,wfactors becomes mandatory for accurate interpretation of detector readings and comparisons withDm,Qclinm,fclincalculations.
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Affiliation(s)
- Alexia Delbaere
- Department of Medical Physics, Oncopole Claudius Regaud - Institut Universitaire du Cancer de Toulouse, F-31059 Toulouse, France
- Centre de Recherches en Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, Oncopole, F-31037 Toulouse, France
| | - Tony Younes
- Department of Medical Physics, Oncopole Claudius Regaud - Institut Universitaire du Cancer de Toulouse, F-31059 Toulouse, France
- Centre de Recherches en Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, Oncopole, F-31037 Toulouse, France
| | - Catherine Khamphan
- Department of Medical Physics, Institut du Cancer-Avignon Provence, F-84000 Avignon, France
| | - Laure Vieillevigne
- Department of Medical Physics, Oncopole Claudius Regaud - Institut Universitaire du Cancer de Toulouse, F-31059 Toulouse, France
- Centre de Recherches en Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, Oncopole, F-31037 Toulouse, France
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Bedford JL. Inverse planning of lung radiotherapy with photon and proton beams using a discrete ordinates Boltzmann solver. Phys Med Biol 2024; 69:035021. [PMID: 38198720 DOI: 10.1088/1361-6560/ad1cf7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/10/2024] [Indexed: 01/12/2024]
Abstract
Objective. A discrete ordinates Boltzmann solver has recently been developed for use as a fast and accurate dose engine for calculation of photon and proton beams. The purpose of this study is to apply the algorithm to the inverse planning process for photons and protons and to evaluate the impact that this has on the quality of the final solution.Approach.The method was implemented into an iterative least-squares inverse planning optimiser, with the Boltzmann solver used every 20 iterations over the total of 100 iterations. Elemental dose distributions for the intensity modulation and the dose changes at the intermediate iterations were calculated by a convolution algorithm for photons and a simple analytical model for protons. The method was evaluated for 12 patients in the heterogeneous tissue environment encountered in radiotherapy of lung tumours. Photon arc and proton arc treatments were considered in this study. The results were compared with those for use of the Boltzmann solver solely at the end of inverse planning or not at all.Main results.Application of the Boltzmann solver at the end of inverse planning shows the dose heterogeneity in the planning target volume to be greater than calculated by convolution and empirical methods, with the median root-mean-square dose deviation increasing from 3.7 to 5.3 for photons and from 1.9 to 3.4 for proton arcs. Use of discrete ordinates throughout inverse planning enables homogeneity of target coverage to be maintained throughout, the median root-mean-square dose deviation being 3.6 for photons and 2.3 for protons. Dose to critical structures is similar with discrete ordinates and conventional methods. Time for inverse planning with discrete ordinates takes around 1-2 h using a contemporary computing environment.Significance.By incorporating the Boltzmann solver into an iterative least squares inverse planning optimiser, accurate dose calculation in a heterogeneous medium is obtained throughout inverse planning, with the result that the final dose distribution is of the highest quality.
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Affiliation(s)
- James L Bedford
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, United Kingdom
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Hirashima H, Nakamura M, Nakamura K, Matsuo Y, Mizowaki T. Dosimetric verification of four dose calculation algorithms for spine stereotactic body radiotherapy. JOURNAL OF RADIATION RESEARCH 2024; 65:109-118. [PMID: 37996097 PMCID: PMC10803157 DOI: 10.1093/jrr/rrad086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/18/2023] [Accepted: 10/16/2023] [Indexed: 11/25/2023]
Abstract
The applications of Type B [anisotropic analytical algorithm (AAA) and collapsed cone (CC)] and Type C [Acuros XB (AXB) and photon Monte Carlo (PMC)] dose calculation algorithms in spine stereotactic body radiotherapy (SBRT) were evaluated. Water- and bone-equivalent phantoms were combined to evaluate the percentage depth dose and dose profile. Subsequently, 48 consecutive patients with clinical spine SBRT plans were evaluated. All treatment plans were created using AXB in Eclipse. The prescription dose was 24 Gy in two fractions at a 10 MV FFF on TrueBeam. The doses were then recalculated with AAA, CC and PMC while maintaining the AXB-calculated monitor units and beam arrangement. The dose index values obtained using the four dose calculation algorithms were then compared. The AXB and PMC dose distributions agreed with the bone-equivalent phantom measurements (within ±2.0%); the AAA and CC values were higher than those in the bone-equivalent phantom region. For the spine SBRT plans, PMC, AAA and CC were overestimated compared with AXB in terms of the near minimum and maximum doses of the target and organ at risk, respectively; the mean dose difference was within 4.2%, which is equivalent with within 1 Gy. The phantom study showed that the results from AXB and PMC agreed with the measurements within ±2.0%. However, the mean dose difference ranged from 0.5 to 1 Gy in the spine SBRT planning study when the dose calculation algorithms changed. Users should incorporate a clinical introduction that includes an awareness of these differences.
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Affiliation(s)
- Hideaki Hirashima
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Department of Advanced Medical Physics, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kiyonao Nakamura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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Song H, Hu J, He J, Ma G, Cheng L, Li X. Dosimetric impact of hollow intraoral stents for head and neck cancer radiotherapy: A phantom study. J Appl Clin Med Phys 2023; 24:e14101. [PMID: 37477628 PMCID: PMC10647986 DOI: 10.1002/acm2.14101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 06/27/2023] [Accepted: 07/06/2023] [Indexed: 07/22/2023] Open
Abstract
PURPOSE To investigate the dosimetric impact of the calculation boundaries and dose calculation algorithms of radiotherapy in head and neck cancer patients with an opened oral cavity connected to the exterior by a hollow intraoral positioning stent. METHODS AND MATERIALS A homemade silicone phantom with an opened oral cavity was placed in a CIRS head phantom to model head and neck cancer patients with a hollow intraoral positioning stent. 3D-CRT plans were designed on CT images of the phantom in Monaco and Pinnacle3 treatment planning systems (TPSs) with the same beam parameters. The default boundary and manually extrapolated boundary were both adopted in these two TPSs to explore the dosimetric impact on treatment plans. The nanoDot™ optically stimulated luminescence dosimeters (OSLDs) were chosen to measure the planned dose surrounding the oral cavity of the head phantom after calibration. RESULT The doses in the air cavity and two measuring points at the joint area were dramatically changed from 0.0, 92.4 and 148.8 cGy to 177.8, 244.2 and 244.1 cGy in Monaco after adopting the extrapolated boundary. While the calculated doses at the same place were changed from 61.2, 143.7 and 198.3 cGy to 175.4, 234.7 and 233.2 cGy in Pinnacle3 with a similar calculation boundary. For the Monaco TPS, the relative errors compared to the OSLD measured doses were 2.94 ± 1.93%, 0.53 ± 8.64%, 2.65 ± 1.87% and 3.93 ± 1.69% at 4 measuring positions. In contrast, the relative errors 4.03 ± 1.93%, 4.85 ± 8.64%, 7.61 ± 1.87% and 5.61 ± 1.69% were observed in Pinnacle3 . CONCLUSION The boundary setting of an opened oral cavity in TPSs has a significant dosimetric impact on head and neck cancer radiotherapy. An extrapolated boundary should be manually set up to include the whole oral cavity in the dose calculation domain to avoid major dose deviations.
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Affiliation(s)
- Hongbing Song
- Department of RadiotherapyRenmin Hospital of Wuhan UniversityWuhanHubeiChina
| | - Jian Hu
- Department of RadiotherapyRenmin Hospital of Wuhan UniversityWuhanHubeiChina
| | - Junxiang He
- Department of RadiotherapyRenmin Hospital of Wuhan UniversityWuhanHubeiChina
| | - Guangdong Ma
- Department of RadiotherapyRenmin Hospital of Wuhan UniversityWuhanHubeiChina
| | - Lan Cheng
- Department of RadiologyUnion HospitalTongJi Medical CollegeHuazhong University of Science and TechnologyWuhanHubeiChina
| | - Xiangpan Li
- Department of RadiotherapyRenmin Hospital of Wuhan UniversityWuhanHubeiChina
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Yoon J, Jung H, Tanny SM, Lemus OMD, Milano MT, Hardy SJ, Usuki KY, Zheng D. A comprehensive evaluation of advanced dose calculation algorithms for brain stereotactic radiosurgery. J Appl Clin Med Phys 2023; 24:e14169. [PMID: 37775989 PMCID: PMC10647955 DOI: 10.1002/acm2.14169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 09/01/2023] [Accepted: 09/18/2023] [Indexed: 10/01/2023] Open
Abstract
PURPOSE Accurate dose calculation is important in both target and low dose normal tissue regions for brain stereotactic radiosurgery (SRS). In this study, we aim to evaluate the dosimetric accuracy of the two advanced dose calculation algorithms for brain SRS. METHODS Retrospective clinical case study and phantom study were performed. For the clinical study, 138 SRS patient plans (443 targets) were generated using BrainLab Elements Voxel Monte Carlo (VMC). To evaluate the dose calculation accuracy, the plans were exported into Eclipse and recalculated with Acuros XB (AXB) algorithm with identical beam parameters. The calculated dose at the target center (Dref), dose to 95% target volume (D95), and the average dose to target (Dmean) were compared. Also, the distance from the skull was analyzed. For the phantom study, a cylindrical phantom and a head phantom were used, and the delivered dose was measured by an ion chamber and EBT3 film, respectively, at various locations. The measurement was compared with the calculated doses from VMC and AXB. RESULTS In clinical cases, VMC dose calculations tended to be higher than AXB. It was found that the difference in Dref showed > 5% in some cases for smaller volumes < 0.3 cm3 . Dmean and D95 differences were also higher for small targets. No obvious trend was found between the dose difference and the distance from the skull. In phantom studies, VMC dose was also higher than AXB for smaller targets, and VMC showed better agreement with the measurements than AXB for both point dose and high dose spread. CONCLUSION The two advanced calculation algorithms were extensively compared. For brain SRS, AXB sometimes calculates a noticeable lower target dose for small targets than VMC, and VMC tends to have a slightly closer agreement with measurements than AXB.
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Affiliation(s)
- Jihyung Yoon
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Hyunuk Jung
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Sean M. Tanny
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Olga Maria Dona Lemus
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Michael T. Milano
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Sara J. Hardy
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Kenneth Y. Usuki
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Dandan Zheng
- Department of Radiation OncologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
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Yanagi Y, Kubo K, Ito T, Nakamura K, Hirata M, Doi H, Monzen H. Comparing Dose Calculation Algorithms for Heterogeneous Media: Analytical Anisotropic Algorithm Versus Acuros XB (Dm/Dw) With Continuous CT Value Variation. Cureus 2023; 15:e46805. [PMID: 37954761 PMCID: PMC10635741 DOI: 10.7759/cureus.46805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 11/14/2023] Open
Abstract
BACKGROUND To compare the doses calculated by the analytical anisotropic algorithm (AAA) and two dose reporting modes of Acuros XB (AXB(Dm) and AXB(Dw)) with varied CT values on the Eclipse (Varian Medical Systems, Palo Alto, CA). MATERIALS AND METHODS Virtual phantoms with a central layer of heterogeneous material (thickness = 2 or 5 cm) were created with Eclipse. Using single or opposed fields, the field sizes were 5 x 5 cm2 or 10 x 10 cm2. The photon energies were 6 or 10 MV, and the source-to-target distance was 100 cm. The relative doses at the center of the heterogeneous material layer were evaluated with varied CT values, from -1000 to 3000 HU. Values were normalized with the dose at 0 HU (100%) for comparative analysis. RESULTS The results obtained from continuous data for a single field, 6 MV, 5 x 5 cm2, and the heterogeneous material 5 cm, where the differences between algorithms were most pronounced, were as follows. In the low-density region (-1000 HU and -800 HU), the dose differences for AXB with reference to AAA were, respectively, -54.5% and +4.6% (AXB(Dm)) and -47.0% and +3.5% (AXB(Dw)), and in the high-density regions (1000 HU and 3000 HU) were -5.7% and -8.8% (AXB(Dm)) and +7.4% and +3.5% (AXB(Dw)), respectively. Consequently, dose differences at arbitrary CT values could be obtained. CONCLUSION Dose differences between these algorithms were clarified for heterogeneous materials. The risk of dose reduction or escalation in clinical use was clearly visible between CT values from -1000 to 3000 HU.
