1
|
Kishi N, Matsuo Y, Yoneyama M, Ueki K, Mizowaki T. Symptomatic radiation pneumonitis after stereotactic body radiotherapy for multiple pulmonary oligometastases or synchronous primary lung cancer. Adv Radiat Oncol 2022; 7:100911. [PMID: 35647407 PMCID: PMC9133396 DOI: 10.1016/j.adro.2022.100911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/18/2022] [Indexed: 11/28/2022] Open
|
2
|
Fogliata A, Cozzi L. Dose calculation algorithm accuracy for small fields in non-homogeneous media: The lung SBRT case. Phys Med 2017; 44:157-162. [DOI: 10.1016/j.ejmp.2016.11.104] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/02/2016] [Accepted: 11/10/2016] [Indexed: 11/28/2022] Open
|
3
|
Zhao Y, Qi G, Yin G, Wang X, Wang P, Li J, Xiao M, Li J, Kang S, Liao X. A clinical study of lung cancer dose calculation accuracy with Monte Carlo simulation. Radiat Oncol 2014; 9:287. [PMID: 25511623 PMCID: PMC4276018 DOI: 10.1186/s13014-014-0287-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 12/04/2014] [Indexed: 11/23/2022] Open
Abstract
Background The accuracy of dose calculation is crucial to the quality of treatment planning and, consequently, to the dose delivered to patients undergoing radiation therapy. Current general calculation algorithms such as Pencil Beam Convolution (PBC) and Collapsed Cone Convolution (CCC) have shortcomings in regard to severe inhomogeneities, particularly in those regions where charged particle equilibrium does not hold. The aim of this study was to evaluate the accuracy of the PBC and CCC algorithms in lung cancer radiotherapy using Monte Carlo (MC) technology. Methods and materials Four treatment plans were designed using Oncentra Masterplan TPS for each patient. Two intensity-modulated radiation therapy (IMRT) plans were developed using the PBC and CCC algorithms, and two three-dimensional conformal therapy (3DCRT) plans were developed using the PBC and CCC algorithms. The DICOM-RT files of the treatment plans were exported to the Monte Carlo system to recalculate. The dose distributions of GTV, PTV and ipsilateral lung calculated by the TPS and MC were compared. Result For 3DCRT and IMRT plans, the mean dose differences for GTV between the CCC and MC increased with decreasing of the GTV volume. For IMRT, the mean dose differences were found to be higher than that of 3DCRT. The CCC algorithm overestimated the GTV mean dose by approximately 3% for IMRT. For 3DCRT plans, when the volume of the GTV was greater than 100 cm3, the mean doses calculated by CCC and MC almost have no difference. PBC shows large deviations from the MC algorithm. For the dose to the ipsilateral lung, the CCC algorithm overestimated the dose to the entire lung, and the PBC algorithm overestimated V20 but underestimated V5; the difference in V10 was not statistically significant. Conclusions PBC substantially overestimates the dose to the tumour, but the CCC is similar to the MC simulation. It is recommended that the treatment plans for lung cancer be developed using an advanced dose calculation algorithm other than PBC. MC can accurately calculate the dose distribution in lung cancer and can provide a notably effective tool for benchmarking the performance of other dose calculation algorithms within patients.
Collapse
Affiliation(s)
- Yanqun Zhao
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Guohai Qi
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Gang Yin
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Xianliang Wang
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Pei Wang
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Jian Li
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Mingyong Xiao
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Jie Li
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Shengwei Kang
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| | - Xiongfei Liao
- Department of Radiation Oncology, Sichuan Provincial Cancer Hospital, Chengdu, Sichuan, 610041, China.
