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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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2
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Kolacio MŠ, Rajlić D, Radojčić M, Radojčić ĐS, Obajdin N, Debeljuh DD, Jurković S. Dosimetric accuracy of three dose calculation algorithms for radiation therapy of in situ non-small cell lung carcinoma. Rep Pract Oncol Radiother 2022; 27:86-96. [PMID: 35402037 PMCID: PMC8989458 DOI: 10.5603/rpor.a2022.0013] [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: 11/09/2021] [Accepted: 01/19/2022] [Indexed: 11/25/2022] Open
Abstract
Background Study determines differences in calculated dose distributions for non-small cell lung carcinoma (NSC LC) patients. NSC LC cases were investigated, being the most common lung cancer treated by radiotherapy in our clinical practice. Materials and methods A retrospective study of 15 NSCLC patient dose distributions originally calculated using standard superposition (SS) and recalculated using collapsed cone (CC ) and Monte Carlo (MC) based algorithm expressed as dose to medium in medium (MCDm) and dose to water in medium (MCDw,) was performed so that prescribed dose covers at least 99% of the gross target volume (GTV). Statistical analysis was performed for differences of conformity index (CI), heterogeneity index (HI), gradient index (GI), dose delivered to 2% of the volume (D2%), mean dose (Dmean) and percentage of volumes covered by prescribed dose (V70Gy). For organs at risk (OARs), Dmean and percentage of volume receiving 20 Gy and 5Gy (V20Gy, V5Gy) were analysed. Results Statistically significant difference for GTVs was observed between MCDw and SS algorithm in mean dose only. For planning target volumes (PTVs), statistically significant differences were observed in prescribed dose coverage for CC, MCDm and MCDw. The differences in mean CI value for the CC algorithm and mean HI value for MCDm and MCDw were statistically significant. There is a statistically significant difference in the number of MUs for MCDm and MCDw compared to SS. Conclusion All investigated algorithms succeed in managing the restrictive conditions of the clinical goals. This study shows the drawbacks of the CC algorithm compared to other algorithms used.
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Affiliation(s)
| | - David Rajlić
- Medical Physics Department, Clinical Hospital Center Rijeka, Rijeka, Croatia
| | - Milan Radojčić
- Clinic for Radiotherapy and Oncology, Clinical Hospital Center Rijeka, Rijeka, Croatia
| | - Đeni Smilović Radojčić
- Medical Physics Department, Clinical Hospital Center Rijeka, Rijeka, Croatia.,Department of Medical Physics and Biophysics, University of Rijeka Faculty of Medicine, Rijeka, Croatia
| | - Nevena Obajdin
- Medical Physics Department, Clinical Hospital Center Rijeka, Rijeka, Croatia
| | - Dea Dundara Debeljuh
- Medical Physics Department, Clinical Hospital Center Rijeka, Rijeka, Croatia.,Department of Medical Physics and Biophysics, University of Rijeka Faculty of Medicine, Rijeka, Croatia.,Radiology Department, General Hospital Pula, Pula, Croatia
| | - Slaven Jurković
- Medical Physics Department, Clinical Hospital Center Rijeka, Rijeka, Croatia.,Department of Medical Physics and Biophysics, University of Rijeka Faculty of Medicine, Rijeka, Croatia
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3
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Jurado-Bruggeman D, Muñoz-Montplet C, Hernandez V, Saez J, Fuentes-Raspall R. Impact of the dose quantity used in MV photon optimization on dose distribution, robustness, and complexity. Med Phys 2021; 49:648-665. [PMID: 34855988 DOI: 10.1002/mp.15389] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/09/2021] [Accepted: 11/18/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Convolution/superposition algorithms used in megavoltage (MV) photon radiotherapy model radiation transport in water, yielding dose to water-in-water (Dw,w ). Advanced algorithms constitute a step forward, but their dose distributions in terms of dose to medium-in-medium (Dm,m ) or dose to water-in-medium (Dw,m ) can be problematic when used in plan optimization due to their different dose responses to some atomic composition heterogeneities. Failure to take this into account can lead to undesired overcorrections and thus to unnoticed suboptimal and unrobust plans. Dose to reference-like medium (Dref,m* ) was recently introduced to overcome these limitations while ensuring accurate transport. This work evaluates and compares the performance of these four dose quantities in planning target volume (PTV)-based optimization. METHODS We considered three cases with heterogeneities inside the PTV: virtual phantom with water surrounded by bone; head and neck; and lung. These cases were planned with volumetric modulated arc therapy (VMAT) technique, optimizing with the same setup and objectives for each dose quantity. We used different algorithms of the Varian Eclipse treatment planning system (TPS): Acuros XB (AXB) for Dm,m and Dw,m , and Analytical Anisotropic Algorithm (AAA) for Dw,w . Dref,m* was obtained from Dm,m distributions using an in-house software considering water as the reference medium (Dw,m* ). The optimization process consisted of: (1) common first optimization, (2) dose distribution computed for each quantity, (3) re-optimization, and (4) final calculation for each dose quantity. The dose distribution, robustness to patient setup errors, and complexity of the plans were analyzed and compared. RESULTS The quantities showed similar dose distributions after the optimization but differed in terms of plan robustness. The cases with soft tissue and high-density heterogeneities followed the same pattern. For AXB Dm,m , cold regions appeared in the heterogeneities after the first optimization. They were compensated in the second optimization through local fluence increases, but any positional mismatch impacted robustness, with clinical target volume (CTV) variations from the nominal scenario around +3% for bone and up to +7% for metal. For AXB Dw,m the pattern was inverse (hot regions compensated by fluence decreases) and more pronounced, with CTV dose variations around -7% for bone and up to -17% for metal. Neither AXB Dw,m* nor AAA Dw,w presented these dose inhomogeneities, which resulted in more robust plans. However, Dw,w differed markedly from the other quantities in the lung case because of its lower radiation transport accuracy. AXB Dm,m was the most complex of the four dose quantities and AXB Dw,m* the least complex, though we observed no major differences in this regard. CONCLUSIONS The dose quantity used in MV photon optimization can affect plan robustness. Dw,w distributions from convolution/superposition algorithms are robust but may not provide sufficient radiation transport accuracy in some cases. Dm,m and Dw,m from advanced algorithms can compromise robustness because their different responses to some composition heterogeneities introduce additional fluence compensations. Dref,m* offers advantages in plan optimization and evaluation, producing accurate and robust plans without increasing complexity. Dref,m* can be easily implemented as a built-in feature of the TPS and can facilitate and simplify the treatment planning process when using advanced algorithms. Final reporting can be kept in Dm,m or Dw,m for clinical correlations.