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Affiliation(s)
- Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
- Department of Radiology, Shiga University of Medical Science Hospital, Otsu, JPN
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Makoto Hirata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, JPN
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, JPN
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Bedford JL. A discrete ordinates Boltzmann solver for application to inverse planning of photons and protons. Phys Med Biol 2023; 68:185019. [PMID: 37643625 PMCID: PMC10498099 DOI: 10.1088/1361-6560/acf4de] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/09/2023] [Accepted: 08/29/2023] [Indexed: 08/31/2023]
Abstract
The aim of this work is to develop a discrete ordinates Boltzmann solver that can be used for calculation of absorbed dose from both photons and protons within an inverse planning optimiser, so as to perform accurate dose calculation throughout the whole of the inverse planning process. With photons, five transport sweeps were performed to obtain scattered photon fluence, and unscattered electron fluence was then obtained and used as a fixed source for solution of the electron transport equations. With protons, continuous slowing down was treated as a fixed source, and five transport sweeps were used to calculate scattered fluence. The total electron or proton fluence was multiplied by the stopping power ratio for the transport medium to obtain absorbed dose. The method was evaluated in homogeneous media and in a lung case where the planning target volume was surrounded by low-density lung material. Photon arc, proton passive scattering and proton arc treatments were considered. The results were compared to a clinically validated convolution dose calculation for photons, and with an analytical method for protons. In water-equivalent media, the discrete ordinates method agrees with the alternative algorithms to within 2%. Convergence is found to be sufficiently complete for water-, lung- and bone-equivalent materials after five iterations. The dose calculated by the relatively simple angular quadrature is seen to be very close to that calculated by a more comprehensive quadrature. For inhomogeneous lung plans, the method shows more heterogeneity of dose to the planning target volume than the comparative methods. The discrete ordinates Boltzmann solver provides a general framework for dose calculation with both photons and protons. The method is suitable for incorporation into an inverse planning optimiser, so that accurate dose calculation in a heterogeneous medium can be obtained throughout inverse planning, with the result that the final dose distribution is as predicted by the optimiser.
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Affiliation(s)
- James L Bedford
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, United Kingdom
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14
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Shaw M, Lye J, Alves A, Lehmann J, Sanagou M, Geso M, Brown R. Measuring dose in lung identifies peripheral tumour dose inaccuracy in SBRT audit. Phys Med 2023; 112:102632. [PMID: 37406592 DOI: 10.1016/j.ejmp.2023.102632] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/25/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023] Open
Abstract
PURPOSE Stereotactic Body Radiotherapy (SBRT) for lung tumours has become a mainstay of clinical practice worldwide. Measurements in anthropomorphic phantoms enable verification of patient dose in clinically realistic scenarios. Correction factors for reporting dose to the tissue equivalent materials in a lung phantom are presented in the context of a national dosimetry audit for SBRT. Analysis of dosimetry audit results is performed showing inaccuracies of common dose calculation algorithms in soft tissue lung target, inhale lung material and at tissue interfaces. METHODS Monte Carlo based simulation of correction factors for detectors in non-water tissue was performed for the soft tissue lung target and inhale lung materials of a modified CIRS SBRT thorax phantom. The corrections were determined for Gafchromic EBT3 Film and PTW 60019 microDiamond detectors used for measurements of 168 SBRT lung plans in an end-to-end dosimetry audit. Corrections were derived for dose to medium (Dm,m) and dose to water (Dw,w) scenarios. RESULTS Correction factors were up to -3.4% and 9.2% for in field and out of field lung respectively. Overall, application of the correction factors improved the measurement-to-plan dose discrepancy. For the soft tissue lung target, agreement between planned and measured dose was within average of 3% for both film and microDiamond measurements. CONCLUSIONS The correction factors developed for this work are provided for clinical users to apply to commissioning measurements using a commercially available thorax phantom where inhomogeneity is present. The end-to-end dosimetry audit demonstrates dose calculation algorithms can underestimate dose at lung tumour/lung tissue interfaces by an average of 2-5%.
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Affiliation(s)
- Maddison Shaw
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia; School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia.
| | - Jessica Lye
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia; Olivia Newton John Cancer Wellness and Research Centre, Austin Health, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
| | - Joerg Lehmann
- Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, Australia; School of Science, RMIT University, Melbourne, Australia; School of Mathematical and Physical Sciences, University of Newcastle, Australia; Institute of Medical Physics, University of Sydney, Australia
| | - Masoumeh Sanagou
- Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
| | - Moshi Geso
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia
| | - Rhonda Brown
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
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15
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Ito T, Monzen H, Kubo K, Kosaka H, Yanagi Y, Sakai Y, Inada M, Doi H, Nishimura Y. Dose difference between anisotropic analytical algorithm (AAA) and Acuros XB (AXB) caused by target's air content for volumetric modulated arc therapy of head and neck cancer. Rep Pract Oncol Radiother 2023; 28:399-406. [PMID: 37795404 PMCID: PMC10547402 DOI: 10.5603/rpor.a2023.0032] [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: 01/25/2022] [Accepted: 05/23/2022] [Indexed: 10/06/2023] Open
Abstract
Background We clarified the dose difference between the anisotropic analytical algorithm (AAA) and Acuros XB (AXB) with increasing target's air content using a virtual phantom and clinical cases. Materials and methods Whole neck volumetric modulated arc therapy (VMAT) plan was transferred into a virtual phantom with a cylindrical air structure at the center. The diameter of the air structure was changed from 0 to 6 cm, and the target's air content defined as the air/planning target volume (PTV) in percent (air/PTV) was varied. VMAT plans were recalculated by AAA and AXB with the same monitor unit (MU) and multi-leaf collimator (MLC) motions. The dose at each air/PTV (5%-30%) was compared between each algorithm with D98%, D95%, D50% and D2% for the PTV. In addition, MUs were also compared with the same MLC motions between the D95% prescription with AAA (AAA_D95%), AXB_D95%, and the prescription to 100% minus air/PTV (AXB_D100%-air/PTV) in clinical cases of head and neck (HNC). Results When air/PTV increased (5-30%), the dose differences between AAA and AXB for D98%, D95%, D50% and D2% were 3.08-15.72%, 2.35-13.92%, 0.63-4.59%, and 0.14-6.44%, respectively. At clinical cases with air/PTV of 5.61% and 28.19%, compared to AAA_D95%, the MUs differences were, respectively, 2.03% and 6.74% for AXB_D95% and 1.80% and 0.50% for AXB_D100%-air/PTV. Conclusion The dose difference between AAA and AXB increased as the target's air content increased, and AXB_D95% resulted in a dose escalation over AAA_D95% when the target's air content was ≥ 5%. The D100%-air/PTV of PTV using AXB was comparable to the D95% of PTV using AAA.
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Affiliation(s)
- Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center, Kobe, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Guo Y, Li B, Li Y, Du W, Feng W, Feng S, Miao G. Application of a linear interpolation algorithm in radiation therapy dosimetry for 3D dose point acquisition. Sci Rep 2023; 13:4539. [PMID: 36941321 PMCID: PMC10027884 DOI: 10.1038/s41598-023-31562-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 03/14/2023] [Indexed: 03/23/2023] Open
Abstract
Air-vented ion chambers are generally used in radiation therapy dosimetry to determine the absorbed radiation dose with superior precision. However, in ion chamber detector arrays, the number of array elements and their spacing do not provide sufficient spatial sampling, which can be overcome by interpolating measured data. Herein, we investigated the potential principle of the linear interpolation algorithm in volumetric dose reconstruction based on computed tomography images in the volumetric modulated arc therapy (VMAT) technique and evaluated how the ion chamber spacing and anatomical mass density affect the accuracy of interpolating new data points. Plane measurement doses on 83 VMAT treatment plans at different anatomical sites were acquired using Octavius 729, Octavius1500, and MatriXX ion chamber detector arrays, followed by the linear interpolation to reconstruct volumetric doses. Dosimetric differences in planning target volumes (PTVs) and organs at risk (OARs) between treatment planning system and reconstruction were evaluated by dose volume histogram metrics. The average percentage dose deviations in the mean dose (Dmean) of PTVs reconstructed by 729 and 1500 arrays ranged from 4.7 to 7.3% and from 1.5 to 2.3%, while the maximum dose (Dmax) counterparts ranged from 2.3 to 5.5% and from 1.6 to 7.6%, respectively. The average percentage dose/volume deviations of mixed PTVs and OARs in the abdomen/gastric and pelvic sites were 7.6%, 3.5%, and 7.2%, while mediastinum and lung plans showed slightly larger values of 8.7%, 5.1%, and 8.9% for 729, 1500, and MatriXX detector arrays, respectively. Our findings indicated that the smaller the spacing between neighbouring detectors and the more ion chambers present, the smaller the error in interpolating new data points. Anatomical regions with small local mass density inhomogeneity were associated with superior dose reconstruction. Given a large mass density difference in the various human anatomical structures and the characteristics of the linear interpolation algorithm, we suggest that an alternative data interpolation method should be used in radiotherapy dosimetry.
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Affiliation(s)
- Yixiao Guo
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Bo Li
- Department of Bone and Soft-Tissue Carcinoma, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Yazhou Li
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Wen Du
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Weigui Feng
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Shifang Feng
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China
| | - Guoying Miao
- Department of Radiation Oncology, Gansu Provincial Hospital, Lanzhou, 730000, People's Republic of China.
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Baltz GC, Manigold R, Seier R, Kirsner SM. A hybrid method to improve efficiency of patient specific SRS and SBRT QA using 3D secondary dose verification. J Appl Clin Med Phys 2023; 24:e13858. [PMID: 36583305 PMCID: PMC10018667 DOI: 10.1002/acm2.13858] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/25/2022] [Accepted: 11/20/2022] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Patient Specific QA (PSQA) by direct phantom measurement for all intensity modulated radiation therapy (IMRT) cases is labor intensive and an inefficient use of the Medical Physicist's time. The purpose of this work was to develop a hybrid quality assurance (QA) technique utilizing 3D dose verification as a screening tool to determine if a measurement is necessary. METHODS This study utilized Sun Nuclear DoseCHECK (DC), a 3D secondary verification software, and Fraction 0, a trajectory log IMRT QA software. Twenty-two Lung stereotactic body radiation therapy (SBRT) and thirty single isocentre multi-lesion SRS (MLSRS) plans were retrospectively analysed in DC. Agreement of DC and the TPS dose for selected dosimetric criteria was recorded. Calculated 95% confidence limits (CL) were used to establish action limits. All cases were delivered and measured using the Sun Nuclear stereotactic radiosurgery (SRS) MapCheck. Trajectory logs of the delivery were used to calculate Fraction 0 results for the same criteria calculated by DC. Correlation of DC and Fraction 0 results were calculated. Phantom measured QA was compared to Fraction 0 QA results for the cases which had DC criteria action limits exceeded. RESULTS Correlation of DC and Fraction 0 results were excellent, demonstrating the same action limits could be used for both and DC can predict Fraction 0 results. Based on the calculated action limits, zero lung SBRT cases and six MLSRS cases were identified as requiring a measurement. All plans that passed the DC screening had a passing measurement based PSQA and agreed with Fraction 0 results. CONCLUSION Using 95% CL action limits of dosimetric criteria, a 3D secondary dose verification can be used to determine if a measurement is required for PSQA. This method is efficient for it is part of the normal clinical workflow when verifying any clinical treatment. In addition, it can drastically reduce the number of measurements needed for PSQA.