| |
Collapse
|
4
|
Lohr F, Georg D, Cozzi L, Eich HT, Weber DC, Koeck J, Knäusl B, Dieckmann K, Abo-Madyan Y, Fiandra C, Mueller RP, Engert A, Ricardi U. Novel radiotherapy techniques for involved-field and involved-node treatment of mediastinal Hodgkin lymphoma: when should they be considered and which questions remain open? Strahlenther Onkol 2014; 190:864-6, 868-71. [PMID: 25209551 DOI: 10.1007/s00066-014-0719-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/01/2014] [Indexed: 01/10/2023]
Abstract
PURPOSE Hodgkin lymphoma (HL) is a highly curable disease. Reducing late complications and second malignancies has become increasingly important. Radiotherapy target paradigms are currently changing and radiotherapy techniques are evolving rapidly. DESIGN This overview reports to what extent target volume reduction in involved-node (IN) and advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy-compared with involved-field (IF) and 3D radiotherapy (3D-RT)- can reduce high doses to organs at risk (OAR) and examines the issues that still remain open. RESULTS Although no comparison of all available techniques on identical patient datasets exists, clear patterns emerge. Advanced dose-calculation algorithms (e.g., convolution-superposition/Monte Carlo) should be used in mediastinal HL. INRT consistently reduces treated volumes when compared with IFRT with the exact amount depending on the INRT definition. The number of patients that might significantly benefit from highly conformal techniques such as IMRT over 3D-RT regarding high-dose exposure to organs at risk (OAR) is smaller with INRT. The impact of larger volumes treated with low doses in advanced techniques is unclear. The type of IMRT used (static/rotational) is of minor importance. All advanced photon techniques result in similar potential benefits and disadvantages, therefore only the degree-of-modulation should be chosen based on individual treatment goals. Treatment in deep inspiration breath hold is being evaluated. Protons theoretically provide both excellent high-dose conformality and reduced integral dose. CONCLUSION Further reduction of treated volumes most effectively reduces OAR dose, most likely without disadvantages if the excellent control rates achieved currently are maintained. For both IFRT and INRT, the benefits of advanced radiotherapy techniques depend on the individual patient/target geometry. Their use should therefore be decided case by case with comparative treatment planning.
Collapse
Affiliation(s)
- Frank Lohr
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany,
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Stereotactic body radiotherapy for small lung tumors in the University of Tokyo Hospital. BIOMED RESEARCH INTERNATIONAL 2014; 2014:136513. [PMID: 25110653 PMCID: PMC4109604 DOI: 10.1155/2014/136513] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/03/2014] [Accepted: 06/18/2014] [Indexed: 01/08/2023]
Abstract
Our work on stereotactic body radiation therapy (SBRT) for primary and metastatic lung tumors will be described. The eligibility criteria for SBRT, our previous SBRT method, the definition of target volume, heterogeneity correction, the position adjustment using four-dimensional cone-beam computed tomography (4D CBCT) immediately before SBRT, volumetric modulated arc therapy (VMAT) method for SBRT, verifying of tumor position within internal target volume (ITV) using in-treatment 4D-CBCT during VMAT-SBRT, shortening of treatment time using flattening-filter-free (FFF) techniques, delivery of 4D dose calculation for lung-VMAT patients using in-treatment CBCT and LINAC log data with agility multileaf collimator, and SBRT method for centrally located lung tumors in our institution will be shown. In our institution, these efforts have been made with the goal of raising the local control rate and decreasing adverse effects after SBRT.
