1
|
Ito T, Monzen H, Kubo K, Kosaka H, Yanagi Y, Sakai Y, Inada M, Doi H, Nishimura Y. Dose difference between anisotropic analytical algorithm (AAA) and Acuros XB (AXB) caused by target's air content for volumetric modulated arc therapy of head and neck cancer. Rep Pract Oncol Radiother 2023; 28:399-406. [PMID: 37795404 PMCID: PMC10547402 DOI: 10.5603/rpor.a2023.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/23/2022] [Indexed: 10/06/2023] Open
Abstract
Background We clarified the dose difference between the anisotropic analytical algorithm (AAA) and Acuros XB (AXB) with increasing target's air content using a virtual phantom and clinical cases. Materials and methods Whole neck volumetric modulated arc therapy (VMAT) plan was transferred into a virtual phantom with a cylindrical air structure at the center. The diameter of the air structure was changed from 0 to 6 cm, and the target's air content defined as the air/planning target volume (PTV) in percent (air/PTV) was varied. VMAT plans were recalculated by AAA and AXB with the same monitor unit (MU) and multi-leaf collimator (MLC) motions. The dose at each air/PTV (5%-30%) was compared between each algorithm with D98%, D95%, D50% and D2% for the PTV. In addition, MUs were also compared with the same MLC motions between the D95% prescription with AAA (AAA_D95%), AXB_D95%, and the prescription to 100% minus air/PTV (AXB_D100%-air/PTV) in clinical cases of head and neck (HNC). Results When air/PTV increased (5-30%), the dose differences between AAA and AXB for D98%, D95%, D50% and D2% were 3.08-15.72%, 2.35-13.92%, 0.63-4.59%, and 0.14-6.44%, respectively. At clinical cases with air/PTV of 5.61% and 28.19%, compared to AAA_D95%, the MUs differences were, respectively, 2.03% and 6.74% for AXB_D95% and 1.80% and 0.50% for AXB_D100%-air/PTV. Conclusion The dose difference between AAA and AXB increased as the target's air content increased, and AXB_D95% resulted in a dose escalation over AAA_D95% when the target's air content was ≥ 5%. The D100%-air/PTV of PTV using AXB was comparable to the D95% of PTV using AAA.
Collapse
Affiliation(s)
- Takaaki Ito
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
- Department of Radiological Technology, Kobe City Nishi-Kobe Medical Center, Kobe, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masahiro Inada
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| |
Collapse
|
2
|
The determination of virtual source position using convergent anti-trigonometric functions (arcCOS and arcSIN) method for scanning-passive scatter beam in carbon ion therapy. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2023. [DOI: 10.2478/pjmpe-2023-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Abstract
Introduction: We developed a convergent trigonometric functions technique (arcCOS, arcSIN) capable of dealing with the virtual source position delivered by different carbon ion energies from the pattern of scanning-passive scatter beam in this study.
Materials and Methods: A home-made large-format CMOS sensor and Gaf Chromic EBT3 films were used for the virtual source position measurement. The Gaf films were embedded in a self-designed rectangular plastic frame to tighten the films and set up on a treatment couch for irradiation in the air with the film perpendicular to the carbon ion beam at the nominal source-axis-distance (SAD) as well as upstream and downstream from the SAD. The horizontal carbon ion beam with 5 energies at a machine opening field size was carried out in this study. The virtual source position was determined with a convergent arcCOS and arcSIN methods and compared with the linear regression by back-projecting the FWHM to zero at a distance upstream from the various source-film-distance.
Results: The film FWHM measurement error of 0.5 mm (the large-format CMOS detectors was in pixel, a pixel equals 0.5 mm) leads to 1×10-3% deviation of α(cACOS and cASIN) at every assumed virtual source position. The overall uncertainty for the reproducibility of the calculated virtual source position by the assumed t in the vertical and horizontal directions amounts to 0.1%. The errors of calculated virtual source position by assumed t with back projecting FWHM to zero methods were within 1.1 ± 0.001, p = 0.033. The distance of virtual source positions is decreased from SAD with high to low energy.
Conclusion: We have developed a technique capable of dealing with the virtual source position with a convergent arcCOS and arcSIN methods to avoid any manual measurement mistakes in scanning-passive scatter carbon ion beam. The method for investigating the virtual source position in the carbon ion beam in this study can also be used for external electrons and the proton.