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Affiliation(s)
- Diego Jurado-Bruggeman
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Girona, Spain
| | - Carles Muñoz-Montplet
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Girona, Spain.,Department of Medical Sciences, University of Girona, Girona, Spain
| | - Victor Hernandez
- Department of Medical Physics, Hospital Universitari Sant Joan de Reus, IISPV, Tarragona, Spain.,Universitat Rovira i Virgili, Tarragona, Spain
| | - Jordi Saez
- Department of Radiation Oncology, Hospital Clínic de Barcelona, Barcelona, Spain
| | - Rafael Fuentes-Raspall
- Department of Medical Sciences, University of Girona, Girona, Spain.,Radiation Oncology Department, Institut Català d'Oncologia, Girona, Spain
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4
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Srivastava RP, Basta K, De Gersem W, De Wagter C. A comparative analysis of Acuros XB and the analytical anisotropic algorithm for volumetric modulation arc therapy. REPORTS OF PRACTICAL ONCOLOGY AND RADIOTHERAPY : JOURNAL OF GREATPOLAND CANCER CENTER IN POZNAN AND POLISH SOCIETY OF RADIATION ONCOLOGY 2021; 26:481-488. [PMID: 34277105 PMCID: PMC8281916 DOI: 10.5603/rpor.a2021.0050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/23/2021] [Indexed: 11/25/2022]
Abstract
Background This study aimed to verify the dosimetric impact of Acuros XB (AXB) (AXB, Varian Medical Systems Palo Alto CA, USA), a two model-based algorithm, in comparison with Anisotropic Analytical Algorithm (AAA ) calculations for prostate, head and neck and lung cancer treatment by volumetric modulated arc therapy (VMAT ), without primary modification to AA. At present, the well-known and validated AA algorithm is clinically used in our department for VMAT treatments of different pathologies. AXB could replace it without extra measurements. The treatment result and accuracy of the dose delivered depend on the dose calculation algorithm. Materials and method Ninety-five complex VMAT plans for different pathologies were generated using the Eclipse version 15.0.4 treatment planning system (TPS). The dose distributions were calculated using AA and AXB (dose-to-water, AXBw and dose-to-medium, AXBm), with the same plan parameters for all VMAT plans. The dosimetric parameters were calculated for each planning target volume (PTV) and involved organs at risk (OA R). The patient specific quality assurance of all VMAT plans has been verified by Octavius®-4D phantom for different algorithms. Results The relative differences among AA, AXBw and AXBm, with respect to prostate, head and neck were less than 1% for PTV D95%. However, PTV D95% calculated by AA tended to be overestimated, with a relative dose difference of 3.23% in the case of lung treatment. The absolute mean values of the relative differences were 1.1 ± 1.2% and 2.0 ± 1.2%, when comparing between AXBw and AA, AXBm and AA, respectively. The gamma pass rate was observed to exceed 97.4% and 99.4% for the measured and calculated doses in most cases of the volumetric 3D analysis for AA and AXBm, respectively. Conclusion This study suggests that the dose calculated to medium using AXBm algorithm is better than AAA and it could be used clinically. Switching the dose calculation algorithm from AA to AXB does not require extra measurements.
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Affiliation(s)
- Raju P Srivastava
- Radiotherapy Association Meuse Picardie, Centre Hospitalier Mouscron, Mouscron, Belgium.,Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium
| | - K Basta
- Radiotherapy Association Meuse Picardie, Centre Hospitalier Mouscron, Mouscron, Belgium
| | - Werner De Gersem
- Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium.,Department of Radiation Oncology and Experimental Cancer Research, Ghent University, Belgium
| | - Carlos De Wagter
- Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium.,Department of Radiation Oncology and Experimental Cancer Research, Ghent University, Belgium
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5
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Muñoz-Montplet C, Fuentes-Raspall R, Jurado-Bruggeman D, Agramunt-Chaler S, Onsès-Segarra A, Buxó M. Dosimetric Impact of Acuros XB Dose-to-Water and Dose-to-Medium Reporting Modes on Lung Stereotactic Body Radiation Therapy and Its Dependency on Structure Composition. Adv Radiat Oncol 2021; 6:100722. [PMID: 34258473 PMCID: PMC8256186 DOI: 10.1016/j.adro.2021.100722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/22/2021] [Accepted: 05/07/2021] [Indexed: 11/28/2022] Open
Abstract
Purpose Our purpose was to assess the dosimetric effect of switching from the analytical anisotropic algorithm (AAA) to Acuros XB (AXB), with dose-to-medium (Dm) and dose-to-water (Dw) reporting modes, in lung stereotactic body radiation therapy patients and determine whether planning-target-volume (PTV) dose prescriptions and organ-at-risk constraints should be modified under these circumstances. Methods and Materials We included 54 lung stereotactic body radiation therapy patients. We delineated the PTV, the ipsilateral lung, the contralateral lung, the heart, the spinal cord, the esophagus, the trachea, proximal bronchi, the ribs, and the great vessels. We performed dose calculations with AAA and AXB, then compared clinically relevant dose-volume parameters. Paired t tests were used to analyze differences of means. We propose a method, based on the composition of the involved structures, for predicting differences between AXB Dw and Dm calculations. Results The largest difference between the algorithms was 4%. Mean dose differences between AXB Dm and AXB Dw depended on the average composition of the volumes. Compared with AXB, AAA underestimated all PTV dose-volume parameters (-0.7 Gy to -0.1 Gy) except for gradient index, which was significantly higher (4%). It also underestimated V5 of the contralateral lung (-0.3%). Significant differences in near-maximum doses (D2) to the ribs were observed between AXB Dm and AAA (1.7%) and between AXB Dw and AAA (-1.6%). AAA-calculated D2 was slightly higher in the remaining organs at risk. Conclusions Differences between AXB and AAA are below the threshold of clinical detectability (5%) for most patients. For a small subgroup, the difference in maximum doses to the ribs between AXB Dw and AXB Dm may be clinically significant. The differences in dose volume parameters between AXB Dw and AXB Dm can be predicted with reference to structure composition.