Collapse
|
6
|
Benhalouche S, Visvikis D, Le Maitre A, Pradier O, Boussion N. Evaluation of clinical IMRT treatment planning using the GATE Monte Carlo simulation platform for absolute and relative dose calculations. Med Phys 2013; 40:021711. [DOI: 10.1118/1.4774358] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
|
7
|
Koeck J, Abo-Madyan Y, Eich HT, Stieler F, Fleckenstein J, Kriz J, Mueller RP, Wenz F, Lohr F. Clinical relevance of different dose calculation strategies for mediastinal IMRT in Hodgkin's disease. Strahlenther Onkol 2012; 188:653-9. [PMID: 22740169 DOI: 10.1007/s00066-012-0144-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND PURPOSE Conventional algorithms show uncertainties in dose calculation already for three-dimensional conformal radiotherapy (3D-CRT). Intensity-modulated radiotherapy (IMRT) might even increase these. We wanted to assess differences in dose distribution for pencil beam (PB), collapsed cone (CC), and Monte Carlo (MC) algorithm for both 3D-CRT and IMRT in patients with mediastinal Hodgkin lymphoma. PATIENTS AND METHODS Based on 20 computed tomograph (CT) datasets of patients with mediastinal Hodgkin lymphoma, we created treatment plans according to the guidelines of the German Hodgkin Study Group (GHSG) with PB and CC algorithm for 3D-CRT and with PB and MC algorithm for IMRT. Doses were compared for planning target volume (PTV) and organs at risk. RESULTS For 3D-CRT, PB overestimated PTV(95) and V(20) of the lung by 6.9% and 3.3% and underestimated V(10) of the lung by 5.8%, compared to the CC algorithm. For IMRT, PB overestimated PTV(95), V(20) of the lung, V(25) of the heart and V(10) of the female left/right breast by 8.1%, 25.8%, 14.0% and 43.6%/189.1%, and underestimated V(10) of the lung, V(4) of the heart and V(4) of the female left/right breast by 6.3%, 6.8% and 23.2%/15.6%, compared to MC. CONCLUSION The PB algorithm underestimates low doses to the organs at risk and overestimates dose to PTV and high doses to the organs at risk. For 3D-CRT, a well-modeled PB algorithm is clinically acceptable; for IMRT planning, however, an advanced algorithm such as CC or MC should be used at least for part of the plan optimization.
Collapse
Affiliation(s)
- J Koeck
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68135, Mannheim, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Radiotherapy for Early Mediastinal Hodgkin Lymphoma According to the German Hodgkin Study Group (GHSG): The Roles of Intensity-Modulated Radiotherapy and Involved-Node Radiotherapy. Int J Radiat Oncol Biol Phys 2012; 83:268-76. [DOI: 10.1016/j.ijrobp.2011.05.054] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 05/27/2011] [Indexed: 11/20/2022]
|
9
|
Takahashi W, Yamashita H, Saotome N, Iwai Y, Sakumi A, Haga A, Nakagawa K. Evaluation of heterogeneity dose distributions for Stereotactic Radiotherapy (SRT): comparison of commercially available Monte Carlo dose calculation with other algorithms. Radiat Oncol 2012; 7:20. [PMID: 22315950 PMCID: PMC3305645 DOI: 10.1186/1748-717x-7-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 02/09/2012] [Indexed: 12/02/2022] Open
Abstract
Background The purpose of this study was to compare dose distributions from three different algorithms with the x-ray Voxel Monte Carlo (XVMC) calculations, in actual computed tomography (CT) scans for use in stereotactic radiotherapy (SRT) of small lung cancers. Methods Slow CT scan of 20 patients was performed and the internal target volume (ITV) was delineated on Pinnacle3. All plans were first calculated with a scatter homogeneous mode (SHM) which is compatible with Clarkson algorithm using Pinnacle3 treatment planning system (TPS). The planned dose was 48 Gy in 4 fractions. In a second step, the CT images, structures and beam data were exported to other treatment planning systems (TPSs). Collapsed cone convolution (CCC) from Pinnacle3, superposition (SP) from XiO, and XVMC from Monaco were used for recalculating. The dose distributions and the Dose Volume Histograms (DVHs) were compared with each other. Results The phantom test revealed that all algorithms could reproduce the measured data within 1% except for the SHM with inhomogeneous phantom. For the patient study, the SHM greatly overestimated the isocenter (IC) doses and the minimal dose received by 95% of the PTV (PTV95) compared to XVMC. The differences in mean doses were 2.96 Gy (6.17%) for IC and 5.02 Gy (11.18%) for PTV95. The DVH's and dose distributions with CCC and SP were in agreement with those obtained by XVMC. The average differences in IC doses between CCC and XVMC, and SP and XVMC were -1.14% (p = 0.17), and -2.67% (p = 0.0036), respectively. Conclusions Our work clearly confirms that the actual practice of relying solely on a Clarkson algorithm may be inappropriate for SRT planning. Meanwhile, CCC and SP were close to XVMC simulations and actual dose distributions obtained in lung SRT.