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Affiliation(s)
- Garrett C Baltz
- Scripps MD Anderson Cancer Center, San Diego, California, USA
| | - Remy Manigold
- Scripps MD Anderson Cancer Center, San Diego, California, USA
| | - Richard Seier
- Scripps MD Anderson Cancer Center, San Diego, California, USA
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Arce P, Lagares JI, Azcona JD, Huesa-Berral C, Burguete J. Precise dosimetric comparison between GAMOS and the collapsed cone convolution algorithm of 4D DOSE accumulated in lung SBRT treatments. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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19
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Harms J, Schreibmann E, Mccall NS, Lloyd MS, Higgins KA, Castillo R. Cardiac motion and its dosimetric impact during radioablation for refractory ventricular tachycardia. J Appl Clin Med Phys 2023:e13925. [PMID: 36747376 DOI: 10.1002/acm2.13925] [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: 09/08/2022] [Revised: 12/09/2022] [Accepted: 01/19/2023] [Indexed: 02/08/2023] Open
Abstract
INTRODUCTION Cardiac radioablation (CR) is a noninvasive treatment option for patients with refractory ventricular tachycardia (VT) during which high doses of radiation, typically 25 Gy, are delivered to myocardial scar. In this study, we investigate motion from cardiac cycle and evaluate the dosimetric impact in a cohort of patients treated with CR. METHODS This retrospective study included eight patients treated at our institution who had respiratory-correlated and ECG-gated 4DCT scans acquired within 2 weeks of CR. Deformable image registration was applied between maximum systole (SYS) and diastole (DIAS) CTs to assess cardiac motion. The average respiratory-correlated CT (AVGresp ) was deformably registered to the average cardiac (AVGcardiac ), SYS, and DIAS CTs, and contours were propagated using the deformation vector fields (DVFs). Finally, the original treatment plan was recalculated on the deformed AVGresp CT for dosimetric assessment. RESULTS Motion magnitudes were measured as the mean (SD) value over the DVFs within each structure. Displacement during the cardiac cycle for all chambers was 1.4 (0.9) mm medially/laterally (ML), 1.6 (1.0) mm anteriorly/posteriorly (AP), and 3.0 (2.8) mm superiorly/inferiorly (SI). Displacement for the 12 distinct clinical target volumes (CTVs) was 1.7 (1.5) mm ML, 2.4 (1.1) mm AP, and 2.1 (1.5) SI. Displacements between the AVGresp and AVGcardiac scans were 4.2 (2.0) mm SI and 5.8 (1.4) mm total. Dose recalculations showed that cardiac motion may impact dosimetry, with dose to 95% of the CTV dropping from 27.0 (1.3) Gy on the AVGresp to 20.5 (7.1) Gy as estimated on the AVGcardiac . CONCLUSIONS Cardiac CTV motion in this patient cohort is on average below 3 mm, location-dependent, and when not accounted for in treatment planning may impact target coverage. Further study is needed to assess the impact of cardiac motion on clinical outcomes.
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Affiliation(s)
- Joseph Harms
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Eduard Schreibmann
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia, USA
| | - Neal S Mccall
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia, USA
| | - Michael S Lloyd
- Section of Clinical Cardiac Electrophysiology, Emory University, Atlanta, Georgia, USA
| | - Kristin A Higgins
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia, USA
| | - Richard Castillo
- Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia, USA
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Rostami A, Neto AJDC, Paloor SP, Khalid AS, Hammoud R. Comparison of four commercial dose calculation algorithms in different evaluation tests. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2023; 31:1013-1033. [PMID: 37393487 DOI: 10.3233/xst-230079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2023]
Abstract
BACKGROUND Accurate and fast dose calculation is crucial in modern radiation therapy. Four dose calculation algorithms (AAA, AXB, CCC, and MC) are available in Varian Eclipse and RaySearch Laboratories RayStation Treatment Planning Systems (TPSs). OBJECTIVES This study aims to evaluate and compare dosimetric accuracy of the four dose calculation algorithms applying to homogeneous and heterogeneous media, VMAT plans (based on AAPM TG-119 test cases), and the surface and buildup regions. METHODS The four algorithms are assessed in homogeneous (IAEA-TECDOCE 1540) and heterogeneous (IAEA-TECDOC 1583) media. Dosimetric evaluation accuracy for VMAT plans is then analyzed, along with the evaluation of the accuracy of algorithms applying to the surface and buildup regions. RESULTS Tests conducted in homogeneous media revealed that all algorithms exhibit dose deviations within 5% for various conditions, with pass rates exceeding 95% based on recommended tolerances. Additionally, the tests conducted in heterogeneous media demonstrate high pass rates for all algorithms, with a 100% pass rate observed for 6 MV and mostly 100% pass rate for 15 MV, except for CCC, which achieves a pass rate of 94%. The results of gamma index pass rate (GIPR) for dose calculation algorithms in IMRT fields show that GIPR (3% /3 mm) for all four algorithms in all evaluated tests based on TG119, are greater than 97%. The results of the algorithm testing for the accuracy of superficial dose reveal variations in dose differences, ranging from -11.9% to 7.03% for 15 MV and -9.5% to 3.3% for 6 MV, respectively. It is noteworthy that the AXB and MC algorithms demonstrate relatively lower discrepancies compared to the other algorithms. CONCLUSIONS This study shows that generally, two dose calculation algorithms (AXB and MC) that calculate dose in medium have better accuracy than other two dose calculation algorithms (CCC and AAA) that calculate dose to water.
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Affiliation(s)
- Aram Rostami
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | | | - Satheesh Prasad Paloor
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | - Abdul Sattar Khalid
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | - Rabih Hammoud
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
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21
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Dosimetric accuracy of Acuros ® XB and AAA algorithms for stereotactic body radiotherapy (SBRT) lung treatments: evaluation with PRIMO Monte Carlo code. JOURNAL OF RADIOTHERAPY IN PRACTICE 2023. [DOI: 10.1017/s1460396922000346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Abstract
Purpose:
The study aimed to compare the dosimetric performance of Acuros® XB (AXB) and anisotropic analytical algorithm (AAA) for lung SBRT plans using Monte Carlo (MC) simulations.
Methods:
We compared the dose calculation algorithms AAA and either of the dose reporting modes of AXB (dose to medium (AXB-Dm) or dose to water (AXB-Dw)) algorithms implemented in Eclipse® (Varian Medical Systems, Palo Alto, CA) Treatment planning system (TPS) with MC. PRIMO code was used for the MC simulations. The TPS-calculated dose profiles obtained with a multi-slab heterogeneity phantom were compared to MC. A lung phantom with a tumour was used to validate TPS algorithms using different beam delivery techniques. 2D gamma values obtained from Gafchromic film measurements in the tumour isocentre plane were compared with TPS algorithms and MC. Ten VMAT SBRT plans generated in TPS with each algorithm were recalculated with a PRIMO MC system for identical beam parameters for the clinical plan validation. A dose–volume histogram (DVH) based plan comparison and a 3D global gamma analysis were performed.
Results:
AXB demonstrated better agreement with MC and film measurements in the lung phantom validation, with good agreement in PDD, profiles and gamma analysis. AAA showed an overestimated PDD, a significant difference in dose profiles and a lower gamma pass rate near the field borders. With AAA, there was a dose overestimation at the periphery of the tumour. For clinical plan validation, AXB demonstrated higher agreement with MC than AAA.
Conclusions:
AXB provided better agreement with MC than AAA in the phantom and clinical plan evaluations.
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22
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Kosaka T, Takatsu J, Inoue T, Hara N, Mitsuhashi T, Suzuki M, Shikama N. Effective clinical applications of Monte Carlo-based independent secondary dose verification software for helical tomotherapy. Phys Med 2022; 104:112-122. [PMID: 36395639 DOI: 10.1016/j.ejmp.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 10/28/2022] [Accepted: 11/05/2022] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To investigate the scope of the effective clinical application of Monte Carlo (MC)-based independent dose verification software for helical tomotherapy. METHODS DoseCHECK was selected as the MC-based dose calculation software. First, the dose calculation accuracy of DoseCHECK was evaluated with film and chamber measurements in a water-equivalent phantom. Second, the dose calculation accuracy was examined in several heterogeneous materials. Finally, dosimetric comparisons between DoseCHECK and the treatment planning system (TPS) were performed for clinical patient plans. Prostate IMRT, head and neck IMRT (HN), total body irradiation (TBI), and brain stereotactic radiotherapy (SRT) were evaluated. RESULT The DoseCHECK calculations agreed with the chamber and film measurements in the homogenous phantom. For heterogeneous phantom cases, the dose differences between DoseCHECK and TPS were within 3 %, except in air, in which large dose differences of 20 % were observed. In clinical patient plans, the median dose differences between the lung Dmean in TBI cases and the normal brain Dmean in brain SRT cases were significantly >3 %. For HN and brain SRT cases, the median target dose differences were >3 %. CONCLUSION Our results show that independent dose verification with the MC algorithm can detect systematic errors caused by the lack of heterogeneity correction in the TPS. In particular, MC-based independent dose verification is required for HN, TBI, and brain SRT cases in helical tomotherapy.
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Affiliation(s)
- Takahiro Kosaka
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan.
| | - Jun Takatsu
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Tatsuya Inoue
- Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan; Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Naoya Hara
- Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431, Japan.
| | - Taira Mitsuhashi
- Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan.
| | - Michimasa Suzuki
- Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan.
| | - Naoto Shikama
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431, Japan.
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23
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Geurts MW, Jacqmin DJ, Jones LE, Kry SF, Mihailidis DN, Ohrt JD, Ritter T, Smilowitz JB, Wingreen NE. AAPM MEDICAL PHYSICS PRACTICE GUIDELINE 5.b: Commissioning and QA of treatment planning dose calculations-Megavoltage photon and electron beams. J Appl Clin Med Phys 2022; 23:e13641. [PMID: 35950259 PMCID: PMC9512346 DOI: 10.1002/acm2.13641] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 11/23/2022] Open
Abstract
The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines will be reviewed for the purpose of revision or renewal, as appropriate, on their fifth anniversary or sooner. Each medical physics practice guideline represents a policy statement by the AAPM, has undergone a thorough consensus process in which it has been subjected to extensive review, and requires the approval of the Professional Council. The medical physics practice guidelines recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guidelines and technical standards by those entities not providing these services is not authorized. The following terms are used in the AAPM practice guidelines:
Must and Must Not: Used to indicate that adherence to the recommendation is considered necessary to conform to this practice guideline. While must is the term to be used in the guidelines, if an entity that adopts the guideline has shall as the preferred term, the AAPM considers that must and shall have the same meaning. Should and Should Not: Used to indicate a prudent practice to which exceptions may occasionally be made in appropriate circumstances.