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Affiliation(s)
- Carles Muñoz-Montplet
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Avda. França s/n, 17007 Girona, Spain.,Department of Medical Sciences, University of Girona, C/Emili Grahit 77, 17003 Girona, Spain
| | - Rafael Fuentes-Raspall
- Department of Medical Sciences, University of Girona, C/Emili Grahit 77, 17003 Girona, Spain.,Radiation Oncology Department, Institut Català d'Oncologia, Avda. França s/n, 17007 Girona, Spain
| | - Diego Jurado-Bruggeman
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Avda. França s/n, 17007 Girona, Spain
| | - Sebastià Agramunt-Chaler
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Avda. França s/n, 17007 Girona, Spain
| | - Albert Onsès-Segarra
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Avda. França s/n, 17007 Girona, Spain
| | - Maria Buxó
- Girona Biomedical Research Institute (IDIBGI), Parc Hospitalari Martí i Julià, Edifici M2, 17190, Salt, Spain
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Report dose-to-medium in clinical trials where available; a consensus from the Global Harmonisation Group to maximize consistency. Radiother Oncol 2021; 159:106-111. [PMID: 33741471 DOI: 10.1016/j.radonc.2021.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/05/2021] [Accepted: 03/06/2021] [Indexed: 11/22/2022]
Abstract
PURPOSE To promote consistency in clinical trials by recommending a uniform framework as it relates to radiation transport and dose calculation in water versus in medium. METHODS The Global Quality Assurance of Radiation Therapy Clinical Trials Harmonisation Group (GHG; www.rtqaharmonization.org) compared the differences between dose to water in water (Dw,w), dose to water in medium (Dw,m), and dose to medium in medium (Dm,m). This was done based on a review of historical frameworks, existing literature and standards, clinical issues in the context of clinical trials, and the trajectory of radiation dose calculations. Based on these factors, recommendations were developed. RESULTS No framework was found to be ideal or perfect given the history, complexity, and current status of radiation therapy. Nevertheless, based on the evidence available, the GHG established a recommendation preferring dose to medium in medium (Dm,m). CONCLUSIONS Dose to medium in medium (Dm,m) is the preferred dose calculation and reporting framework. If an institution's planning system can only calculate dose to water in water (Dw,w), this is acceptable.
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Evaluation of clinical implications in the use of dose to water versus dose to medium by using NTCP and TCP models for urinary bladder tumours. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2021. [DOI: 10.2478/pjmpe-2021-0003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Purpose: To analyze the dosimetric and radiobiological differences between dose to water versus dose to medium for patients with carcinoma of the urinary bladder.
Materials and Methods: 15 patients with cancer of urinary bladder were selected for the study. VMAT plans were generated for each patient. The dose distributions were calculated in the modes dose to water and to medium with the Monaco treatment planning system. A dosimetric comparative analysis has been made between the two modes of planning in this study. Subsequently, NTCP and TCP were determined for OARs and targets respectively.
Results: The mean dose to 2 cc of the rectum, small bowel, left and right femoral heads respectively was higher by 0.8, 1.2, 2.7, and 2.2% for the dose to water calculation. Similarly, the mean dose to D2, D50, and D98 for PTV was higher by 0.4, 0.3, and 0.3% for dose to water calculation. Such small dose differences had little effect on the values of TCP and NTCP.
Conclusion: For patients with the urinary bladder there were very small differences between results between calculations carried out in dose to medium and dose to water modes.
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Younes T, Chauvin M, Delbaere A, Labour J, Fonteny V, Simon L, Fares G, Vieillevigne L. Towards the standardization of the absorbed dose report mode in high energy photon beams. Phys Med Biol 2021; 66:045009. [PMID: 33296874 DOI: 10.1088/1361-6560/abd22c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The benefits of using an algorithm that reports absorbed dose-to-medium have been jeopardized by the clinical experience and the experimental protocols that have mainly relied on absorbed dose-to-water. The aim of the present work was to investigate the physical aspects that govern the dosimetry in heterogeneous media using Monte Carlo method and to introduce a formalism for the experimental validation of absorbed dose-to-medium reporting algorithms. Particle fluence spectra computed within the sensitive volume of two simulated detectors (T31016 Pinpoint 3D ionization chamber and EBT3 radiochromic film) placed in different media (water, RW3, lung and bone) were compared to those in the undisturbed media for 6 MV photon beams. A heterogeneity correction factor that takes into account the difference between the detector perturbation in medium and under reference conditions as well as the stopping-power ratios was then derived for all media using cema calculations. Furthermore, the different conversion approaches and Eclipse treatment planning system algorithms were compared against the Monte Carlo absorbed dose reports. The detectors electron fluence perturbation in RW3 and lung media were close to that in water (≤1.5%). However, the perturbation was greater in bone (∼4%) and impacted the spectral shape. It was emphasized that detectors readings should be corrected by the heterogeneity correction factor that ranged from 0.932 in bone to 0.985 in lung. Significant discrepancies were observed between all the absorbed dose reports and conversions, especially in bone (exceeding 10%) and to a lesser extent in RW3. Given the ongoing advances in dose calculation algorithms, it is essential to standardize the absorbed dose report mode with absorbed dose-to-medium as a favoured choice. It was concluded that a retrospective conversion should be avoided and switching from absorbed dose-to-water to absorbed dose-to-medium reporting algorithm should be carried out by a direct comparison of both algorithms.
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Affiliation(s)
- Tony Younes
- Department of Medical Physics, Institut Claudius Regaud-Institut Universitaire du Cancer de Toulouse Oncopole, 1 avenue Irène Joliot Curie, F-31059 Toulouse Cedex 9, France. Centre de Recherche et de Cancérologie de Toulouse, UMR1037 INSERM-Université Toulouse 3-ERL5294 CNRS, 2 avenue Hubert Curien, F-31037 Toulouse Cedex 1, France. Laboratoire de 'Mathématiques et Applications', Unité de recherche 'Mathématiques et Modélisation', Centre d'analyses et de recherche, Faculté des sciences, Université Saint-Joseph, Beyrouth 1104 2020, Lebanon
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Kolacio MŠ, Brkić H, Faj D, Radojčić ĐS, Rajlić D, Obajdin N, Jurković S. Validation of two calculation options built in Elekta Monaco Monte Carlo based algorithm using MCNP code. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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10
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Jurado-Bruggeman D, Muñoz-Montplet C, Vilanova JC. A new dose quantity for evaluation and optimisation of MV photon dose distributions when using advanced algorithms: proof of concept and potential applications. Phys Med Biol 2020; 65:235020. [PMID: 32906107 DOI: 10.1088/1361-6560/abb6bc] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Advanced algorithms used in MV photon radiotherapy model radiation transport in any media. They represent a step forward but introduce new uncertainties and questions, including whether to report the doses to water (Dw,m) or medium (Dm,m) voxels, and the impact of fluence changes introduced by surrounding media. These aspects can compromise consistency between both reporting modes and with previous algorithms in which clinical experience is based. This study introduces a new dose quantity, the dose-to-reference-like medium, to overcome the aforementioned shortcomings. It is linked to a reference medium, water in this study (Dw,m*), and defined as the absorbed dose in a voxel of this reference medium surrounded by a reference-like medium with the same radiation transport characteristics as the original one. We propose to derive Dw,m* distributions by post-processing Dw,m or Dm,m applying a correction factor (CF) to each voxel which depends on its composition. We present and justify a simple and straightforward method to obtain CFs that only involves two phantoms with the same density: one with the considered composition and the other with that of the reference medium. A proof of concept was performed in a clinical environment for Acuros XB (AXB) advanced algorithm and 6 MV photon beams. The CFs were derived for the tissues characterised in Acuros. Dw,m* was compared to Dw,m, Dm,m, and Dw,w from AAA analytical algorithm for some virtual and clinical cases. All the previous quantities presented limitations that can be solved by Dw,m*. This new quantity allows the applicability of evaluation parameters, traceability to clinical experience, and isolation of heterogeneity effects to identify optimum plans, offering useful characteristics for plan evaluation and optimisation in clinical practice. Additionally, it also has potential applications in automated treatment planning and multi-centre activities such as clinical trials, audits, benchmarking, and shared models for automation.