Collapse
|
3
|
Small field output factor measurement and verification for CyberKnife robotic radiotherapy and radiosurgery system using 3D polymer gel, ionization chamber, diode, diamond and scintillator detectors, Gafchromic film and Monte Carlo simulation. Appl Radiat Isot 2023; 192:110576. [PMID: 36473319 DOI: 10.1016/j.apradiso.2022.110576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022]
Abstract
The dosimetry of small fields has become tremendously important with the advent of intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery, where small field segments or very small fields are used to treat tumors. With high dose gradients in the stereotactic radiosurgery or radiotherapy treatment, small field dosimetry becomes challenging due to the lack of lateral electronic equilibrium in the field, x-ray source occlusion, and detector volume averaging. Small volume and tissue-equivalent detectors are recommended to overcome the challenges. With the lack of a perfect radiation detector, studies on available detectors are ongoing with reasonable disagreement and uncertainties. The joint IAEA and AAPM international code of practice (CoP) for small field dosimetry, TRS 483 (Alfonso et al., 2017) provides guidelines and recommendations for the dosimetry of small static fields in external beam radiotherapy. The CoP provides a methodology for field output factor (FOF) measurements and use of field output correction factors for a series of small field detectors and strongly recommends additional measurements, data collection and verification for CyberKnife (CK) robotic stereotactic radiotherapy/radiosurgery system using the listed detectors and more new detectors so that the FOFs can be implemented clinically. The present investigation is focused on using 3D gel along with some other commercially available detectors for the measurement and verification of field output factors (FOFs) for the small fields available in the CK system. The FOF verification was performed through a comparison with published data and Monte Carlo simulation. The results of this study have proved the suitability of an in-house developed 3D polymer gel dosimeter, several commercially available detectors, and Gafchromic films as a part of small field dosimetric measurements for the CK system.
Collapse
|
4
|
Monte-Carlo techniques for radiotherapy applications II: equipment and source modelling, dose calculations and radiobiology. JOURNAL OF RADIOTHERAPY IN PRACTICE 2023. [DOI: 10.1017/s1460396923000080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Abstract
Introduction:
This is the second of two papers giving an overview of the use of Monte-Carlo techniques for radiotherapy applications.
Methods:
The first paper gave an introduction and introduced some of the codes that are available to the user wishing to model the different aspects of radiotherapy treatment. It also aims to serve as a useful companion to a curated collection of papers on Monte-Carlo that have been published in this journal.
Results and Conclusions:
This paper focuses on the application of Monte-Carlo to specific problems in radiotherapy. These include radiotherapy and imaging beam production, brachytherapy, phantom and patient dosimetry, detector modelling and track structure calculations for micro-dosimetry, nano-dosimetry and radiobiology.
Collapse
|
5
|
Li Y, Sun X, Liang Y, Hu Y, Liu C. Monte Carlo simulation of linac using PRIMO. Radiat Oncol 2022; 17:185. [PMID: 36384637 PMCID: PMC9667592 DOI: 10.1186/s13014-022-02149-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022] Open
Abstract
Background Monte Carlo simulation is considered as the most accurate method for dose calculation in radiotherapy. PRIMO is a Monte-Carlo program with a user-friendly graphical interface. Material and method A VitalBeam with 6MV and 6MV flattening filter free (FFF), equipped with the 120 Millennium multileaf collimator was simulated by PRIMO. We adjusted initial energy, energy full width at half maximum (FWHM), focal spot FWHM, and beam divergence to match the measurements. The water tank and ion-chamber were used in the measurement. Percentage depth dose (PDD) and off axis ratio (OAR) were evaluated with gamma passing rates (GPRs) implemented in PRIMO. PDDs were matched at different widths of standard square fields. OARs were matched at five depths. Transmission factor and dose leaf gap (DLG) were simulated. DLG was measured by electronic portal imaging device using a sweeping gap method. Result For the criterion of 2%/2 mm, 1%/2 mm and 1%/1 mm, the GPRs of 6MV PDD were 99.33–100%, 99–100%, and 99–100%, respectively; the GPRs of 6MV FFF PDD were 99.33–100%, 98.99–99.66%, and 97.64–98.99%, respectively; the GPRs of 6MV OAR were 96.4–100%, 90.99–100%, and 85.12–98.62%, respectively; the GPRs of 6MV FFF OAR were 95.15–100%, 89.32–100%, and 87.02–99.74%, respectively. The calculated DLG matched well with the measurement (6MV: 1.36 mm vs. 1.41 mm; 6MV FFF: 1.07 mm vs. 1.03 mm, simulation vs measurement). The transmission factors were similar (6MV: 1.25% vs. 1.32%; 6MV FFF: 0.8% vs. 1.12%, simulation vs measurement). Conclusion The calculated PDD, OAR, DLG and transmission factor were all in good agreement with measurements. PRIMO is an independent (with respect to analytical dose calculation algorithm) and accurate Monte Carlo tool. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-022-02149-5.