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Wang L, Zhang J, Huang M, Xu B, Li X. Radiobiological Comparison of Acuros External Beam and Anisotropic Analytical Algorithm on Esophageal Carcinoma Radiotherapy Treatment Plans. Dose Response 2022; 20:15593258221105678. [PMID: 35832770 PMCID: PMC9272482 DOI: 10.1177/15593258221105678] [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] [Indexed: 11/17/2022] Open
Abstract
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, αβ=10 ) of AXB-Dm due to dose non-uniformity exceeded 6.5%, even
for a small σ. 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 ΔγAAAAXB−Dw, ΔγAAAAXB−Dm, and ΔγAXB−DmAXB−Dw 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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Affiliation(s)
- Lin Wang
- Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, China.,Department of Medical Imaging Technology, College of Medical Technology and Engineering, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Intelligent Imaging and Precision Radiotherapy for Tumors, Fujian Medical University, Fuzhou, China.,Clinical Research Center for Radiology and Radiotherapy of Fujian Province Digestive, Hematological and Breast Malignancies, Fuzhou, China
| | - Jianping Zhang
- Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, China.,Department of Medical Imaging Technology, College of Medical Technology and Engineering, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Intelligent Imaging and Precision Radiotherapy for Tumors, Fujian Medical University, Fuzhou, China.,Clinical Research Center for Radiology and Radiotherapy of Fujian Province Digestive, Hematological and Breast Malignancies, Fuzhou, China.,Fujian Medical University Union Clinical Medicine College, Fujian Medical University, Fuzhou, China
| | - Miaoyun Huang
- Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, China.,Fujian Key Laboratory of Intelligent Imaging and Precision Radiotherapy for Tumors, Fujian Medical University, Fuzhou, China.,Clinical Research Center for Radiology and Radiotherapy of Fujian Province Digestive, Hematological and Breast Malignancies, Fuzhou, China
| | - Benhua Xu
- Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, China.,Department of Medical Imaging Technology, College of Medical Technology and Engineering, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Intelligent Imaging and Precision Radiotherapy for Tumors, Fujian Medical University, Fuzhou, China.,Clinical Research Center for Radiology and Radiotherapy of Fujian Province Digestive, Hematological and Breast Malignancies, Fuzhou, China.,Fujian Medical University Union Clinical Medicine College, Fujian Medical University, Fuzhou, China
| | - Xiaobo Li
- Department of Radiation Oncology, Fujian Medical University Union Hospital, Fuzhou, China.,Department of Medical Imaging Technology, College of Medical Technology and Engineering, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Intelligent Imaging and Precision Radiotherapy for Tumors, Fujian Medical University, Fuzhou, China.,Clinical Research Center for Radiology and Radiotherapy of Fujian Province Digestive, Hematological and Breast Malignancies, Fuzhou, China.,Fujian Medical University Union Clinical Medicine College, Fujian Medical University, Fuzhou, China
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25
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Cheung MLM, Chow VUY, Kan MWK, Chan ATC. The effect of material assignment in nasal cavity on dose calculation for nasopharyngeal carcinoma (NPC) using Acuros XB. J Appl Clin Med Phys 2022; 23:e13698. [PMID: 35699203 PMCID: PMC9359034 DOI: 10.1002/acm2.13698] [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: 02/16/2022] [Revised: 04/21/2022] [Accepted: 05/28/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate the effect of material assignment in nasal cavity on dose calculation for the volumetric modulated arc therapy (VMAT) of nasopharyngeal carcinoma (NPC) using Acuros XB (AXB) algorithm. METHODS The VMAT plans of 30 patients with NPC were calculated using AXB with material auto-assignment of nasal cavity to lung and reassignment to air respectively. The doses to the planning target volumes (PTVs) overlapping with nasal cavity with material auto-assignment of lung (AXB_Lung) were compared to the values obtained when nasal cavity was reassigned to air (AXB_Air) under the dose-to-medium (Dm ) reporting mode of AXB. RESULTS For dose calculated under AXB_Lung, the D98% , D2% , and Dmean of the PTV69.96 _Air Cavity (PTV of prescription dose 69.96 Gy overlapping with nasal cavity) were on average 16.1%, 1.6%, and 8.6% larger than that calculated under AXB_Air, respectively. Up to 19.5% difference in D98% , 3% difference in D2% , and 11.2% difference in Dmean were observed in the worst cases for PTV69.96 . Similar trend was observed for the PTV5940 _Air Cavity, in which the D98% , D2% , and Dmean calculated under AXB_Lung were on average 14.7%, 2.5%, and 10.2% larger than that calculated under AXB_Air, respectively. In the worst cases, the difference observed in D98% , D2% , and Dmean could be up to 17.7%, 4.5%, and 12.7%, respectively. CONCLUSIONS Significant dose difference calculated by AXB between the material assignment of lung and air in nasal cavity for NPC cases might imply the possibility of underdosage to the PTVs that overlap with inhomogeneity. Therefore, attention should be put to ensure that accurate material assignment for dose calculation under AXB such that optimal dosage was given for tumor control.
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Affiliation(s)
- Michael L M Cheung
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China
| | - Vivian U Y Chow
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China
| | - Monica W K Kan
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China.,Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Anthony T C Chan
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China.,Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
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26
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Pawałowski B, Ryczkowski A, Panek R, Sobocka-Kurdyk U, Graczyk K, Piotrowski T. Accuracy of the doses computed by the Eclipse treatment planning system near and inside metal elements. Sci Rep 2022; 12:5974. [PMID: 35396569 PMCID: PMC8993896 DOI: 10.1038/s41598-022-10072-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/25/2022] [Indexed: 11/09/2022] Open
Abstract
Metal artefacts degrade clinical image quality which decreases the confidence of using computed tomography (CT) for the delineation of key structures for treatment planning and leads to dose errors in affected areas. In this work, we investigated accuracy of doses computed by the Eclipse treatment planning system near and inside metallic elements for two different computation algorithms. An impact of CT metal artefact reduction methods on the resulting calculated doses has also been assessed. A water phantom including Gafchromic film and metal inserts was irradiated (max dose 5 Gy) using a 6 MV photon beam. Three materials were tested: titanium, alloy 600, and tungsten. The phantom CT images were obtained with the pseudo-monoenergetic reconstruction (PMR) and the iterative metal artefact reduction (iMAR). Image sets were used for dose calculation using an Eclipse treatment planning station (TPS). Monte Carlo (MC) simulations were used to predict the true dose distribution in the phantom allowing for comparison with doses measured by film and calculated by TPS. Measured and simulated percentage depth doses (PDDs) were not statistically different (p > 0.618). Regional differences were observed at edges of metallic objects (max 8% difference). However, PDDs simulated with and without film were statistically different (p < 0.002). PDDs calculated by the Acuros XB algorithm based on the dose-to-medium approach best matched the MC reference regardless of the CT reconstruction methods and inserts used (p > 0.078). PDDs obtained using other algorithms significantly differ from the MC values (p < 0.011). The Acuros XB algorithm with a dose-to-medium approach provides reliable dose calculation in all metal regions when using the Varian system. The inability of the AAA algorithm to model backscatter dose significantly limits its clinical application in the presence of metal. No significant impact on the dose calculation was found for a range of metal artefact reduction strategies.
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Affiliation(s)
- Bartosz Pawałowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Department of Technical Physics, Poznan University of Technology, Poznan, Poland
| | - Adam Ryczkowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Rafał Panek
- Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham, UK.,School of Medicine, University of Nottingham, Nottingham, UK
| | - Urszula Sobocka-Kurdyk
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Faculty of Health Sciences, Calisia University, Kalisz, Poland
| | - Kinga Graczyk
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland
| | - Tomasz Piotrowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland. .,Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland.
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Sarigul N. Evaluation of the effect of field sizes on radiation dose in the presence of metal materials using Monte Carlo simulation. Appl Radiat Isot 2022; 182:110143. [DOI: 10.1016/j.apradiso.2022.110143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 01/21/2022] [Accepted: 02/07/2022] [Indexed: 11/02/2022]
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28
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Cheung MLM, Kan MWK, Yeung VTY, Poon DMC, Kam MKM, Lee LKY, Chan ATC. The radiobiological effect of using Acuros XB vs anisotropic analytical algorithm on hepatocellular carcinoma stereotactic body radiation therapy. Med Dosim 2022; 47:161-165. [PMID: 35241348 DOI: 10.1016/j.meddos.2022.01.004] [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: 10/22/2021] [Revised: 01/23/2022] [Accepted: 01/31/2022] [Indexed: 11/26/2022]
Abstract
The purpose of this work was to study the radiobiological effect of using Acuros XB (AXB) vs Analytic Anisotropic Algorithm (AAA) on hepatocellular carcinoma (HCC) stereotactic body radiation therapy (SBRT). Seventy SBRT volumetric modulated arc therapy (VMAT) plans for HCC were calculated using AAA and AXB respectively with the same treatment parameters. Published tumor control probability (TCP) and normal tissue complication probability (NTCP) models were used to quantify the effect of dosimetric difference between AAA and AXB on TCP, NTCP and uncomplicated tumor control probability (UTCP). There was an average decrease of 2.5% in 6-month TCP. Normal liver has the largest average decrease in NTCP which was 59.7%. Bowels followed with 26.6% average decrease in NTCP. Duodenum, stomach and esophagus had 10.2%, 5.1%, and 4.3% average decrease in NTCP. There was an average decrease of 1.8% and up to 7.2% in 6-month UTCP. There was an overall decrease in TCP, NTCP, and UTCP for HCC SBRT plans calculated using AXB compared to AAA which could be clinically significant.
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Affiliation(s)
- Michael L M Cheung
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China; State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Monica W K Kan
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China; State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Vanessa T Y Yeung
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China; State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Darren M C Poon
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Michael K M Kam
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Louis K Y Lee
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Anthony T C Chan
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong SAR, China; State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
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Cheung MLM, Kan MW, Yeung VT, Poon DM, Kam MK, Lee LK, Chan AT. The effect on tumour control probability of using AXB algorithm in replacement of AAA for SBRT of hepatocellular carcinoma located at lung-liver boundary region. BJR Open 2021; 3:20210041. [PMID: 34877460 PMCID: PMC8611685 DOI: 10.1259/bjro.20210041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/16/2021] [Accepted: 09/30/2021] [Indexed: 11/19/2022] Open
Abstract
Objective: To retrospectively analyze the clinical impact on stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) located at lung–liver boundary due to the use of Acuros XB algorithm (AXB) in replacement of anisotropic analytical algorithm (AAA). Methods: 23 SBRT volumetric modulated arc therapy (VMAT) plans for HCC located at lung–liver boundary were calculated using AAA and AXB respectively with the same treatment parameters. The dose–volume data of the planned target volumes (PTVs) were compared. A published tumour control probability (TCP) model was used to calculate the effect of dosimetric difference between AAA and AXB on tumour control probability. Results: For dose calculated by AXB (Dose to medium), the D95% and D98% of the PTV were on average 2.4 and 3.1% less than that calculated by AAA. For dose calculated by AXB (dose to water), the D95% and D98% of the PTV were on average 1.8%, and 2.7% less than that calculated by AAA. Up to 5% difference in D95% and 8% difference in D98% were observed in the worst cases. The significant decrease in D95% calculated by AXB compared to AAA could result in a % decrease in 2 year TCP up to 8% in the worst case (from 46.8 to 42.9%). Conclusion: The difference in dose calculated by AAA and AXB could lead to significant difference in TCP for HCC SBRT located at lung–liver boundary region. Advances in knowledge: The difference in calculated dose and tumour control probability for HCC SBRT between AAA and AXB algorithm at lung–liver boundary region was compared.