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Affiliation(s)
- Diego Jurado-Bruggeman
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Girona, Spain
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Dosimetric impact of switching from AAA to Acuros dose-to-water and dose-to-medium for RapidArc plans of nasopharyngeal carcinomas. Cancer Radiother 2020; 24:842-850. [PMID: 33153875 DOI: 10.1016/j.canrad.2020.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/12/2020] [Accepted: 05/16/2020] [Indexed: 11/22/2022]
Abstract
PURPOSE This work aims to evaluate the dosimetric consequences of replacing the Anisotropic Analytical Algorithm (AAA) by Acuros XB (AXB), dose-to-water (Dw) or dose-to-medium (Dm), for RapidArc plans of nasopharyngeal carcinomas (NPC). MATERIALS AND METHODS Seventeen NPC plans created with AAA (v15.6) were recalculated with AXB (v15.6) Dw and Dm. The dose-volume parameters to the planning target volumes (PTV) and relevant organs at risk (OAR) were compared. The high dose PTV was divided into bone, air and tissue components and the comparison was performed for each of them. RESULTS AXB Dw revealed no significant differences in the PTVs compared to AAA. Lower values were observed to spinal cord, brainstem, oral cavity and parotids (0.5% to 2.3%), and higher values to cochleas (up to 5.4%) and mandible (up to 6.7%). AXB Dm predicted lower values than AAA for all PTVs and OARs (2.0% to 6.1%). For the bone PTV subvolume, AXB Dw and Dm predicted respectively higher (2.4%) and lower (2.2% to 3.4%) values. No significant differences were noted in air. AXB predicted lower values than AAA in soft tissues (0.4% to 1.6%). The largest difference was found to the mandible V60Gy parameter, with median differences of 6.7% for AXB Dw and -6.0% for AXB Dm. CONCLUSION Significant dose differences are expected when switching from AAA to AXB in NPC cases. The dose prescriptions and the tolerance limits for some OARs, especially those of high density, may need to be adjusted depending on the selected dose calculation algorithm and reporting mode.
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Radojcic DS, Casar B, Rajlic D, Kolacio MS, Mendez I, Obajdin N, Debeljuh DD, Jurkovic S. Experimental validation of Monte Carlo based treatment planning system in bone density equivalent media. Radiol Oncol 2020; 54:495-504. [PMID: 32936784 PMCID: PMC7585341 DOI: 10.2478/raon-2020-0051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/09/2020] [Indexed: 11/20/2022] Open
Abstract
Introduction Advanced, Monte Carlo (MC) based dose calculation algorithms, determine absorbed dose as dose to medium-in-medium (Dm,m) or dose to water-in-medium (Dw,m). Some earlier studies identified the differences in the absorbed doses related to the calculation mode, especially in the bone density equivalent (BDE) media. Since the calculation algorithms built in the treatment planning systems (TPS) should be dosimetrically verified before their use, we analyzed dose differences between two calculation modes for the Elekta Monaco TPS. We compared them with experimentally determined values, aiming to define a supplement to the existing TPS verification methodology. Materials and methods In our study, we used a 6 MV photon beam from a linear accelerator. To evaluate the accuracy of the TPS calculation approaches, measurements with a Farmer type chamber in a semi-anthropomorphic phantom were compared to those obtained by two calculation options. The comparison was made for three parts of the phantom having different densities, with a focus on the BDE part. Results Measured and calculated doses were in agreement for water and lung equivalent density materials, regardless of the calculation mode. However, in the BDE part of the phantom, mean dose differences between the calculation options ranged from 5.7 to 8.3%, depending on the method used. In the BDE part of the phantom, neither of the two calculation options were consistent with experimentally determined absorbed doses. Conclusions Based on our findings, we proposed a supplement to the current methodology for the verification of commercial MC based TPS by performing additional measurements in BDE material.
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Affiliation(s)
- Djeni Smilovic Radojcic
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
- Department of Medical Physics and Biophysics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Bozidar Casar
- Department for Dosimetry and Quality of Radiological procedures, Institute of Oncology Ljubljana, Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - David Rajlic
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
| | | | - Ignasi Mendez
- Department for Dosimetry and Quality of Radiological procedures, Institute of Oncology Ljubljana, Ljubljana, Slovenia
| | - Nevena Obajdin
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
| | - Dea Dundara Debeljuh
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
- General Hospital Pula, Radiology Department, Pula, Croatia
| | - Slaven Jurkovic
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
- Department of Medical Physics and Biophysics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Improving the accuracy of converting dose to medium to dose to water algorithms in small megavoltage photon fields in dose to medium based treatment planning systems. Phys Med 2020; 71:62-70. [DOI: 10.1016/j.ejmp.2020.01.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/17/2020] [Accepted: 01/26/2020] [Indexed: 11/18/2022] Open
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Vaniqui A, Walters BR, Fonseca GP, Verhaegen F. Dose to water versus dose to medium from cavity theory applied to small animal irradiation with kilovolt x-rays. Phys Med Biol 2019; 64:165001. [PMID: 31252419 DOI: 10.1088/1361-6560/ab2db1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Dose reporting is a matter of concern in the preclinical field as the different dose descriptors dose-to-water-in-medium [Formula: see text] and dose-to-medium-in-medium [Formula: see text] coexist. For kV photons differences between both quantities are expected to be amplified due to photon energy absorption coefficients differences for different media, and could represent a limiting factor for accurate translation of pre-clinical research into clinical trials. The main goal of this study was to analyse the relationship between [Formula: see text] and [Formula: see text] for kV irradiation of small animals, using different flavours of the intermediate cavity theory (ICT). Irradiations of mathematical phantoms and a mouse CT scan, both with different voxel sizes and materials, were investigated. A modified version of the Monte Carlo code DOSXYZnrc was used to derive [Formula: see text] and convert to [Formula: see text] using ICT. Local photon spectra were generated in different regions of the mouse. Depending on energy and cavity size, which we equate to the voxel size, [Formula: see text] ranged from 0.68 to 4.37 times [Formula: see text]. Higher kV energy combined with very small cavity sizes yielded decreased [Formula: see text] in comparison to [Formula: see text]; this behaviour was reversed for larger cavities combined with lower kV energies. Hence, the impact of the cavity dimensions on estimated [Formula: see text] is significant on pre-clinical kV beams. [Formula: see text] and [Formula: see text] in the ex vivo male mouse were found to differ by -29% to 286%. Caution is advised when using the ICT due to a lack of consensus on weighting factor (d-parameter) deriving methods; for the same irradiation conditions, different d-values affected [Formula: see text] up to 20%. Pre-clinically, such divergence between dose descriptors could enable biological damage. The abiding debate over which quantity to favour is foreseen to linger while it is unclear which quantity correlates better with the biological effects of ionizing irradiation: preclinical radiotherapy might represent an ideal platform for measurement-based studies to settle this fundamental question. Finally, dose distribution comparisons require caution and should use the same reporting quantity.