Collapse
|
6
|
Duchaine J, Wahl M, Markel D, Bouchard H. A probabilistic approach for determining Monte Carlo beam source parameters: II. Impact of beam modeling uncertainties on dosimetric functions and treatment plans. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4efb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/26/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. The Monte Carlo method is recognized as a valid approach for the evaluation of dosimetric functions for clinical use. This procedure requires the accurate modeling of the considered linear accelerator. In Part I, we propose a new method to extract the probability density function of the beam model physical parameters. The aim of this work is to evaluate the impact of beam modeling uncertainties on Monte Carlo evaluated dosimetric functions and treatment plans in the context of small fields. Approach. Simulations of output factors, output correction factors, dose profiles, percent-depth doses and treatment plans are performed using the CyberKnife M6 model developed in Part I. The optimized pair of electron beam energy and spot size, and eight additional pairs of beam parameters representing a 95% confidence region are used to propagate the uncertainties associated to the source parameters to the dosimetric functions. Main results. For output factors, the impact of beam modeling uncertainties increases with the reduction of the field size and confidence interval half widths reach 1.8% for the 5 mm collimator. The impact on output correction factors cancels in part, leading to a maximum confidence interval half width of 0.44%. The impact is less significant for percent-depth doses in comparison to dose profiles. For these types of measurement, in absolute terms and in comparison to the reference dose, confidence interval half widths less than or equal to 1.4% are observed. For simulated treatment plans, the impact is more significant for the treatment delivered with a smaller field size with confidence interval half widths reaching 2.5% and 1.4% for the 5 and 20 mm collimators, respectively. Significance. Results confirm that AAPM TG-157's tolerances cannot apply to the field sizes studied. This study provides an insight on the reachable dose calculation accuracy in a clinical setup.
Collapse
|
7
|
Didi S, Bahhous K, Zerfaoui M, Aboulbanine Z, Ouhadda H, Halimi A. Experimental validation of a linac head Geant4 model under a grid computing environment. Biomed Phys Eng Express 2022; 8. [DOI: 10.1088/2057-1976/ac4dd2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/21/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Background and purpose: This work aims to present the strategy to simulate a clinical linear accelerator based on the geometry provided by the manufacturer and summarize the corresponding experimental validation. Simulations were performed with the Geant4 Monte Carlo code under a grid computing environment. The objective of this contribution is reproducing therapeutic dose distributions in a water phantom with an accuracy less than 2%. Materials and methods: A Geant4 Monte Carlo model of an Elekta Synergy linear accelerator has been established, the simulations were launched in a large grid computing platform. Dose distributions are calculated for a 6 MV photon beam with treatment fields ranging from 5 × 5 cm2 to 20 × 20 cm 2 at a source - surface distance of 100 cm. Results: A high degree of agreement is achieved between the simulation results and the measured data, with dose differences of about 1.03% and 1.96% for the percentage depth dose curves and lateral dose profiles, respectively. This agreement is evaluated by the gamma index comparisons. Over 98% of the points for all simulations meet the restrictive acceptability criteria of 2%/2 mm. Conclusion: We have demonstrated the possibility to establish an accurate linac head Monte Carlo model for dose distribution simulations and quality assurance. Percentage depth dose curves and beam quality indices are in perfect agreement with the measured data with an accuracy of better than 2%.