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Affiliation(s)
| | | | | | - Darren Mc Poon
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Michael Km Kam
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Louis Ky Lee
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong, SAR, China
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Webster M, Tanny S, Joyce N, Herman A, Chen Y, Milano M, Usuki K, Constine L, Singh D, Yeo I. New dosimetric guidelines for linear Boltzmann transport equations through comparative evaluation of stereotactic body radiation therapy for lung treatment planning. J Appl Clin Med Phys 2021; 22:115-124. [PMID: 34783438 PMCID: PMC8664148 DOI: 10.1002/acm2.13464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 11/12/2022] Open
Abstract
Purpose To propose guidelines for lung stereotactic body radiation therapy (SBRT) when using Acuros XB (AXB) equivalent to the existing ones developed for convolution algorithms such as analytic anisotropic algorithm (AAA), considering the difference between the algorithms. Methods A retrospective analysis was performed on 30 lung patients previously treated with SBRT. The original AAA plans, which were developed using dynamic conformal arcs, were recalculated and then renormalized for planning target volume (PTV) coverage using AXB. The recalculated and renormalized plans were compared to the original plans based on V100% and V90% PTV coverage, as well as V105%, conformality index, D2cm, Rx/Dmax, R50, and Dmin. These metrics were analyzed nominally and on variations according to RTOG and NRG guidelines. Based on the relative difference between each metric in the AAA and AXB plans, new guidelines were developed. The relative differences in our cohort were compared to previously documented AAA to AXB comparisons found in the literature. Results AAA plans recalculated in AXB had a significant reduction in most dosimetric metrics. The most notable changes were in V100% (4%) and the conformality index (7.5%). To achieve equal PTV coverage, AXB required an average of 1.8% more monitor units (MU). This fits well with previously published data. Applying the new guidelines to the AXB plans significantly increased the number of minor violations with no change in major violations, making them comparable to those of the original AAA plans. Conclusion The relative difference found between AAA and AXB for SBRT lung plans has been shown to be consistent with previous works. Based on these findings, new guidelines for lung SBRT are recommended when planning with AXB.
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Affiliation(s)
- Matthew Webster
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Sean Tanny
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Neil Joyce
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Amy Herman
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Yuhchyau Chen
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Michael Milano
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Kenneth Usuki
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Louis Constine
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Deepinder Singh
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
| | - Inhwan Yeo
- Department of Radiation Oncology, University of Rochester, Rochester, New York, USA
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Shen Z, Tan X, Li S, Tian X, Luo H, Wang Y, Jin F. Correlation between the γ passing rates of IMRT plans and the volumes of air cavities and bony structures in head and neck cancer. Radiat Oncol 2021; 16:134. [PMID: 34289863 PMCID: PMC8296469 DOI: 10.1186/s13014-021-01861-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/15/2021] [Indexed: 12/31/2022] Open
Abstract
Background Both patient-specific dose recalculation and γ passing rate analysis are important for the quality assurance (QA) of intensity modulated radiotherapy (IMRT) plans. The aim of this study was to analyse the correlation between the γ passing rates and the volumes of air cavities (Vair) and bony structures (Vbone) in target volume of head and neck cancer. Methods Twenty nasopharyngeal carcinoma and twenty nasal natural killer T-cell lymphoma patients were enrolled in this study. Nine-field sliding window IMRT plans were produced and the dose distributions were calculated by anisotropic analytical algorithm (AAA), Acuros XB algorithm (AXB) and SciMoCa based on the Monte Carlo (MC) technique. The dose distributions and γ passing rates of the targets, organs at risk, air cavities and bony structures were compared among the different algorithms. Results The γ values obtained with AAA and AXB were 95.6 ± 1.9% and 96.2 ± 1.7%, respectively, with 3%/2 mm criteria (p > 0.05). There were significant differences (p < 0.05) in the γ values between AAA and AXB in the air cavities (86.6 ± 9.4% vs. 98.0 ± 1.7%) and bony structures (82.7 ± 13.5% vs. 99.0 ± 1.7%). Using AAA, the γ values were proportional to the natural logarithm of Vair (R2 = 0.674) and inversely proportional to the natural logarithm of Vbone (R2 = 0.816). When the Vair in the targets was smaller than approximately 80 cc or the Vbone in the targets was larger than approximately 6 cc, the γ values of AAA were below 95%. Using AXB, no significant relationship was found between the γ values and Vair or Vbone. Conclusion In clinical head and neck IMRT QA, greater attention should be paid to the effect of Vair and Vbone in the targets on the γ passing rates when using different dose calculation algorithms.
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Affiliation(s)
- Zhengwen Shen
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Xia Tan
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Shi Li
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Xiumei Tian
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Huanli Luo
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Ying Wang
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Fu Jin
- Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, 400030, China.
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Zhu TC, Stathakis S, Clark JR, Feng W, Georg D, Holmes SM, Kry SF, Ma CMC, Miften M, Mihailidis D, Moran JM, Papanikolaou N, Poppe B, Xiao Y. Report of AAPM Task Group 219 on independent calculation-based dose/MU verification for IMRT. Med Phys 2021; 48:e808-e829. [PMID: 34213772 DOI: 10.1002/mp.15069] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/25/2021] [Accepted: 06/21/2021] [Indexed: 11/06/2022] Open
Abstract
Independent verification of the dose per monitor unit (MU) to deliver the prescribed dose to a patient has been a mainstay of radiation oncology quality assurance (QA). We discuss the role of secondary dose/MU calculation programs as part of a comprehensive QA program. This report provides guidelines on calculation-based dose/MU verification for intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) provided by various modalities. We provide a review of various algorithms for "independent/second check" of monitor unit calculations for IMRT/VMAT. The report makes recommendations on the clinical implementation of secondary dose/MU calculation programs; on commissioning and acceptance of various commercially available secondary dose/MU calculation programs; on benchmark QA and periodic QA; and on clinically reasonable action levels for agreement of secondary dose/MU calculation programs.
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Affiliation(s)
- Timothy C Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Wenzheng Feng
- Department of Radiation Oncology, Columbia University, New York, NY, USA
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University Vienna, Vienna, Austria
| | | | - Stephen F Kry
- IROC, UT MD Anderson Cancer Center, Houston, TX, USA
| | | | - Moyed Miften
- Department of Radiation Oncology, University of Colorado Denver, Aurora, CO, USA
| | - Dimitris Mihailidis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jean M Moran
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Bjorn Poppe
- Pius Hospital & Carl von Ossietzky University, Oldenburg, Germany
| | - Ying Xiao
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
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Ruiz Boiset G, V S Batista D, Coutinho Cardoso S. Clinical verification of treatment planning dose calculation in lung SBRT with GATE Monte Carlo simulation code. Phys Med 2021; 87:1-10. [PMID: 34091196 DOI: 10.1016/j.ejmp.2021.05.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/04/2021] [Accepted: 05/21/2021] [Indexed: 12/31/2022] Open
Abstract
PURPOSE This study aims to use GATE/Geant4 simulation code to evaluate the performance of dose calculations with Anisotropic Analytical Algorithm (AAA) in the context of lung SBRT for complex treatments considering images of patients. METHODS Four cases of non-small cell lung cancer treated with SBRT were selected for this study. Irradiation plans were created with AAA and recalculated end to end using Monte Carlo (MC) method maintaining field configurations identical to the original plans. Each treatment plan was evaluated in terms of PTV and organs at risk (OARs) using dose-volume histograms (DVH). Dosimetric parameters obtained from DVHs were used to compare AAA and MC. RESULTS The comparison between the AAA and MC DVH using gamma analysis with the passing criteria of 3%/3% showed an average passing rate of more than 90% for the PTV structure and 97% for the OARs. Tightening the criteria to 2%/2% showed a reduction in the average passing rate of the PTV to 86%. The agreement between the AAA and MC dose calculations for PTV dosimetric parameters (V100; V90; Homogeneity index; maximum, minimum and mean dose; CIPaddick and D2cm) was within 18.4%. For OARs, the biggest differences were observed in the spinal cord and the great vessels. CONCLUSIONS In general, we did not find significant differences between AAA and MC. The results indicate that AAA could be used in complex SBRT cases that involve a larger number of small treatment fields in the presence of tissue heterogeneities.
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Affiliation(s)
- Gisell Ruiz Boiset
- Instituto de Fı́sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Delano V S Batista
- Instituto de Radioproteção e Dosimetria, IRD/CNEN, Rio de Janeiro, Brazil; Oncologia D'Or São Cristóvão, Rede D'Or São Luiz, Rio de Janeiro, Brazil
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Teimoori Khandan L, Kashian S, Rezaeian P, Yousefi Diba A. Calculating the Medium Correction Factor for the PTW-30013 Ionization Chamber. IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY, TRANSACTIONS A: SCIENCE 2021. [DOI: 10.1007/s40995-021-01092-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cheng ZJ, Bromley RM, Oborn B, Booth JT. Radiotherapy dose calculations in high-Z materials: comprehensive comparison between experiment, Monte Carlo, and conventional planning algorithms. Biomed Phys Eng Express 2021; 7. [PMID: 33836524 DOI: 10.1088/2057-1976/abf6ac] [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: 02/18/2021] [Accepted: 04/09/2021] [Indexed: 11/12/2022]
Abstract
Purpose. To compare the accuracies of the AAA and AcurosXB dose calculation algorithms and to predict the change in the down-stream and lateral dose deposition of high energy photons in the presence of material with densities higher that commonly found in the body.Method. Metal rods of titanium (d = 4.5 g cm-3), stainless steel (d = 8 g cm-3) and tungsten (d = 19.25 g cm-3) were positioned in a phantom. Film was position behind and laterally to the rods to measure the dose distribution for a 6 MV, 18 MV and 10 FFF photon beams. A DOSXYZnrc Monte Carlo simulation of the experimental setup was performed. The AAA and AcurosXB dose calculation algorithms were used to predict the dose distributions. The dose from film and DOSXYZnrc were compared with the dose predicted by AAA and AcurosXB.Results. AAA overestimated the dose behind the rods by 15%-25% and underestimated the dose laterally to the rods by 5%-15% depending on the range of materials and energies investigated. AcurosXB overestimated the dose behind the rods by 1%-18% and underestimated the dose laterally to the rods by up to 5% depending on the range of material and energies investigated.Conclusion. AAA cannot deliver clinically acceptable dose calculation results at a distance less than 10 mm from metals, for a single field treatment. Acuros XB is able to handle metals of low atomic numbers (Z ≤ 26), but not tungsten (Z = 74). This can be due to the restriction of the CT-density table in EclipseTMTPS, which has an upper HU limit of 10501.