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Affiliation(s)
- Ana Vaniqui
- Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
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Radojcic ĐS, Rajlic D, Casar B, Kolacio MS, Obajdin N, Faj D, Jurkovic S. Evaluation of two-dimensional dose distributions for pre-treatment patient-specific IMRT dosimetry. Radiol Oncol 2018; 52:346-352. [PMID: 30210046 PMCID: PMC6137356 DOI: 10.2478/raon-2018-0019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/13/2018] [Indexed: 11/22/2022] Open
Abstract
Background The accuracy of dose calculation is crucial for success of the radiotherapy treatment. One of the methods that represent the current standard for patient-specific dosimetry is the evaluation of dose distributions measured with an ionization chamber array inside a homogeneous phantom using gamma method. Nevertheless, this method does not replicate the realistic conditions present when a patient is undergoing therapy. Therefore, to more accurately evaluate the treatment planning system (TPS) capabilities, gamma passing rates were examined for beams of different complexity passing through inhomogeneous phantoms. Materials and methods The research was performed using Siemens Oncor Expression linear accelerator, Siemens Somatom Open CT simulator and Elekta Monaco TPS. A 2D detector array was used to evaluate dose distribution accuracy in homogeneous, semi-anthropomorphic and anthropomorphic phantoms. Validation was based on gamma analysis with 3%/3mm and 2%/2mm criteria, respectively. Results Passing rates of the complex dose distributions degrade depending on the thickness of non-water equivalent material. They also depend on dose reporting mode used. It is observed that the passing rate decreases with plan complexity. Comparison of the data for all set-ups of semi-anthropomorphic and anthropomorphic phantoms shows that passing rates are higher in the anthropomorphic phantom. Conclusions Presented results raise a question of possible limits of dose distribution verification in assessment of plan delivery quality. Consequently, good results obtained using standard patient specific dosimetry methodology do not guarantee the accuracy of delivered dose distribution in real clinical cases.
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Affiliation(s)
| | - David Rajlic
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
| | - Bozidar Casar
- Institute of Oncology LJubljana, Department of Radiation Physics, Ljubljana, Slovenia
| | | | - Nevena Obajdin
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
| | - Dario Faj
- Faculty of Medicine, University of Osijek, Osijek, Croatia
- Faculty of Dental Medicine and Health, University of Osijek, Osijek, Croatia
| | - Slaven Jurkovic
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
- Department of Medical Physics and Biophysics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Reynaert N, Crop F, Sterpin E, Kawrakow I, Palmans H. On the conversion of dose to bone to dose to water in radiotherapy treatment planning systems. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 5:26-30. [PMID: 33458365 PMCID: PMC7807555 DOI: 10.1016/j.phro.2018.01.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/21/2017] [Accepted: 01/17/2018] [Indexed: 11/16/2022]
Abstract
Background and purpose Conversion factors between dose to medium (Dm,m) and dose to water (Dw,w) provided by treatment planning systems that model the patient as water with variable electron density are currently based on stopping power ratios. In the current paper it will be illustrated that this conversion method is not correct. Materials and methods Monte Carlo calculations were performed in a phantom consisting of a 2 cm bone layer surrounded by water. Dw,w was obtained by modelling the bone layer as water with the electron density of bone. Conversion factors between Dw,w and Dm,m were obtained and compared to stopping power ratios and ratios of mass-energy absorption coefficients in regions of electronic equilibrium and interfaces. Calculations were performed for 6 MV and 20 MV photon beams. Results In the region of electronic equilibrium the stopping power ratio of water to bone (1.11) largely overestimates the conversion obtained using the Monte Carlo calculations (1.06). In that region the MC dose conversion corresponds to the ratio of mass energy absorption coefficients. Near the water to bone interface, the MC ratio cannot be determined from stopping powers or mass energy absorption coefficients. Conclusion Stopping power ratios cannot be used for conversion from Dm,m to Dw,w provided by treatment planning systems that model the patient as water with variable electron density, either in regions of electronic equilibrium or near interfaces. In regions of electronic equilibrium mass energy absorption coefficient ratios should be used. Conversions at interfaces require detailed MC calculations.
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Affiliation(s)
- Nick Reynaert
- Institut Jules Bordet, Belgium.,Centre Oscar Lambret, Lille, France
| | | | - Edmond Sterpin
- Katholieke Universiteit Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, Leuven, Belgium.,Université catholique de Louvain, Institut de Recherche expérimentale et Clinique, Center of Molecular Imaging, Radiotherapy and Oncology, Brussels, Belgium
| | - Iwan Kawrakow
- Viewray, 2 Thermo Fisher Way, Oakwood Village, OH 44146, USA
| | - Hugo Palmans
- National Physics Laboratory, Acoustics and Ionising Radiation Division, Teddington, TW 11 0LW, UK.,EBG MedAustron GmbH, Medical Physics Department, Wiener Neustadt A-2700, Austria
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Radojčić ÐS, Kolacio MŠ, Radojčić M, Rajlić D, Casar B, Faj D, Jurković S. Comparison of calculated dose distributions reported as dose-to-water and dose-to-medium for intensity-modulated radiotherapy of nasopharyngeal cancer patients. Med Dosim 2018; 43:363-369. [PMID: 29306538 DOI: 10.1016/j.meddos.2017.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 12/25/2022]
Abstract
Advanced dose calculation algorithms for radiation therapy treatment planning can report external beam photon dose 2-sided, in terms of dose-to-medium (Dm) and dose-to-water (Dw). The purpose of our study was to determinate the effect of Dw and Dm reporting modes built in Elekta Monaco treatment planning system on intensity-modulated radiotherapy dose distributions for patients with nasopharyngeal cancer. For 13 patients involved in this retrospective study, 2 plans were created: 1 using Dw and another according to Dm reporting mode. Treatment plans were normalized such that 100% planning target volume should be covered by 95% of prescribed dose. Dose-volume constraints were assigned according to international standards. The comparison between dose distributions was performed evaluating quantities important for respective volumes of interest. For target volumes, heterogeneity index and conformity index methodology were used along with the maximum dose concept. Also, for the comparisons over particular organ at risk, maximum dose or mean dose as well as dose-volume concepts were used. For all target volumes and majority of organs at risk, the differences between 2 reporting modes are statistically insignificant, but this is not the case for bony structured organs at risks: mandible and cochlea. It was observed that Dw is higher than Dm with mean difference of 9.91% (p = 0.000009) of the mandible volume covered with 70 Gy. The same trend was observed for left and right cochlea with difference in mean dose of 8.74% (p = 0.037) and 6.87% (p = 0.029), respectively. The comparative analysis of dosimetric parameters in this study shows that the selection of reporting modes in Monaco treatment planning system can produce dose differences up to 15% in high-density volumes such as mandible and cochlea, which might have clinical consequences.