Collapse
|
8
|
Feng B, Yu L, Mo E, Chen L, Zhao J, Wang J, Hu W. Evaluation of Daily CT for EPID-Based Transit In Vivo Dosimetry. Front Oncol 2021; 11:782263. [PMID: 34796120 PMCID: PMC8592931 DOI: 10.3389/fonc.2021.782263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 10/14/2021] [Indexed: 11/20/2022] Open
Abstract
Purpose The difference in anatomical structure and positioning between planning and treatment may lead to bias in electronic portal image device (EPID)-based in vivo dosimetry calculations. The purpose of this study was to use daily CT instead of planning CT as a reference for EPID-based in vivo dosimetry calculations and to analyze the necessity of using daily CT for EPID-based in vivo dosimetry calculations in terms of patient quality assurance. Materials and Methods Twenty patients were enrolled in this study. The study design included eight different sites (the cervical, nasopharyngeal, and oral cavities, rectum, prostate, bladder, lung, and esophagus). All treatments were delivered with a CT-linac 506c (UIH, Shanghai) using 6 MV photon beams. This machine is equipped with diagnosis-level fan-beam CT and an amorphous silicon EPID XRD1642 (Varex Imaging Corporation, UT, USA). A Monte Carlo algorithm was developed to calculate the transmit EPID image. A pretreatment measurement was performed to assess system accuracy by delivering based on a homogeneous phantom (RW3 slab, PTW, Freiburg). During treatment, each patient underwent CT scanning before delivery either once or twice for a total of 268 fractions obtained daily CT images. Patients may have had a position correction that followed our image-guided radiation therapy (IGRT) procedure. Meanwhile, transmit EPID images were acquired for each field during delivery. After treatment, all patient CTs were reviewed to ensure that there was no large anatomical change between planning and treatment. The reference of transmit EPID images was calculated based on both planning and daily CTs, and the IGRT correction was corrected for the EPID calculation. The gamma passing rate (3 mm 3%, 2 mm 3%, and 2 mm 2%) was calculated and compared between the planning CT and daily CT. Mechanical errors [ ± 1 mm, ± 2 mm, ± 5 mm multileaf collimator (MLC) systematic shift and 3%, 5% monitor unit (MU) scaling] were also introduced in this study for comparing detectability between both types of CT. Result The average (standard deviation) gamma passing rate (3 mm 3%, 2 mm 3%, and 2 mm 2%) in the RW3 slab phantom was 99.6% ± 1.0%, 98.9% ± 2.1%, and 97.2% ± 3.9%. For patient measurement, the average (standard deviation) gamma passing rates were 87.8% ± 14.0%, 82.2% ± 16.9%, and 74.2% ± 18.9% for using planning CTs as reference and 93.6% ± 8.2%, 89.7% ± 11.0%, and 82.8% ± 14.7% for using daily CTs as reference. There were significant differences between the planning CT and daily CT results. All p-values (Mann–Whitney test) were less than 0.001. In terms of error simulation, nonparametric test shows that there were significant differences between practical daily results and error simulation results (p < 0.001). The receiver operating characteristic (ROC) analysis indicated that the detectability of mechanical delivery error using daily CT was better than that of planning CT. AUCDaily CT = 0.63–0.96 and AUCPlanning CT = 0.49–0.93 in MLC systematic shift and AUCDaily CT = 0.56–0.82 and AUCPlanning CT = 0.45–0.73 in MU scaling. Conclusion This study shows the feasibility and effectiveness of using two-dimensional (2D) EPID portal image and daily CT-based in vivo dosimetry for intensity-modulated radiation therapy (IMRT) verification during treatment. The daily CT-based in vivo dosimetry has better sensitivity and specificity to identify the variation of IMRT in MLC-related and dose-related errors than planning CT-based.
Collapse
Affiliation(s)
- Bin Feng
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Lei Yu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Enwei Mo
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Liyuan Chen
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Jun Zhao
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Jiazhou Wang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| | - Weigang Hu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Radiation Oncology, Shanghai, China
| |
Collapse
|
9
|
Rahman M, Ashraf MR, Gladstone DJ, Bruza P, Jarvis LA, Schaner PE, Cao X, Pogue BW, Hoopes PJ, Zhang R. Treatment Planning System for Electron FLASH Radiotherapy: Open-source for Clinical Implementation. Int J Radiat Oncol Biol Phys 2021; 112:1023-1032. [PMID: 34762969 PMCID: PMC10386889 DOI: 10.1016/j.ijrobp.2021.10.148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/31/2021] [Accepted: 10/22/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE A Monte Carlo (MC) beam model and its implementation in a clinical treatment planning system (TPS, Varian Eclipse) are presented for a modified ultra-high dose-rate electron FLASH radiotherapy LINAC (eFLASH-RT) utilizing clinical accessories and geometry. METHODS The gantry head without scattering foils or targets, representative of the LINAC modifications, was modelled in Geant4-based GAMOS MC toolkit. The energy spectrum (σE) and beam source emittance cone angle (θcone) were varied to match the calculated open field central-axis percent depth dose (PDD) and lateral profiles with Gafchromic film measurements. The beam model and its Eclipse configuration were validated with measured profiles of the open field and nominal fields for clinical applicators. A MC forward dose calculation was conducted for a mouse whole brain treatment and an eFLASH-RT plan was compared to a conventional (Conv-RT) electron plan in Eclipse for a human patient with metastatic renal cell carcinoma. RESULTS The eFLASH beam model agreed best with measurements at σE=0.5 MeV and θcone=3.9±0.2 degrees. The model and its Eclipse configuration were validated to clinically acceptable accuracy (the absolute average error was within 1.5% for in-water lateral, 3% for in-air lateral, and 2% for PDD's). The forward calculation showed adequate dose delivery to the entire mouse brain, while sparing the organ-at-risk (lung). The human patient case demonstrated the planning capability with routine accessories to achieve an acceptable plan (90% of the tumor volume receiving 95% and 90% of the prescribed dose for eFLASH and conventional, respectively). CONCLUSION To the best of our knowledge, this is the first functional beam model commissioned in a clinical TPS for eFLASH-RT, enabling planning and evaluation with minimal deviation from Conv-RT workflow. It facilitates the clinical translation as eFLASH-RT and Conv-RT plan quality were comparable for a human patient involving complex geometries and tissue heterogeneity. The methods can be expanded to model other eFLASH irradiators with different beam characteristics.