Collapse
Affiliation(s)
- Wataru Takahashi
- Department of Radiology, University of Tokyo Hospital, Hongo, Bunkyo-ku, Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
10
|
Uhl M, Sterzing F, Habl G, Schubert K, Sroka-Perez G, Debus J, Herfarth K. CT-Myelography for High-Dose Irradiation of Spinal and Paraspinal Tumors with Helical Tomotherapy. Strahlenther Onkol 2011; 187:416-20. [DOI: 10.1007/s00066-011-2219-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
|
11
|
Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans. Int J Radiat Oncol Biol Phys 2010; 78:955-63. [DOI: 10.1016/j.ijrobp.2009.08.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 05/31/2009] [Accepted: 08/15/2009] [Indexed: 12/14/2022]
|
12
|
The effect of planning algorithms in oesophageal radiotherapy in the context of the SCOPE 1 trial. Radiother Oncol 2009; 93:462-7. [DOI: 10.1016/j.radonc.2009.08.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 08/21/2009] [Accepted: 08/24/2009] [Indexed: 11/21/2022]
|
13
|
Aarup LR, Nahum AE, Zacharatou C, Juhler-Nøttrup T, Knöös T, Nyström H, Specht L, Wieslander E, Korreman SS. The effect of different lung densities on the accuracy of various radiotherapy dose calculation methods: Implications for tumour coverage. Radiother Oncol 2009; 91:405-14. [PMID: 19297051 DOI: 10.1016/j.radonc.2009.01.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 01/22/2009] [Accepted: 01/24/2009] [Indexed: 11/27/2022]
|
14
|
Morgan AM, Knöös T, McNee SG, Evans CJ, Thwaites DI. Clinical implications of the implementation of advanced treatment planning algorithms for thoracic treatments. Radiother Oncol 2008; 86:48-54. [PMID: 18155309 DOI: 10.1016/j.radonc.2007.11.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/28/2007] [Accepted: 11/28/2007] [Indexed: 11/15/2022]
Affiliation(s)
- Andrew M Morgan
- Medical Physics and Engineering, Leeds Teaching Hospitals, University of Leeds, UK
| | | | | | | | | |
Collapse
|
15
|
Ernst-Stecken A, Lambrecht U, Mueller R, Sauer R, Grabenbauer G. Hypofractionated stereotactic radiotherapy for primary and secondary intrapulmonary tumors: first results of a phase I/II study. Strahlenther Onkol 2007; 182:696-702. [PMID: 17149575 PMCID: PMC3233368 DOI: 10.1007/s00066-006-1577-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 08/18/2006] [Indexed: 01/19/2023]
Abstract
PURPOSE To evaluate the feasibility, efficacy, and side effects of dose escalation in hypofractionated stereotactic radiotherapy (hfSRT) for intrapulmonary tumors with the Novalis system (BrainLAB AG, Heimstetten, Germany). PATIENTS AND METHODS From 07/2003 to 01/2005, 21 patients/39 tumors were treated with 5 x 7 Gy (n = 21; total dose 35 Gy) or 5 x 8 Gy (n = 18; total dose 40 Gy). There were three cases of primary lung cancer, the remainder were metastases. Median gross tumor volume (GTV) and planning target volume (PTV) were 2.89 cm(3) (range, 0.15-67.94 cm(3)) and 25.75 cm(3) (range, 7.18-124.04 cm(3)), respectively. RESULTS Rates of complete remission, partial remission, no change, and progressive disease were 51%, 33%, 3%, and 13%, respectively. No grade 4 toxicity occurred, nearly all patients had grade 1 initially. One grade 3 toxicity, i.e., dyspnea, was documented for a period of 6 months after therapy. Radiosurgery quality assurance guidelines could be met. CONCLUSION hfSRT of primary and secondary lung tumors using a schedule of five fractions at 7-8 Gy each was well tolerated. Further dose escalation is planned.