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Affiliation(s)
| | | | - Milan Radojčić
- Clinic for Radiotherapy and Oncology, University Hospital Rijeka, Rijeka, Croatia
| | - David Rajlić
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia
| | - Božidar Casar
- Department of Radiation Physics, Institute of Oncology, Ljubljana, Slovenia
| | - Dario Faj
- Faculty of Medicine, University of Osijek, Osijek, Croatia; Faculty of Dental Medicine and Health, University of Osijek, Osijek, Croatia
| | - Slaven Jurković
- Medical Physics Department, University Hospital Rijeka, Rijeka, Croatia; Department of Physics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
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Braad PEN, Andersen T, Hansen SB, Høilund-Carlsen PF. Strategies for CT tissue segmentation for Monte Carlo calculations in nuclear medicine dosimetry. Med Phys 2016; 43:6507. [DOI: 10.1118/1.4967267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Zifodya JM, Challens CHC, Hsieh WL. From AAA to Acuros XB-clinical implications of selecting either Acuros XB dose-to-water or dose-to-medium. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:431-9. [DOI: 10.1007/s13246-016-0436-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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20
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Mundayadan Chandroth M, Venning A, Chick B, Waller B. Effects of contrast materials in IMRT and VMAT of prostate using a commercial Monte Carlo algorithm. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:547-56. [PMID: 26913727 DOI: 10.1007/s13246-016-0427-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 02/05/2016] [Indexed: 12/25/2022]
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21
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Usmani MN, Masai N, Oh RJ, Shiomi H, Tatsumi D, Miura H, Inoue T, Koizumi M. Comparison of Absorbed Dose to Medium and Absorbed Dose to Water for Spine IMRT Plans Using a Commercial Monte Carlo Treatment Planning System. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ijmpcero.2014.31010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Moiseenko V, Liu M, Loewen S, Kosztyla R, Vollans E, Lucido J, Fong M, Vellani R, Popescu IA. Monte Carlo calculation of dose distributions in oligometastatic patients planned for spine stereotactic ablative radiotherapy. Phys Med Biol 2013; 58:7107-16. [DOI: 10.1088/0031-9155/58/20/7107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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23
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Han T, Followill D, Mikell J, Repchak R, Molineu A, Howell R, Salehpour M, Mourtada F. Dosimetric impact of Acuros XB deterministic radiation transport algorithm for heterogeneous dose calculation in lung cancer. Med Phys 2013; 40:051710. [PMID: 23635258 PMCID: PMC3651262 DOI: 10.1118/1.4802216] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/21/2013] [Accepted: 04/05/2013] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The novel deterministic radiation transport algorithm, Acuros XB (AXB), has shown great potential for accurate heterogeneous dose calculation. However, the clinical impact between AXB and other currently used algorithms still needs to be elucidated for translation between these algorithms. The purpose of this study was to investigate the impact of AXB for heterogeneous dose calculation in lung cancer for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). METHODS The thorax phantom from the Radiological Physics Center (RPC) was used for this study. IMRT and VMAT plans were created for the phantom in the Eclipse 11.0 treatment planning system. Each plan was delivered to the phantom three times using a Varian Clinac iX linear accelerator to ensure reproducibility. Thermoluminescent dosimeters (TLDs) and Gafchromic EBT2 film were placed inside the phantom to measure delivered doses. The measurements were compared with dose calculations from AXB 11.0.21 and the anisotropic analytical algorithm (AAA) 11.0.21. Two dose reporting modes of AXB, dose-to-medium in medium (Dm,m) and dose-to-water in medium (Dw,m), were studied. Point doses, dose profiles, and gamma analysis were used to quantify the agreement between measurements and calculations from both AXB and AAA. The computation times for AAA and AXB were also evaluated. RESULTS For the RPC lung phantom, AAA and AXB dose predictions were found in good agreement to TLD and film measurements for both IMRT and VMAT plans. TLD dose predictions were within 0.4%-4.4% to AXB doses (both Dm,m and Dw,m); and within 2.5%-6.4% to AAA doses, respectively. For the film comparisons, the gamma indexes (± 3%∕3 mm criteria) were 94%, 97%, and 98% for AAA, AXB_Dm,m, and AXB_Dw,m, respectively. The differences between AXB and AAA in dose-volume histogram mean doses were within 2% in the planning target volume, lung, heart, and within 5% in the spinal cord. However, differences up to 8% between AXB and AAA were found at lung∕soft tissue interface regions for individual IMRT fields. AAA was found to be 5-6 times faster than AXB for IMRT, while AXB was 4-5 times faster than AAA for VMAT plan. CONCLUSIONS AXB is satisfactorily accurate for the dose calculation in lung cancer for both IMRT and VMAT plans. The differences between AXB and AAA are generally small except in heterogeneous interface regions. AXB Dw,m and Dm,m calculations are similar inside the soft tissue and lung regions. AXB can benefit lung VMAT plans by both improving accuracy and reducing computation time.