Collapse
Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US.
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Lesley A Jarvis
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Philip E Schaner
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US; Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| |
Collapse
|
10
|
Detailed Monte Carlo analysis of the secondary photons coming out of the therapeutic X-ray beam of linear accelerator. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2021. [DOI: 10.2478/pjmpe-2021-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
External photon beam radiotherapy is often used in tumor treatment. The photons are generated from the target which had stricken by the primary electron beam (incident particles). The photon beam contains the primary photons coming directly from the target and secondary photons coming from the photon interactions with head component materials (scattered photons). Altogether is thereafter used in radiotherapy treatment. This Monte Carlo study aims to investigate and evaluate the secondary radiations (photons) in terms of fluence, energy fluence, spectral distribution, mean energy and angular spread distribution.
The secondary photons, which contributed in radiotherapy treatment, are examined and evaluated in number (fluence) and energy. At the phantom surface, the secondary photons originated in the whole linac head are mainly coming from the primary collimator. In 0.45% of secondary photons coming from the whole linac head, the primary collimator contributes by 86% and they are more energetic. However, the flattening filter and the secondary collimator contribute together by less than 14% and their photons are less energetic and then can deteriorate the beam dosimetry quality. To improve the radiotherapy treatment quality, the number of photons of low energy should be as low as possible in the clinical beam. Our work can be a basic investigation to use in the improvement of linac head configuration and specially the beam modifiers.
Collapse
|
11
|
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]
|
12
|
Zaragoza FJ, Eichmann M, Flühs D, Timmermann B, Brualla L. Monte Carlo Computation of Dose-Volume Histograms in Structures at Risk of an Eye Irradiated with Heterogeneous Ruthenium-106 Plaques. Ocul Oncol Pathol 2020; 6:353-359. [PMID: 33123529 DOI: 10.1159/000508113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/18/2020] [Indexed: 11/19/2022] Open
Abstract
Background/Aims The aim of this work is to compare Monte Carlo simulated absorbed dose distributions obtained from <sup>106</sup>Ru eye plaques, whose heterogeneous emitter distribution is known, with the common homogeneous approximation. The effect of these heterogeneities on segmented structures at risk is analyzed using an anthropomorphic phantom. Methods The generic CCA and CCB, with a homogeneous emitter map, and the specific CCA1364 and CCB1256 <sup>106</sup>Ru eye plaques are modeled with the Monte Carlo code PENELOPE. To compare the effect of the heterogeneities in the segmented volumes, cumulative dose-volume histograms are calculated for different rotations of the aforementioned plaques. Results For the cornea, the CCA with the equatorial placement yields the lowest absorbed dose rate while for the CCA1364 in the same placement the absorbed dose rate is 33% higher. The CCB1256 with the hot spot oriented towards the cornea yields the maximum dose rate per unit of activity while it is 44% lower for the CCB. Conclusions Dose calculations based on a homogeneous distribution of the emitter substance yield the lowest absorbed dose in the analyzed structures for all plaque placements. Treatment planning based on such calculations may result in an overdose of the structures at risk.