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Affiliation(s)
- Zhangkai J Cheng
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, People's Republic of China.,School of Physics, University of Sydney, Sydney NSW, Australia
| | - Regina M Bromley
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia
| | - Brad Oborn
- Illawarra Cancer Care Centre, Wollongong Hospital, Australia.,Centre for Medical Radiation Physics (CMRP), University of Wollongong, Australia
| | - Jeremy T Booth
- School of Physics, University of Sydney, Sydney NSW, Australia.,Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia
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Zaghian R, Sedighi Pashaki A, Haghparast A, Gholami MH, Mohammadi M. Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments. J Biomed Phys Eng 2021; 11:143-150. [PMID: 33937122 PMCID: PMC8064127 DOI: 10.31661/jbpe.v0i0.1121] [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: 01/22/2019] [Accepted: 02/16/2019] [Indexed: 11/16/2022]
Abstract
Background: The use of small fields has increased by the emergence of advanced radiotherapy. Dose calculations of these fields are complex and challenging for many reasons such as lack of electrical equilibrium even in homogeneous environments, and this complexity will increase in presence of heterogeneity. According to the importance of delivery the accurate prescription dose to the target volume in the patient’s body, the dose calculation accuracy of used commercial algorithms in clinical treatment planning systems (TPS) should be evaluated. Objective: The present study aims to evaluate the accuracy of Collapsed-cone dose measurement algorithm in Isogray treatment planning system. Material and Methods: In this analytical study, the measurements were made in tissue equivalent solid water phantom with lung and bone heterogeneities by Pinpoint dosimeter (0.015 cm3 sensitive volume) in several radiation fields (1×1 to 5×5 cm2). The phantoms were irradiated with 6, 10 and 18 MV photon beams and finally, the results of experimental calculations were compared with treatment planning outputs. Results: In all setups, the maximum deviation occurred in the field of 1×1 cm2. Then, the maximum deviation was observed for 2×2 cm2 field size; however, it was up to 5% for homogeneous water phantom and lung heterogeneity. In 3×3 cm2 and larger fields, there was a good agreement between the results of the TPS and experimental dosimetry. The maximum deviation was observed in water-bone heterogeneity. Conclusion: This algorithm was able to pass the standard audit criteria, but it is better to be used more cautiously in bone heterogeneity, especially in low energies.
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Affiliation(s)
- Razieh Zaghian
- MSc, Medical Physics Department, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Abdolazim Sedighi Pashaki
- MD, Radiation oncologist, Faculty of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran
| | - Abbas Haghparast
- PhD, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohammad Hadi Gholami
- PhD, Medical Physicist of Radiotherapy, Mahdieh Radiotherapy and Brachytherapy Charity Center, Hamedan, Iran
| | - Mahdi Mohammadi
- MSc, Medical Physics Department, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
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Shaw M, Lye J, Alves A, Hanlon M, Lehmann J, Supple J, Porumb C, Williams I, Geso M, Brown R. Measuring the dose in bone for spine stereotactic body radiotherapy. Phys Med 2021; 84:265-273. [PMID: 33773909 DOI: 10.1016/j.ejmp.2021.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/08/2021] [Accepted: 03/05/2021] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Current quality assurance of radiotherapy involving bony regions generally utilises homogeneous phantoms and dose calculations, ignoring the challenges of heterogeneities with dosimetry problems likely occurring around bone. Anthropomorphic phantoms with synthetic bony materials enable realistic end-to-end testing in clinical scenarios. This work reports on measurements and calculated corrections required to directly report dose in bony materials in the context of comprehensive end-to-end dosimetry audit measurements (63 plans, 6 planning systems). MATERIALS AND METHODS Radiochromic film and microDiamond measurements were performed in an anthropomorphic spine phantom containing bone equivalent materials. Medium dependent correction factors, kmed, were established using 6 MV and 10 MV Linear Accelerator Monte Carlo simulations to account for the detectors being calibrated in water, but measuring in regions of bony material. Both cortical and trabecular bony material were investigated for verification of dose calculations in dose-to-medium (Dm,m) and dose-to-water (Dw,w) scenarios. RESULTS For Dm,m calculations, modelled correction factors for cortical and trabecular bone in film measurements, and for trabecular bone in microDiamond measurements were 0.875(±0.1%), 0.953(±0.3%) and 0.962(±0.4%), respectively. For Dw,w calculations, the corrections were 0.920(±0.1%), 0.982(±0.3%) and 0.993(±0.4%), respectively. In the audit, application of the correction factors improves the mean agreement between treatment plans and measured microDiamond dose from -2.4%(±3.9%) to 0.4%(±3.7%). CONCLUSION Monte Carlo simulations provide a method for correcting the dose measured in bony materials allowing more accurate comparison with treatment planning system doses. In verification measurements, algorithm specific correction factors should be applied to account for variations in bony material for calculations based on Dm,m and Dw,w.
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Affiliation(s)
- Maddison Shaw
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia; School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia.
| | - Jessica Lye
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia; Olivia Newton John Cancer Wellness Centre, Melbourne, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
| | - Maximilian Hanlon
- Primary Standards Dosimetry Laboratory, ARPANSA, Melbourne, Australia
| | - Joerg Lehmann
- Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, Australia; School of Science, RMIT University, Melbourne, Australia; School of Mathematical and Physical Sciences, University of Newcastle, Australia; Institute of Medical Physics, University of Sydney, Australia
| | - Jeremy Supple
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
| | - Claudiu Porumb
- Alfred Health Radiation Oncology, The Alfred Hospital, Melbourne, Australia
| | - Ivan Williams
- Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
| | - Moshi Geso
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia
| | - Rhonda Brown
- Australian Clinical Dosimetry Service, Australian Radiation Protection and Nuclear Safety Agency, Melbourne, Australia
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Martin-Martin G, Walter S, Guibelalde E. Dose accuracy improvement on head and neck VMAT treatments by using the Acuros algorithm and accurate FFF beam calibration. ACTA ACUST UNITED AC 2021; 26:73-85. [PMID: 33948305 DOI: 10.5603/rpor.a2021.0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/22/2020] [Indexed: 11/25/2022]
Abstract
Background The purpose of this study was to assess dose accuracy improvement and dosimetric impact of switching from the anisotropic analytical algorithm (AA) to the Acuros XB algorithm (AXB) when performing an accurate beam calibration in head and neck (H&N) FFF-VMAT treatments. Materials and methods Twenty H&N cancer patients treated with FFF-VMAT techniques were included. Calculations were performed with the AA and AXB algorithm (dose-to-water - AXBw- and dose-to-medium - AXBm-). An accurate beam calibration was used for AXB calculations. Dose prescription to the tumour (PTV70) and at-risk-nodal region (PTV58.1) were 70 Gy and 58.1 Gy, respectively. A PTV70_bone including bony structures in PTV70 was contoured. Dose-volume parameters were compared between the algorithms. Statistical tests were used to analyze the differences in mean values and the correlation between compliance with the D95 > 95% requirement and occurrence of local recurrence. Results AA systematically overestimated the dose compared to AXB algorithm with mean dose differences within 1.3 Gy/2%, except for the PTV70_bone (2.2 Gy/3.2%). Dose differences were significantly higher for AXBm calculations when including accurate beam calibration (maximum dose differences up to 2.8 Gy/4.1% and 4.2 Gy/6.3% for PTV70 and PTV70_bone, respectively). 80% of AA-calculated plans did not meet the D95 > 95% requirement after recalculation with AXBm and accurate beam calibration. The reduction in D95 coverage in the tumour was not clinically relevant. Conclusions Using the AXBm algorithm and carefully reviewing the beam calibration procedure in H&N FFF-VMAT treatments ensures (1) dose accuracy increase by approximately 3%; (2) a consequent dose increase in targets; and (3) a dose reporting mode that is consistent with the trend of current algorithms.
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Affiliation(s)
- Guadalupe Martin-Martin
- Medical Physics and Radiation Protection Service, Hospital Universitario de Fuenlabrada, Madrid, Spain
| | - Stefan Walter
- Department of Medicine and Public Health, Rey Juan Carlos University, Alcorcón, Spain
| | - Eduardo Guibelalde
- Medical Physics Group, Department of Radiology, University Complutense of Madrid, Madrid, Spain
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Clemente S, Falco MD, Cagni E, Talamonti C, Boccia M, Gino E, Lorenzini E, Rosica F, Russo S, Alparone A, Zefiro D, Fiandra C. The influence of small field output factors simulated uncertainties on the calculated dose in VMAT plans for brain metastases: a multicentre study. Br J Radiol 2021; 94:20201354. [PMID: 33481637 DOI: 10.1259/bjr.20201354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES This multicentric study was carried out to investigate the impact of small field output factors (OFs) inaccuracies on the calculated dose in volumetric arctherapy (VMAT) radiosurgery brain plans. METHODS Nine centres, realised the same five VMAT plans with common planning rules and their specific clinical equipment Linac/treatment planning system commissioned with their OFs measured values (OFbaseline). In order to simulate OFs errors, two new OFs sets were generated for each centre by changing only the OFs values of the smallest field sizes (from 3.2 × 3.2 cm2 to 1 × 1 cm2) with well-defined amounts (positive and negative). Consequently, two virtual machines for each centre were recommissioned using the new OFs and the percentage dose differences ΔD (%) between the baseline plans and the same plans recalculated using the incremented (OFup) and decremented (OFdown) values were evaluated. The ΔD (%) were analysed in terms of planning target volume (PTV) coverage and organs at risk (OARs) sparing at selected dose/volume points. RESULTS The plans recalculated with OFdown sets resulted in higher variation of doses than baseline within 1.6 and 3.4% to PTVs and OARs respectively; while the plans with OFup sets resulted in lower variation within 1.3% to both PTVs and OARs. Our analysis highlights that OFs variations affect calculated dose depending on the algorithm and on the delivery mode (field jaw/MLC-defined). The Monte Carlo (MC) algorithm resulted significantly more sensitive to OFs variations than all of the other algorithms. CONCLUSION The aim of our study was to evaluate how small fields OFs inaccuracies can affect the dose calculation in VMAT brain radiosurgery treatments plans. It was observed that simulated OFs errors, return dosimetric calculation accuracies within the 3% between concurrent plans analysed in terms of percentage dose differences at selected dose/volume points of the PTV coverage and OARs sparing. ADVANCES IN KNOWLEDGE First multicentre study involving different Planning/Linacs about undetectable errors in commissioning output factor for small fields.
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Affiliation(s)
- Stefania Clemente
- Unit of Medical Physics and Radioprotection, Federico II University Hospital, Napoli, Italy
| | - Maria Daniela Falco
- Department of Radiation Oncology, "G. D'Annunzio" University, "SS. Annunziata" Hospital, Chieti, Italy
| | - Elisabetta Cagni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Cinzia Talamonti
- Medical Physics Unit, University Of Florence, Azienda Ospedaliero Universitaria Careggi, Florence, Italy
| | | | - Eva Gino
- Medical PhysicDepartment, A.O. Ordine Mauriziano, Turin, Italy
| | - Elena Lorenzini
- U.O.C Fisica Sanitaria Area Nord, Azienda USL Nord Ovest Toscana, Massa Carrara, Italy
| | | | | | | | - Daniele Zefiro
- MedicaPhysics Unit, ASL5 Sistema Sanitario Regione Liguria, La Spezia, Italy
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Toyota M, Oku Y, Saigo Y. [Basic Research on Comparative Evaluation of Calculated Dose Distribution Using Monte Carlo Algorithm-equipped Treatment Planning Systems in Volumetric Modulated Arc Therapy]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:795-804. [PMID: 34421067 DOI: 10.6009/jjrt.2021_jsrt_77.8.795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
PURPOSE The purpose was to study comparative evaluation of calculated dose distribution by X-ray Voxel Monte Carlo (XVMC) for dose calculation in Acuros XB (AXB). The dose commissioning and head and neck volumetric modulated arc therapy (VMAT) clinical cases were compared for AXB in Eclipse and XVMC in Monaco. METHODS For TrueBeam at 6 MV, we compared the dose commissioning for simple rectangle, heterogeneity correction, and multileaf collimator (MLC) characteristics. 15 clinical cases were compared for computation times, calculation accuracy, dose-volume histogram (DVH), and 3D-γ analysis (γ 3%/2 mm). RESULTS There was no difference between the calculated values of jaw field, the measurement errors of both were within± 1%, and the dose profiles of water, bone, and lung equivalent slab phantoms were in good agreement. There was no difference in transmission, tongue and groove effect, and there was a difference of less than 10% in leaf-end transmission. In clinical cases, the computation time of XVMC was a half time that of AXB, the average values of the dose difference between the two dose calculations were -1.17±2.14%, and there was no difference in measurement error (AXB: -0.73±0.79%, XVMC: -0.07±1.21%). In DVH, max doses of XVMC were about 3% higher in planning target volume (PTV) and gross tumor volume (GTV), but the pass rate of 3D-γ analysis was overall 95.11±2.59%, which was in good agreement. CONCLUSIONS Both dose calculation algorithms were equivalent, suggesting that Monaco XVMC is a verification method with a high accuracy for comparative evaluation of calculated dose distribution.