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Affiliation(s)
- Tao Han
- Department of Radiation Physics, the University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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Fogliata A, Scorsetti M, Navarria P, Catalano M, Clivio A, Cozzi L, Lobefalo F, Nicolini G, Palumbo V, Pellegrini C, Reggiori G, Roggio A, Vanetti E, Alongi F, Pentimalli S, Mancosu P. Dosimetric comparison between VMAT with different dose calculation algorithms and protons for soft-tissue sarcoma radiotherapy. Acta Oncol 2013; 52:545-52. [PMID: 22671576 DOI: 10.3109/0284186x.2012.689853] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND To appraise the potential of volumetric modulated arc therapy (VMAT, RapidArc) and proton beams to simultaneously achieve target coverage and enhanced sparing of bone tissue in the treatment of soft-tissue sarcoma with adequate target coverage. MATERIAL AND METHODS Ten patients presenting with soft-tissue sarcoma of the leg were collected for the study. Dose was prescribed to 66.5 Gy in 25 fractions to the planning target volume (PTV) while significant maximum dose to the bone was constrained to 50 Gy. Plans were optimised according to the RapidArc technique with 6 MV photon beams or for intensity modulated protons. RapidArc photon plans were computed with: 1) AAA; 2) Acuros XB as dose to medium; and 3) Acuros XB as dose to water. RESULTS All plans acceptably met the criteria of target coverage (V95% >90-95%) and bone sparing (D(1 cm3) <50 Gy). Significantly higher PTV dose homogeneity was found for proton plans. Near-to-maximum dose to bone was similar for RapidArc and protons, while volume receiving medium/low dose levels was minimised with protons. Similar results were obtained for the remaining normal tissue. Dose distributions calculated with the dose to water option resulted ~5% higher than corresponding ones computed as dose to medium. CONCLUSION High plan quality was demonstrated for both VMAT and proton techniques when applied to soft-tissue sarcoma.
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Affiliation(s)
- Antonella Fogliata
- Oncology Institute of Southern Switzerland, Medical Physics Unit,
Bellinzona, Switzerland
| | - Marta Scorsetti
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Piera Navarria
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Maddalena Catalano
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Alessandro Clivio
- Oncology Institute of Southern Switzerland, Medical Physics Unit,
Bellinzona, Switzerland
| | - Luca Cozzi
- Oncology Institute of Southern Switzerland, Medical Physics Unit,
Bellinzona, Switzerland
| | - Francesca Lobefalo
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Giorgia Nicolini
- Oncology Institute of Southern Switzerland, Medical Physics Unit,
Bellinzona, Switzerland
| | - Valentina Palumbo
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Chiara Pellegrini
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Giacomo Reggiori
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Antonella Roggio
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Eugenio Vanetti
- Oncology Institute of Southern Switzerland, Medical Physics Unit,
Bellinzona, Switzerland
| | - Filippo Alongi
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Sara Pentimalli
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
| | - Pietro Mancosu
- IRCCS Istituto Clinico Humanitas, Radiation Oncology,
Rozzano, Milan, Italy
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Tedgren ÅC, Carlsson GA. Specification of absorbed dose to water using model-based dose calculation algorithms for treatment planning in brachytherapy. Phys Med Biol 2013; 58:2561-79. [PMID: 23528349 DOI: 10.1088/0031-9155/58/8/2561] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Model-based dose calculation algorithms (MBDCAs), recently introduced in treatment planning systems (TPS) for brachytherapy, calculate tissue absorbed doses. In the TPS framework, doses have hereto been reported as dose to water and water may still be preferred as a dose specification medium. Dose to tissue medium Dmed then needs to be converted into dose to water in tissue Dw,med. Methods to calculate absorbed dose to differently sized water compartments/cavities inside tissue, infinitesimal (used for definition of absorbed dose), small, large or intermediate, are reviewed. Burlin theory is applied to estimate photon energies at which cavity sizes in the range 1 nm-10 mm can be considered small or large. Photon and electron energy spectra are calculated at 1 cm distance from the central axis in cylindrical phantoms of bone, muscle and adipose tissue for 20, 50, 300 keV photons and photons from (125)I, (169)Yb and (192)Ir sources; ratios of mass-collision-stopping powers and mass energy absorption coefficients are calculated as applicable to convert Dmed into Dw,med for small and large cavities. Results show that 1-10 nm sized cavities are small at all investigated photon energies; 100 µm cavities are large only at photon energies <20 keV. A choice of an appropriate conversion coefficient Dw, med/Dmed is discussed in terms of the cavity size in relation to the size of important cellular targets. Free radicals from DNA bound water of nanometre dimensions contribute to DNA damage and cell killing and may be the most important water compartment in cells implying use of ratios of mass-collision-stopping powers for converting Dmed into Dw,med.
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Affiliation(s)
- Åsa Carlsson Tedgren
- Radiation Physics, Department of Medical and Health Sciences, Linköping University and Center of Medical Image Science and Visualization, SE-581 85 Linköping, Sweden.
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Beaulieu L, Carlsson Tedgren A, Carrier JF, Davis SD, Mourtada F, Rivard MJ, Thomson RM, Verhaegen F, Wareing TA, Williamson JF. Report of the Task Group 186 on model-based dose calculation methods in brachytherapy beyond the TG-43 formalism: Current status and recommendations for clinical implementation. Med Phys 2012; 39:6208-36. [PMID: 23039658 DOI: 10.1118/1.4747264] [Citation(s) in RCA: 345] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Luc Beaulieu
- Département de Radio-Oncologie, Centre hospitalier universitaire de Québec, Québec, Québec G1R 2J6, Canada.
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Enger SA, Ahnesjö A, Verhaegen F, Beaulieu L. Dose to tissue medium or water cavities as surrogate for the dose to cell nuclei at brachytherapy photon energies. Phys Med Biol 2012; 57:4489-500. [DOI: 10.1088/0031-9155/57/14/4489] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Han T, Mourtada F, Kisling K, Mikell J, Followill D, Howell R. Experimental validation of deterministic Acuros XB algorithm for IMRT and VMAT dose calculations with the Radiological Physics Center's head and neck phantom. Med Phys 2012; 39:2193-202. [PMID: 22482641 PMCID: PMC3337663 DOI: 10.1118/1.3692180] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/09/2012] [Accepted: 02/14/2012] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The purpose of this study was to verify the dosimetric performance of Acuros XB (AXB), a grid-based Boltzmann solver, in intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). METHODS The Radiological Physics Center (RPC) head and neck (H&N) phantom was used for all calculations and measurements in this study. Clinically equivalent IMRT and VMAT plans were created on the RPC H&N phantom in the Eclipse treatment planning system (version 10.0) by using RPC dose prescription specifications. The dose distributions were calculated with two different algorithms, AXB 11.0.03 and anisotropic analytical algorithm (AAA) 10.0.24. Two dose report modes of AXB were recorded: dose-to-medium in medium (D(m,m)) and dose-to-water in medium (D(w,m)). Each treatment plan was delivered to the RPC phantom three times for reproducibility by using a Varian Clinac iX linear accelerator. Absolute point dose and planar dose were measured with thermoluminescent dosimeters (TLDs) and GafChromic® EBT2 film, respectively. Profile comparison and 2D gamma analysis were used to quantify the agreement between the film measurements and the calculated dose distributions from both AXB and AAA. The computation times for AAA and AXB were also evaluated. RESULTS Good agreement was observed between measured doses and those calculated with AAA or AXB. Both AAA and AXB calculated doses within 5% of TLD measurements in both the IMRT and VMAT plans. Results of AXB_D(m,m) (0.1% to 3.6%) were slightly better than AAA (0.2% to 4.6%) or AXB_D(w,m) (0.3% to 5.1%). The gamma analysis for both AAA and AXB met the RPC 7%/4 mm criteria (over 90% passed), whereas AXB_D(m,m) met 5%/3 mm criteria in most cases. AAA was 2 to 3 times faster than AXB for IMRT, whereas AXB was 4-6 times faster than AAA for VMAT. CONCLUSIONS AXB was found to be satisfactorily accurate when compared to measurements in the RPC H&N phantom. Compared with AAA, AXB results were equal to or better than those obtained with film measurements for IMRT and VMAT plans. The AXB_D(m,m) reporting mode was found to be closer to TLD and film measurements than was the AXB_D(w,m) mode. AXB calculation time was found to be significantly shorter (× 4) than AAA for VMAT.