Collapse
Affiliation(s)
| | - Marion Eichmann
- Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
| | - Dirk Flühs
- NCTeam, Strahlenklinik, Universitätsklinikum Essen, Essen, Germany
| | - Beate Timmermann
- West German Proton Therapy Center Essen (WPE), Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), Essen, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Lorenzo Brualla
- West German Proton Therapy Center Essen (WPE), Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,University Hospital Essen, Essen, Germany
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Kumar S, Nahum AE, Chetty IJ. Monte-Carlo-computed dose, kerma and fluence distributions in heterogeneous slab geometries irradiated by small megavoltage photon fields. ACTA ACUST UNITED AC 2020; 65:175012. [DOI: 10.1088/1361-6560/ab98d1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
15
|
Negm H, Aly MMOM, Fathy WM. Modeling the head of PRIMUS linear accelerator for electron-mode at 10 MeV for different applicators. J Appl Clin Med Phys 2020; 21:134-141. [PMID: 32068335 PMCID: PMC7075389 DOI: 10.1002/acm2.12836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/02/2020] [Accepted: 01/28/2020] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE This study is to validate the utilization of Monte Carlo (MC) simulation to model the head of Primus linear accelerator, thereafter, using it to estimate the energy fluence distribution (EFD), the percentage depth dose (PDD), and beam profiles. MATERIALS AND METHODS The BEAMNRC code that is based on the EGSNRC code has been used for modeling the linear accelerator head for 10 MeV electron beam with different applicator sizes (10 × 10, 15 × 15, and 20 × 20 cm2 ). The phase space was acquired from BEAMNRC at the end of each applicator and then used as an input file to DOSXYZNRC and BEAMDP to calculate the EFD, PDD, and beam profiles. RESULTS There were a good consistency between the outcomes of the MC simulation and measured PDD and off-axis dose profiles that performed in a water phantom for all applicators. The PDD for the applicators proved to be favorable as a direct comparison of R100 , R90 , R80 , and R50 yielded results of < 2 mm, while it was 6 mm in R100 for the applicator 15 × 15 cm2 . The discrepancies in the surface doses (<3%) showed a quick decline in the build-up region and differences reached 0% within the first 2.4 mm. For the beam profiles comparison, the differences ranged from 2% (2 mm) to 3% (6 mm) for all applicators. CONCLUSION Our examination demonstrated that the MC simulation by BEAMNRC code was accurate in modeling the Primus linear accelerator head.
Collapse
Affiliation(s)
- Hani Negm
- Physics DepartmentCollege of ScienceJouf UniversitySakakaSaudi Arabia
- Physics DepartmentFaculty of ScienceAssiut UniversityAssiutEgypt
| | - Moamen M. O. M. Aly
- Radiotherapy and Nuclear Medicine DepartmentSouth Egypt Cancer InstituteAssiut UniversityAssiutEgypt
| | - Walaa M. Fathy
- Radiotherapy and Nuclear Medicine DepartmentSouth Egypt Cancer InstituteAssiut UniversityAssiutEgypt
| |
Collapse
|
16
|
Minibeam radiation therapy at a conventional irradiator: Dose-calculation engine and first tumor-bearing animals irradiation. Phys Med 2020; 69:256-261. [PMID: 31918378 DOI: 10.1016/j.ejmp.2019.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 01/31/2023] Open
Abstract
PURPOSE Minibeam radiation therapy (MBRT) is a novel therapeutic strategy, whose exploration was hindered due to its restriction to large synchrotrons. Our recent implementation of MBRT in a wide-spread small animal irradiator offers the possibility of performing systematic radiobiological studies. The aim of this research was to develop a set of dosimetric tools to reliably guide biological experiments in the irradiator. METHODS A Monte Carlo (Geant4)-based dose calculation engine was developed. It was then benchmarked against a series of dosimetric measurements performed with gafchromic films. Two voxelized rat phantoms (ROBY, computer tomography) were used to evaluate the treatment plan of F98 tumor-bearing rats. The response of a group of 7 animals receiving a unilateral irradiation of 58 Gy was compared to a group of non-irradiated controls. RESULTS The good agreement between calculations and the experimental data allowed the validation of the dose-calculation engine. The latter was first used to compare the dose distributions in computer tomography images of a rat's head and in a digital model of a rat's head (ROBY), obtaining a good general agreement. Finally, with respect to the in vivo experiment, the increase of mean survival time of the treated group with respect to the controls was modest but statistically significant. CONCLUSIONS The developed dosimetric tools were used to reliably guide the first MBRT treatments of intracranial glioma-bearing rats outside synchrotrons. The significant tumor response obtained with respect to the non-irradiated controls, despite the heterogenous dose coverage of the target, might indicate the participation of non-targeted effects.