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Affiliation(s)
- Masahiko Toyota
- Division of Radiology, Department of Clinical Technology, Kagoshima University Hospital
| | - Yoshifumi Oku
- Division of Radiology, Department of Clinical Technology, Kagoshima University Hospital
| | - Yasumasa Saigo
- Division of Radiology, Department of Clinical Technology, Kagoshima University Hospital
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Fleming C, O'Keeffe S, McDermott R, Dunne M, McClean B, León Vintró L. The influence of Acuros XB on dose volume histogram metrics and tumour control probability modelling in locally advanced non-small cell lung cancer. Phys Med 2020; 81:295-301. [PMID: 33349542 DOI: 10.1016/j.ejmp.2020.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/03/2020] [Accepted: 11/19/2020] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Radiation therapy plans are assessed using dose volume metrics derived from clinical toxicity and outcome data. In this study, plans for patients with locally advanced non-small cell lung cancer (LA-NSCLC) are examined in the context of the implementation of the Acuros XB (AXB) dose calculation algorithm focussing on the impact on common metrics. METHODS Volumetric modulated arc therapy (VMAT) plans were generated for twenty patients, using the Analytical Anisotropic Algorithm (AAA) and recalculated with AXB for both dose to water (Dw) and dose to medium (Dm). Standard dose volume histogram (DVH) metrics for both targets and organs-at-risk (OARs) were extracted, in addition to tumour control probability (TCP) for targets. RESULTS Mean dose to the planning target volume (PTV) was not clinically different between the algorithms (within ±1.1 Gy) but differences were seen in the minimum dose, D99% and D98% as well as for conformity and homogeneity metrics. A difference in TCP was seen for AXBDm plans versus both AXBDw and AAA plans. No clinically relevant differences were seen in the lung metrics. For point doses to spinal cord and oesophagus, the AXBDm values were lower than AXBDw, by up to 1.0 Gy. CONCLUSION Normalisation of plans to the mean/median dose to the target does not need to be adjusted when moving from AAA to AXB. OAR point doses may decrease by up to 1 Gy with AXBDm, which can be accounted for in clinical planning. Other OAR metrics do not need to be adjusted.
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Affiliation(s)
- Cathy Fleming
- Dept. of Physics, St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland; UCD School of Physics, University College Dublin, Dublin, Ireland.
| | - Serena O'Keeffe
- Dept. of Physics, St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland; UCD School of Physics, University College Dublin, Dublin, Ireland
| | - Ronan McDermott
- Dept. of Radiation Oncology, St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland
| | - Mary Dunne
- Dept. of Radiation Oncology, St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland
| | - Brendan McClean
- Dept. of Physics, St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland
| | - Luis León Vintró
- UCD School of Physics, University College Dublin, Dublin, Ireland
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Dose volume histogram metrics and tumour control probability modelling in locally advanced non-small-cell lung cancer: average intensity dataset versus individual four-dimensional CT phases. JOURNAL OF RADIOTHERAPY IN PRACTICE 2020. [DOI: 10.1017/s146039692000076x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAim:This work compares dose-volume constraints (DVCs) and tumour control predictions based on the average intensity projection (AVIP) to those on each phase of the four-dimensional computed tomography.Materials and methods:In this prospective study plans generated on an AVIP for nine patients with locally advanced non-small-cell lung cancer were recalculated on each phase. Dose-volume histogram (DVH) metrics extracted and tumour control probabilities (TCP) were calculated. These were evaluated by Bland–Altman analysis and Pearson Correlation.Results:The largest difference between clinical target volume (CTV) on the individual phases and the internal CTV (iCTV) on the AVIP was seen for the smallest volume. For the planning target volume, the mean of each metric across all phases is well represented by the AVIP value. For most patients, TCPs from individual phases are representative of that on the AVIP. Organ at risk metrics from the AVIP are similar to those seen across all phases.Findings:Utilising traditional DVH metrics on an AVIP is generally valid, however, additional investigation may be required for small target volumes in combination with large motion as the differences between the values on the AVIP and any given phase may be significant.
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Fogliata A, Esposito E, Paganini L, Reggiori G, Tomatis S, Scorsetti M, Cozzi L. The impact of scanning data measurements on the Acuros dose calculation algorithm configuration. Radiat Oncol 2020; 15:169. [PMID: 32650815 PMCID: PMC7350585 DOI: 10.1186/s13014-020-01610-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/02/2020] [Indexed: 11/24/2022] Open
Abstract
Background Many dose calculation algorithms for radiotherapy planning need to be configured for each clinical beam using pre-defined measurements. An optimization process adjusts the physical parameters able to estimate the energy released in the medium in any geometrical condition. This work investigates the impact of measured input data quality on the configuration of the type “c” Acuros-XB dose calculation algorithm in the Eclipse (Varian Medical Systems) treatment planning system. Methods Different datasets were acquired with the BeamScan water phantom (PTW) to configure 6 MV beams, for both flattened (6X) and flattening filter free mode (6FFF) for a Varian TrueBeam: (i) a correct dataset measured using a Semiflex-3D ion chamber, (ii) a set in missing lateral scatter conditions (MLS), (iii) a set with incorrect effective point of measurement (EPoM), (iv) sets acquired with PinPoint-3D chamber, DiodeP, microDiamond detectors. The Acuros-XB dose calculation algorithm (version 15.6) was configured using the reference dataset, the sets measured with the different detectors, with intentional errors, and using the representative beam data (RBD) made available by the vendor. The physical parameters obtained from each optimization process (spectrum, mean radial energy, electron contamination), were analyzed and compared. Calculated data were finally compared against the input and reference measurements. Results Concerning the physical parameters, the configurations presenting the largest differences were the MLS conditions (mean radial energy) and the incorrect EPoM (electron contamination). The calculation doses relative to the input data present low accuracy, with mean differences > 2% in some conditions. The PinPoint-3D ion chamber presented lower accuracy for the 6FFF beam. Regarding the RBD, calculations compared well with the input data used for the configuration, but not with the reference data. Conclusion The MLS conditions and the incorrect setting of the EPoM lead to erroneous configurations and should be avoided. The choice of an appropriate detector is important. Whenever the representative beam data is used, a careful check under more clinical geometrical conditions is advised.
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Affiliation(s)
- A Fogliata
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.
| | - E Esposito
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - L Paganini
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - G Reggiori
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - S Tomatis
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - M Scorsetti
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Milan-Pieve Emanuele, Italy
| | - L Cozzi
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Milan-Pieve Emanuele, Italy
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Xing Y, Zhang Y, Nguyen D, Lin MH, Lu W, Jiang S. Boosting radiotherapy dose calculation accuracy with deep learning. J Appl Clin Med Phys 2020; 21:149-159. [PMID: 32559018 PMCID: PMC7484829 DOI: 10.1002/acm2.12937] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/09/2020] [Accepted: 05/11/2020] [Indexed: 12/26/2022] Open
Abstract
In radiotherapy, a trade‐off exists between computational workload/speed and dose calculation accuracy. Calculation methods like pencil‐beam convolution can be much faster than Monte‐Carlo methods, but less accurate. The dose difference, mostly caused by inhomogeneities and electronic disequilibrium, is highly correlated with the dose distribution and the underlying anatomical tissue density. We hypothesize that a conversion scheme can be established to boost low‐accuracy doses to high‐accuracy, using intensity information obtained from computed tomography (CT) images. A deep learning‐driven framework was developed to test the hypothesis by converting between two commercially available dose calculation methods: Anisotropic analytic algorithm (AAA) and Acuros XB (AXB). A hierarchically dense U‐Net model was developed to boost the accuracy of AAA dose toward the AXB level. The network contained multiple layers of varying feature sizes to learn their dose differences, in relationship to CT, both locally and globally. Anisotropic analytic algorithm and AXB doses were calculated in pairs for 120 lung radiotherapy plans covering various treatment techniques, beam energies, tumor locations, and dose levels. For each case, the CT and the AAA dose were used as the input and the AXB dose as the “ground‐truth” output, to train and test the model. The mean squared errors (MSEs) and gamma passing rates (2 mm/2% & 1 mm/1%) were calculated between the boosted AAA doses and the “ground‐truth” AXB doses. The boosted AAA doses demonstrated substantially improved match to the “ground‐truth” AXB doses, with average (± s.d.) gamma passing rate (1 mm/1%) 97.6% (±2.4%) compared to 87.8% (±9.0%) of the original AAA doses. The corresponding average MSE was 0.11(±0.05) vs 0.31(±0.21). Deep learning is able to capture the differences between dose calculation algorithms to boost the low‐accuracy algorithms. By combining a less accurate dose calculation algorithm with a trained deep learning model, dose calculation can potentially achieve both high accuracy and efficiency.
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Affiliation(s)
- Yixun Xing
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - You Zhang
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Dan Nguyen
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Mu-Han Lin
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Weiguo Lu
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Steve Jiang
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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Clinical implication in the use of the AAA algorithm versus the AXB in nasopharyngeal carcinomas by comparison of TCP and NTCP values. Radiat Oncol 2020; 15:150. [PMID: 32532351 PMCID: PMC7291676 DOI: 10.1186/s13014-020-01591-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 06/03/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose Retrospective analysis of volumetric modulated arc therapy treatment plans to investigate qualitative, possible, clinical consequences of the use of AAA versus AXB in nasopharyngeal cancer (NPC) cases. Methods The dose distribution of 26 treatment plans, produced using RapidArc technique and AAA algorithm, were recalculated using AXB and the same number of monitor units provided by AAA and clinically delivered to each patient. The potential clinical effect of dosimetric differences in the planning target volume (PTV) and in organs at risk (OAR) were evaluated by comparing TCP and NTCP values. The Wilcoxon Signed Rank test was used for statistical comparison of all results obtained from the use of the two algorithms. Results The poorer coverage of the PTV, with higher prescribed dose, was reflected in the TCP, which was significantly lower when AXB was used, the median value was 81.55% (range: 74.90, 88.60%) and 84.10% (range: 77.70, 89.90%) for AAA (p < 0.001). OAR mean dose was lower in the AXB recalculated plan than the AAA plan and the difference was statistically significant for all the structures. The NTCP for developing mandible necrosis showed the largest median percentage difference between AAA and AXB (56.6%), the NTCP of risk for larynx edema of Grade ≥ 2 followed with 12.2%. Conclusions Differences in dose distribution of NPC treatment plans recalculated with AXB are of clinical significance in those situations where the PTV and OAR involve air or bone, media in which AXB has been shown to more accurately represent the true dose distribution. The availability of AXB algorithm could improve patient dose estimation, increasing the data consistency of clinical trials.