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Affiliation(s)
- Tao Han
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Han T, Mikell JK, Salehpour M, Mourtada F. Dosimetric comparison of Acuros XB deterministic radiation transport method with Monte Carlo and model-based convolution methods in heterogeneous media. Med Phys 2011; 38:2651-64. [PMID: 21776802 PMCID: PMC3107831 DOI: 10.1118/1.3582690] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The deterministic Acuros XB (AXB) algorithm was recently implemented in the Eclipse treatment planning system. The goal of this study was to compare AXB performance to Monte Carlo (MC) and two standard clinical convolution methods: the anisotropic analytical algorithm (AAA) and the collapsed-cone convolution (CCC) method. METHODS Homogeneous water and multilayer slab virtual phantoms were used for this study. The multilayer slab phantom had three different materials, representing soft tissue, bone, and lung. Depth dose and lateral dose profiles from AXB v10 in Eclipse were compared to AAA v10 in Eclipse, CCC in Pinnacle3, and EGSnrc MC simulations for 6 and 18 MV photon beams with open fields for both phantoms. In order to further reveal the dosimetric differences between AXB and AAA or CCC, three-dimensional (3D) gamma index analyses were conducted in slab regions and subregions defined by AAPM Task Group 53. RESULTS The AXB calculations were found to be closer to MC than both AAA and CCC for all the investigated plans, especially in bone and lung regions. The average differences of depth dose profiles between MC and AXB, AAA, or CCC was within 1.1, 4.4, and 2.2%, respectively, for all fields and energies. More specifically, those differences in bone region were up to 1.1, 6.4, and 1.6%; in lung region were up to 0.9, 11.6, and 4.5% for AXB, AAA, and CCC, respectively. AXB was also found to have better dose predictions than AAA and CCC at the tissue interfaces where backscatter occurs. 3D gamma index analyses (percent of dose voxels passing a 2%/2 mm criterion) showed that the dose differences between AAA and AXB are significant (under 60% passed) in the bone region for all field sizes of 6 MV and in the lung region for most of field sizes of both energies. The difference between AXB and CCC was generally small (over 90% passed) except in the lung region for 18 MV 10 x 10 cm2 fields (over 26% passed) and in the bone region for 5 x 5 and 10 x 10 cm2 fields (over 64% passed). With the criterion relaxed to 5%/2 mm, the pass rates were over 90% for both AAA and CCC relative to AXB for all energies and fields, with the exception of AAA 18 MV 2.5 x 2.5 cm2 field, which still did not pass. CONCLUSIONS In heterogeneous media, AXB dose prediction ability appears to be comparable to MC and superior to current clinical convolution methods. The dose differences between AXB and AAA or CCC are mainly in the bone, lung, and interface regions. The spatial distributions of these differences depend on the field sizes and energies.
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Affiliation(s)
- Tao Han
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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Landry G, Reniers B, Pignol JP, Beaulieu L, Verhaegen F. The difference of scoring dose to water or tissues in Monte Carlo dose calculations for low energy brachytherapy photon sources. Med Phys 2011; 38:1526-33. [PMID: 21520864 DOI: 10.1118/1.3549760] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The goal of this work is to compare D(m,m) (radiation transported in medium; dose scored in medium) and D(w,m) (radiation transported in medium; dose scored in water) obtained from Monte Carlo (MC) simulations for a subset of human tissues of interest in low energy photon brachytherapy. Using low dose rate seeds and an electronic brachytherapy source (EBS), the authors quantify the large cavity theory conversion factors required. The authors also assess whether ap plying large cavity theory utilizing the sources' initial photon spectra and average photon energy induces errors related to spatial spectral variations. First, ideal spherical geometries were investigated, followed by clinical brachytherapy LDR seed implants for breast and prostate cancer patients. METHODS Two types of dose calculations are performed with the GEANT4 MC code. (1) For several human tissues, dose profiles are obtained in spherical geometries centered on four types of low energy brachytherapy sources: 125I, 103Pd, and 131Cs seeds, as well as an EBS operating at 50 kV. Ratios of D(w,m) over D(m,m) are evaluated in the 0-6 cm range. In addition to mean tissue composition, compositions corresponding to one standard deviation from the mean are also studied. (2) Four clinical breast (using 103Pd) and prostate (using 125I) brachytherapy seed implants are considered. MC dose calculations are performed based on postimplant CT scans using prostate and breast tissue compositions. PTV D90 values are compared for D(w,m) and D(m,m). RESULTS (1) Differences (D(w,m)/D(m,m)-1) of -3% to 70% are observed for the investigated tissues. For a given tissue, D(w,m)/D(m,m) is similar for all sources within 4% and does not vary more than 2% with distance due to very moderate spectral shifts. Variations of tissue composition about the assumed mean composition influence the conversion factors up to 38%. (2) The ratio of D90(w,m) over D90(m,m) for clinical implants matches D(w,m)/D(m,m) at 1 cm from the single point sources, CONCLUSIONS Given the small variation with distance, using conversion factors based on the emitted photon spectrum (or its mean energy) of a given source introduces minimal error. The large differences observed between scoring schemes underline the need for guidelines on choice of media for dose reporting. Providing such guidelines is beyond the scope of this work.
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Affiliation(s)
- Guillaume Landry
- Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN, The Netherlands
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Ma CM, Li J. Dose specification for radiation therapy: dose to water or dose to medium? Phys Med Biol 2011; 56:3073-89. [DOI: 10.1088/0031-9155/56/10/012] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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