Collapse
|
17
|
Sarıgül N, Yedekçi FY, Yeğiner M, Akyol F, Utku H. Determination of inflection points of CyberKnife dose profiles within acceptability criteria of deviations in measurements. Rep Pract Oncol Radiother 2020; 25:6-12. [DOI: 10.1016/j.rpor.2019.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/22/2019] [Accepted: 10/15/2019] [Indexed: 10/25/2022] Open
|
18
|
Ma CMC, Chetty IJ, Deng J, Faddegon B, Jiang SB, Li J, Seuntjens J, Siebers JV, Traneus E. Beam modeling and beam model commissioning for Monte Carlo dose calculation-based radiation therapy treatment planning: Report of AAPM Task Group 157. Med Phys 2019; 47:e1-e18. [PMID: 31679157 DOI: 10.1002/mp.13898] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 10/01/2019] [Accepted: 10/18/2019] [Indexed: 11/07/2022] Open
Abstract
Dose calculation plays an important role in the accuracy of radiotherapy treatment planning and beam delivery. The Monte Carlo (MC) method is capable of achieving the highest accuracy in radiotherapy dose calculation and has been implemented in many commercial systems for radiotherapy treatment planning. The objective of this task group was to assist clinical physicists with the potentially complex task of acceptance testing and commissioning MC-based treatment planning systems (TPS) for photon and electron beam dose calculations. This report provides an overview on the general approach of clinical implementation and testing of MC-based TPS with a specific focus on models of clinical photon and electron beams. Different types of beam models are described including those that utilize MC simulation of the treatment head and those that rely on analytical methods and measurements. The trade-off between accuracy and efficiency in the various source-modeling approaches is discussed together with guidelines for acceptance testing of MC-based TPS from the clinical standpoint. Specific recommendations are given on methods and practical procedures to commission clinical beam models for MC-based TPS.
Collapse
Affiliation(s)
- Chang Ming Charlie Ma
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Indrin J Chetty
- Radiation Oncology Department, Henry Ford Health System, Detroit, MI, 48188, USA
| | - Jun Deng
- Department of Therapeutic Radiology, Yale University, New Haven, CT, 06032, USA
| | - Bruce Faddegon
- Department of Radiation Oncology, UCSF, San Francisco, CA, 94143, USA
| | - Steve B Jiang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Jan Seuntjens
- Medical Physics Unit, McGill University, Montreal, QC, H4A 3J1, Canada
| | - Jeffrey V Siebers
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Erik Traneus
- RaySearch Laboratories AB, SE-103 65, Stockholm, Sweden
| |
Collapse
|
19
|
Focused very high-energy electron beams as a novel radiotherapy modality for producing high-dose volumetric elements. Sci Rep 2019; 9:10837. [PMID: 31346184 PMCID: PMC6658670 DOI: 10.1038/s41598-019-46630-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 07/01/2019] [Indexed: 12/12/2022] Open
Abstract
The increased inertia of very high-energy electrons (VHEEs) due to relativistic effects reduces scattering and enables irradiation of deep-seated tumours. However, entrance and exit doses are high for collimated or diverging beams. Here, we perform a study based on Monte Carlo simulations of focused VHEE beams in a water phantom, showing that dose can be concentrated into a small, well-defined volumetric element, which can be shaped or scanned to treat deep-seated tumours. The dose to surrounding tissue is distributed over a larger volume, which reduces peak surface and exit doses for a single beam by more than one order of magnitude compared with a collimated beam.
Collapse
|
20
|
Lin T, Ni X, Gao L, Sui J, Xie K, Chang S. Evaluation of the Effect of a Tracheal Stent on Radiation Dose Distribution via Micro-CT Imaging. Technol Cancer Res Treat 2019; 18:1533033819844485. [PMID: 31010405 PMCID: PMC6480982 DOI: 10.1177/1533033819844485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To study the effect of a metal tracheal stent on radiation dose distribution. METHOD A metal tube bracket is placed in a self-made foam tube sleeve, and micro-computed tomography scanning is performed directly. The foam sleeve containing the metal bracket is placed in a nonuniform phantom for a routine computed tomography scan. The stents in conventional computed tomography images are replaced by the stents in micro-computed tomography images. Subsequently, 2 sets of computed tomography images are obtained and then imported to a radiotherapy treatment planning system. A single photon beam at 0° is designed in a field size of 10 cm × 10 cm, a photon beam of 6 MV, and a monitor unit of 200 MU. Monte Carlo algorithm is used to calculate the dose distribution and obtain the dose curve of the central axis of the field. The dose is verified with thermoluminescence dose tablets. RESULTS The micro-computed tomography images of the tracheal stent are clearer and less false-like than its conventional computed tomography images. The planned dose curves of the 2 groups are similar. In comparison with the images without any stents in place, the doses at the incident surface of the stent in the conventional computed tomography images and at the stent exit surface in the rear of the stent increase by 1.86% and 2.76%, respectively. In the micro-computed tomography images, the doses at the incident surface of the stent and at the exit surface behind the stent increase by 1.32% and 1.19%, respectively. Conventional computed tomography reveals a large deviation between the measured and calculated values. CONCLUSION Tracheal stent based on micro-computed tomography imaging has a less effect on radiotherapy calculation than that based on conventional computed tomography imaging.