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Chung JH, Chun M, Kim JI, Park JM, Shin KH. Three-dimensional versus four-dimensional dose calculation for breast intensity-modulated radiation therapy. Br J Radiol 2020; 93:20200047. [PMID: 32187503 PMCID: PMC10993216 DOI: 10.1259/bjr.20200047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/05/2020] [Accepted: 03/13/2020] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE To analyze the effect of intra- and interfractional motion during breast intensity modulated radiation therapy (IMRT) by calculating dose distribution based on four-dimensional computed tomography (4DCT). METHODS 20 patients diagnosed with left breast cancer were enrolled. Three-dimensional CT (3DCT) along with 10 phases of 4DCT were collected for each patient, with target volumes independently delineated on both 3DCT and all phases of 4DCT. IMRT plans were generated based on 3DCT (43.2 Gy in 16 fractions). The plan parameters for each segment were split into phases based on time duration estimates for each respiratory phase, with phase-specific dose distributions calculated and summated (4D-calculated dose). The procedure is repeated for 16 fractionations by randomly allocating starting phase using random-number generation to simulate interfractional discrepancy caused by different starting phase. Comparisons of plan quality between the original and 4D-calculated doses were analyzed. RESULTS There was a significant distortion in 4D-calculated dose induced by respiratory motion in terms of conformity and homogeneity index compared to those of the original 3D plan. Mean doses of the heart and the ipsilateral lung were significantly higher in the 4D-calculated doses compared to those of the original 3D plan (0.34 Gy, p = 0.010 and 0.59 Gy, p < 0.001), respectively). The mean internal mammary lymph node (IMN) dose was significantly greater in the 4D-calculated plan, compared to the original 3D plan (1.42 Gy, p < 0.001). CONCLUSIONS IMN doses should be optimized during the dose-calculation for the free-breathing left breast IMRT. ADVANCES IN KNOWLEDGE The interplay effect between respiratory motion and multileaf collimator modulation caused discrepancies in dose distribution, particularly in IMN.
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Affiliation(s)
- Joo-Hyun Chung
- Department of Radiation Oncology, Seoul National University
Hospital, Seoul, Republic
of Korea
| | - Minsoo Chun
- Department of Radiation Oncology, Seoul National University
Hospital, Seoul, Republic
of Korea
- Biomedical Research Institute, Seoul National University
College of Medicine, Seoul,
Republic of Korea
- Institute of Radiation Medicine, Seoul National University
Medical Research Center, Seoul,
Republic of Korea
| | - Jung-in Kim
- Department of Radiation Oncology, Seoul National University
Hospital, Seoul, Republic
of Korea
- Biomedical Research Institute, Seoul National University
College of Medicine, Seoul,
Republic of Korea
- Institute of Radiation Medicine, Seoul National University
Medical Research Center, Seoul,
Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University
Hospital, Seoul, Republic
of Korea
- Biomedical Research Institute, Seoul National University
College of Medicine, Seoul,
Republic of Korea
- Institute of Radiation Medicine, Seoul National University
Medical Research Center, Seoul,
Republic of Korea
- Robotics Research Laboratory for Extreme Environments, Advanced
Institutes of Convergence Technology,
Suwon, Republic of Korea
| | - Kyung Hwan Shin
- Department of Radiation Oncology, Seoul National University
Hospital, Seoul, Republic
of Korea
- Biomedical Research Institute, Seoul National University
College of Medicine, Seoul,
Republic of Korea
- Institute of Radiation Medicine, Seoul National University
Medical Research Center, Seoul,
Republic of Korea
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Mamesa S, Oonsiri S, Sanghangthum T, Yabsantia S, Suriyapee S. The impact of corrected field output factors based on IAEA/AAPM code of practice on small-field dosimetry to the calculated monitor unit in eclipse™ treatment planning system. J Appl Clin Med Phys 2020; 21:65-75. [PMID: 32237215 PMCID: PMC7286014 DOI: 10.1002/acm2.12855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 12/13/2020] [Accepted: 02/08/2020] [Indexed: 12/14/2022] Open
Abstract
The objective of this study was to investigate the effect of field output factors (FOFs) according to the current protocol for small-field dosimetry in conjunction to treatment planning system (TPS) commissioning. The calculated monitor unit (MU) for intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans in Eclipse™ TPS were observed. Micro ion chamber (0.01 CC) (CC01), photon field diode (shielded diode) (PFD), and electron field diode (unshielded diode) (EFD) were used to measure percentage depth doses, beam profiles, and FOFs from 1 × 1 cm2 to 10 × 10 cm2 field sizes of 6 MV photon beams. CC01 illustrated the highest percentage depth doses at 10 cm depth while EFD exhibited the lowest with the difference of 1.6% at 1 × 1 cm2 . CC01 also produced slightly broader penumbra, the difference with other detectors was within 1 mm. For uncorrected FOF of three detectors, the maximum percent standard deviation (%SD) was 5.4% at 1 × 1 cm2 field size. When the correction factors were applied, this value dropped to 2.7%. For the calculated MU in symmetric field sizes, beam commissioning group from uncorrected FOF demonstrated maximum %SD of 6.0% at 1 × 1 cm2 field size. This value decreased to 2.2% when the corrected FOF was integrated. For the calculated MU in IMRT-SRS plans, the impact of corrected FOF reduced the maximum %SD from 6.0% to 2.5% in planning target volume (PTV) less than 0.5 cm3 . Beam commissioning using corrected FOF also decreased %SD for VMAT-SRS plans, although it was less pronounced in comparison to other treatment planning techniques, since the %SD remained less than 2%. The use of FOFs based on IAEA/AAPM TRS 483 has been proven in this research to reduce the discrepancy of calculated MU among three beam commissioning datasets in Eclipse™ TPS. The dose measurement of both symmetric field and clinical cases comparing to the calculation illustrated the dependence of the types of detector commissioning and the algorithm of the treatment planning for small field size.
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Affiliation(s)
- Sammuel Mamesa
- Medical Physics Program, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sornjarod Oonsiri
- Division of Radiation Oncology, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Taweap Sanghangthum
- Medical Physics Program, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Division of Radiation Oncology, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Sumalee Yabsantia
- Medical Physics Program, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sivalee Suriyapee
- Medical Physics Program, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Division of Radiation Oncology, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
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Kumar L, Kishore V, Bhushan M, Dewan A, Yadav G, Raman K, Kumar G, Ahmad I, Chufal KS, Gairola M. Impact of acuros XB algorithm in deep-inspiration breath-hold (DIBH) respiratory techniques used for the treatment of left breast cancer. Rep Pract Oncol Radiother 2020; 25:507-514. [PMID: 32494224 DOI: 10.1016/j.rpor.2020.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 03/06/2020] [Accepted: 04/15/2020] [Indexed: 12/25/2022] Open
Abstract
Aim To investigate the impact of Acuros XB (AXB) algorithm in the deep-inspiration breath-hold (DIBH) technique used for treatment of left sided breast cancer. Background AXB may estimate better lung toxicities and treatment outcome in DIBH. Materials and Methods Treatment plans were computed using the field-in-field technique for a 6 MV beam in two respiratory phases - free breathing (FB) and DIBH. The AXB-calculations were performed under identical beam setup and the same numbers of monitor units as used for AAA-calculation. Results Mean Hounsfield units (HU), mass density (g/cc) and relative electron density were -782.1 ± 24.8 and -883.5 ± 24.9; 0.196 ± 0.025 and 0.083 ± 0.032; 0.218 ± 0.025 and 0.117 ± 0.025 for the lung in the FB and DIBH respiratory phase, respectively. For a similar target coverage (p > 0.05) in the DIBH respiratory phase between the AXB and AAA algorithm, there was a slight increase in organ at risk (OAR) dose for AXB in comparison to AAA, except for mean dose to the ipsilateral lung. AAA predicts higher mean dose to the ipsilateral lung and lesser V20Gy for the ipsilateral and common lung in comparison to AXB. The differences in mean dose to the ipsilateral lung were 0.87 ± 2.66 % (p > 0.05) in FB, and 1.01 ± 1.07% (p < 0.05) in DIBH, in V20Gy the differences were 1.76 ± 0.83% and 1.71 ± 0.82% in FB (p < 0.05), 3.34 ± 1.15 % and 3.24 ± 1.17 % in DIBH (p < 0.05), for the ipsilateral and common lung, respectively. Conclusion For a similar target volume coverage, there were important differences between the AXB and AAA algorithm for low-density inhomogeneity medium present in the DIBH respiratory phase for left sided breast cancer patients. DIBH treatment in conjunction with AXB may result in better estimation of lung toxicities and treatment outcome.
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Affiliation(s)
- Lalit Kumar
- Department of Applied Science & Humanities, Dr. A.P.J Abdul Kalam Technical University, Lucknow, India.,Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Vimal Kishore
- Department of Applied Science & Humanities, Bundelkhand Institute of Engineering & Technology, Jhansi, India
| | - Manindra Bhushan
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Abhinav Dewan
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Girigesh Yadav
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Kothanda Raman
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Gourav Kumar
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Irfan Ahmad
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Kundan S Chufal
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
| | - Munish Gairola
- Medical Physics Division & Radiation Oncology Department, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, India
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Dosimetric comparison of analytic anisotropic algorithm and Acuros XB algorithm in VMAT plans for high-grade glioma. Phys Med 2020; 73:73-82. [PMID: 32330814 DOI: 10.1016/j.ejmp.2020.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To investigate the dosimetric impact between the anisotropic analytical algorithm (AAA) and the Acuros XB (AXB) algorithm in volumetric-modulated arc therapy (VMAT) plans for high-grade glioma (HGG). METHODS We used a heterogeneous phantom to quantify the agreement between the measured and calculated doses from the AAA and from the AXB. We then analyzed 14 patients with HGG treated by VMAT, using the AAA. We newly created AXB plans for each corresponding AAA plan under the following conditions: (1) re-calculation for the same number of monitor units with an identical beam and leaf setup, and (2) re-optimization under the same conditions of dose constraints. The dose coverage for the planning target volume (PTV) was evaluated by dividing the coverage into the skull, air, and soft-tissue regions. RESULTS Compared to the results obtained with the AAA, the AXB results were in good agreement with the measured profiles. The dose differences in the PTV between the AAA and re-calculated AXB plans were large in the skull region contained in the target. The dose difference in the PTV in both types of plan was significantly correlated with the volume of the skull contained in the target (r = 0.71, p = 0.0042). A re-optimized AXB plan's dose difference was lower vs. the re-calculated AXB plan's. CONCLUSIONS We observed dose differences between the AAA and AXB plans, in particular in the cases in which the skull region of the target was large. Considering the phantom measurement results, the AXB algorithm should be used in VMAT plans for HGG.
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Cabanas ML, Yan C, Lalonde RJ, Heron DE, Huq MS. Which Dose Specification Should Be Used for NRG Radiation Therapy Trials: Dose-to-Medium or Dose-to-Water? Pract Radiat Oncol 2020; 10:e103-e110. [DOI: 10.1016/j.prro.2019.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/06/2019] [Accepted: 08/25/2019] [Indexed: 10/26/2022]
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