Collapse
Affiliation(s)
- Antje Ernst-Stecken
- Department of Radiation Therapy and Novalis Shaped Beam Surgery Center, University Hospital Erlangen, Erlangen, Germany.
| | | | | | | | | |
Collapse
|
16
|
Kyas I, Hof H, Debus J, Schlegel W, Karger CP. Prediction of radiation-induced changes in the lung after stereotactic body radiation therapy of non–small-cell lung cancer. Int J Radiat Oncol Biol Phys 2007; 67:768-74. [PMID: 17097829 DOI: 10.1016/j.ijrobp.2006.08.066] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 08/24/2006] [Accepted: 08/25/2006] [Indexed: 11/16/2022]
Abstract
PURPOSE To estimate the risk of radiation-induced changes in the lung before single-dose treatment (stereotactic body radiation therapy [SBRT]) of lung cancer, the quantitative dose-response and volume-response relations must be known. METHODS AND MATERIALS A total of 64 patients treated for non-small-cell lung cancer with single doses of 20-30 Gy were classified according to the occurrence or nonoccurrence of perifocal changes in the lung detected by CT. Patients without toxic events in the lung were required to have >or=6 months of follow-up. The mean dose (D(mean)) in the ipsilateral lung and the volume receiving >7 or 10 Gy (V7 and V10, respectively) were used to calculate the dose-response and volume-response curves. The predictive value of additional variables was also investigated. RESULTS Of the 64 patients, 83% exhibited the selected endpoint. The tolerance values at a 50% probability of toxic events were 1.2 +/- 0.7 Gy for the D(mean) and 5.8 +/- 3.0% and 3.1 +/- 2.0% for V7 and V10, respectively. A nonsignificant shift to higher doses was seen for the dose-response curve for the upper compared with the lower part of the lung. CONCLUSION The D(mean), V7, and V10 can be used to predict the risk of lung toxicity after SBRT treatment of non-small-cell lung cancer. Because of the lack of patients with low prescribed doses, however, the related uncertainty of this prediction is still relatively large. The D(mean), V7, and V10 are equally well suited. The additional investigated variables did not provide significant advantages. The lower part of the lung appears to be more radiosensitive than the upper.
Collapse
Affiliation(s)
- Ina Kyas
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | | | | | | | | |
Collapse
|
17
|
Dobler B, Walter C, Knopf A, Fabri D, Loeschel R, Polednik M, Schneider F, Wenz F, Lohr F. Optimization of extracranial stereotactic radiation therapy of small lung lesions using accurate dose calculation algorithms. Radiat Oncol 2006; 1:45. [PMID: 17132177 PMCID: PMC1769387 DOI: 10.1186/1748-717x-1-45] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 11/29/2006] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The aim of this study was to compare and to validate different dose calculation algorithms for the use in radiation therapy of small lung lesions and to optimize the treatment planning using accurate dose calculation algorithms. METHODS A 9-field conformal treatment plan was generated on an inhomogeneous phantom with lung mimics and a soft tissue equivalent insert, mimicking a lung tumor. The dose distribution was calculated with the Pencil Beam and Collapsed Cone algorithms implemented in Masterplan (Nucletron) and the Monte Carlo system XVMC and validated using Gafchromic EBT films. Differences in dose distribution were evaluated. The plans were then optimized by adding segments to the outer shell of the target in order to increase the dose near the interface to the lung. RESULTS The Pencil Beam algorithm overestimated the dose by up to 15% compared to the measurements. Collapsed Cone and Monte Carlo predicted the dose more accurately with a maximum difference of -8% and -3% respectively compared to the film. Plan optimization by adding small segments to the peripheral parts of the target, creating a 2-step fluence modulation, allowed to increase target coverage and homogeneity as compared to the uncorrected 9 field plan. CONCLUSION The use of forward 2-step fluence modulation in radiotherapy of small lung lesions allows the improvement of tumor coverage and dose homogeneity as compared to non-modulated treatment plans and may thus help to increase the local tumor control probability. While the Collapsed Cone algorithm is closer to measurements than the Pencil Beam algorithm, both algorithms are limited at tissue/lung interfaces, leaving Monte-Carlo the most accurate algorithm for dose prediction.
Collapse
Affiliation(s)
- Barbara Dobler
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
- Department of Radiotherapy, Regensburg University Medical Center, Regensburg, Germany
| | - Cornelia Walter
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Antje Knopf
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Daniella Fabri
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Rainer Loeschel
- Department of Computer Science and Mathematics, University of Applied Sciences, Regensburg, Germany
| | - Martin Polednik
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Frank Schneider
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Frank Lohr
- Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| |
Collapse
|
18
|
Bragg CM, Conway J. Dosimetric verification of the anisotropic analytical algorithm for radiotherapy treatment planning. Radiother Oncol 2006; 81:315-23. [PMID: 17125862 DOI: 10.1016/j.radonc.2006.10.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 10/10/2006] [Accepted: 10/27/2006] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE To investigate the accuracy of photon dose calculations performed by the Anisotropic Analytical Algorithm, in homogeneous and inhomogeneous media and in simulated treatment plans. MATERIALS AND METHODS Predicted dose distributions were compared with ionisation chamber and film measurements for a series of increasingly complex situations. Initially, simple and complex fields in a homogeneous medium were studied. The effect of inhomogeneities was investigated using a range of phantoms constructed of water, bone and lung substitute materials. Simulated treatment plans were then produced using a semi-anthropomorphic phantom and the delivered doses compared to the doses predicted by the Anisotropic Analytical Algorithm. RESULTS In a homogeneous medium, agreement was found to be within 2% dose or 2mm dta in most instances. In the presence of heterogeneities, agreement was generally to within 2.5%. The simulated treatment plan measurements agreed to within 2.5% or 2mm. CONCLUSIONS The accuracy of the algorithm was found to be satisfactory at 6 and 10MV both in homogeneous and inhomogeneous situations and in the simulated treatment plans. The algorithm was more accurate than the Pencil Beam Convolution model, particularly in the presence of low density heterogeneities.
Collapse
Affiliation(s)
- Christopher M Bragg
- Department of Radiotherapy Physics, Weston Park Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK.
| | | |
Collapse
|
19
|
Ahnesjö A, Weber L, Murman A, Saxner M, Thorslund I, Traneus E. Beam modeling and verification of a photon beam multisource model. Med Phys 2005; 32:1722-37. [PMID: 16013730 DOI: 10.1118/1.1898485] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Dose calculations for treatment planning of photon beam radiotherapy require a model of the beam to drive the dose calculation models. The beam shaping process involves scattering and filtering that yield radiation components which vary with collimator settings. The necessity to model these components has motivated the development of multisource beam models. We describe and evaluate clinical photon beam modeling based on multisource models, including lateral beam quality variations. The evaluation is based on user data for a pencil kernel algorithm and a point kernel algorithm (collapsed cone) used in the clinical treatment planning systems Helax-TMS and Nucletron-Oncentra. The pencil kernel implementations treat the beam spectrum as lateral invariant while the collapsed cone involves off axis softening of the spectrum. Both algorithms include modeling of head scatter components. The parameters of the beam model are derived from measured beam data in a semiautomatic process called RDH (radiation data handling) that, in sequential steps, minimizes the deviations in calculated dose versus the measured data. The RDH procedure is reviewed and the results of processing data from a large number of treatment units are analyzed for the two dose calculation algorithms. The results for both algorithms are similar, with slightly better results for the collapsed cone implementations. For open beams, 87% of the machines have maximum errors less than 2.5%. For wedged beams the errors were found to increase with increasing wedge angle. Internal, motorized wedges did yield slightly larger errors than external wedges. These results reflect the increased complexity, both experimentally and computationally, when wedges are used compared to open beams.
Collapse
MESH Headings
- Algorithms
- Calibration
- Computer Simulation
- Film Dosimetry
- Models, Statistical
- Models, Theoretical
- Particle Accelerators
- Phantoms, Imaging
- Photons
- Radiometry
- Radiotherapy Dosage
- Radiotherapy Planning, Computer-Assisted/instrumentation
- Radiotherapy Planning, Computer-Assisted/methods
- Radiotherapy, Computer-Assisted/methods
- Radiotherapy, Conformal/instrumentation
- Radiotherapy, Conformal/methods
- Radiotherapy, High-Energy/instrumentation
- Radiotherapy, High-Energy/methods
- Scattering, Radiation
Collapse
Affiliation(s)
- Anders Ahnesjö
- Nucletron Scandinavia AB, Box 1704, 751 47 Uppsala, Sweden.
| | | | | | | | | | | |
Collapse
|