Collapse
Affiliation(s)
- Tao Lin
- 1 College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China.,2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,3 The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Xinye Ni
- 2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,3 The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Liugang Gao
- 2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,3 The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Jianfeng Sui
- 2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,3 The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Kai Xie
- 2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.,3 The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Shuquan Chang
- 1 College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| |
Collapse
|
21
|
Najafzadeh M, Hoseini-Ghafarokhi M, Bolagh RSM, Haghparast M, Zarifi S, Nickfarjam A, Farhood B, Chow JCL. Benchmarking of Monte Carlo model of Siemens Oncor® linear accelerator for 18MV photon beam: Determination of initial electron beam parameters. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2019; 27:1047-1070. [PMID: 31498147 DOI: 10.3233/xst-190568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
OBJECTIVE This study aims to benchmark a Monte Carlo (MC) model of the 18 MV photon beam produced by the Siemens Oncor® linac using the BEAMnrc and DOSXYZnrc codes. METHODS By matching the percentage depth doses and beam profiles calculated by MC simulations with measurements, the initial electron beam parameters including electron energy, full width at half maximum (spatial FWHM), and mean angular spread were derived for the 10×10 cm2 and 20×20 cm2 field sizes. The MC model of the 18 MV photon beam was then validated against the measurements for different field sizes (5×5, 30×30 and 40×40 cm2) by gamma index analysis. RESULTS The optimum values for electron energy, spatial FWHM and mean angular spread were 14.2 MeV, 0.08 cm and 0.8 degree, respectively. The MC simulations yielded the comparable measurement results of these optimum parameters. The gamma passing rates (with acceptance criteria of 1% /1 mm) for percentage depth doses were found to be 100% for all field sizes. For cross-line profiles, the gamma passing rates were 100%, 97%, 95%, 96% and 95% for 5×5, 10×10, 20×20, 30×30 and 40×40 cm2 field sizes, respectively. CONCLUSIONS By validation of the MC model of Siemens Oncor® linac using various field sizes, it was found that both dose profiles of small and large field sizes were very sensitive to the changes in spatial FWHM and mean angular spread of the primary electron beam from the bending magnet. Hence, it is recommended that both small and large field sizes of the 18 MV photon beams should be considered in the Monte Carlo linac modeling.
Collapse
Affiliation(s)
- Milad Najafzadeh
- Department of Radiology, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare-Abbas, Iran
| | - Mojtaba Hoseini-Ghafarokhi
- Department of Radiology and Nuclear Medicine, School of Para Medical Science, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Mohammad Haghparast
- Department of Radiology, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare-Abbas, Iran
| | - Shiva Zarifi
- Department of Medical Physics, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Abolfazl Nickfarjam
- Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Bagher Farhood
- Department of Medical Physics and Radiology, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - James C L Chow
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| |
Collapse
|
22
|
Dosimetric evaluation of a novel electron–photon mixed beam, produced by a medical linear accelerator. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396917000711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractAimThis study deals with the characteristics of simultaneous photon and electron beams in homogenous and inhomogeneous phantoms by experimental and Monte Carlo dosimetry, for therapeutic purposes. Materials and methods: Both 16 and 20 MeV high-energy electron beams were used as the original beam to strike perforated lead sheets to produce the mixed beam. The dosimetry results were achieved by measurement in an ion chamber in a water phantom and film dosimetry in a Perspex nasal phantom, and then compared with those calculated through a simulation approach. To evaluate two-dimensional dose distribution in the inhomogeneous medium, the dose–area histogram was obtained.ResultsThe highest percentage of photon contribution in mixed beam was found to be 36% for 2-mm thickness of lead layer with holes diameter of 0·2 cm for a 20 MeV primary electron energy. For small fields, the percentage depth dose parameters variations were found to be similar to pure electron beam within ±2%. The most feasible flatness in beam profile was 11% for pure electron and 7% for the mixed beam. Penumbra changes as function of depth was about ten times better than in pure electron field.ConclusionsThe results present some dosimetric advantages that can make this study a platform for the production of simultaneous mixed beams in future linear accelerators (LINACs), which through redesign of the LINAC head, which could lead to setup error reduction and a decrease of intra-fractional tumour cells repair.
Collapse
|
23
|
Esposito A, Silva S, Oliveira J, Lencart J, Santos J. Primo software as a tool for Monte Carlo simulations of intensity modulated radiotherapy: a feasibility study. Radiat Oncol 2018; 13:91. [PMID: 29764449 PMCID: PMC5952624 DOI: 10.1186/s13014-018-1021-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/11/2018] [Indexed: 11/23/2022] Open
Abstract
Background IMRT provides higher dose conformation to the target and dose sparing to surrounding tissues than 3DCRT. Monte Carlo method in Medical Physics is not a novelty to approach dosimetric problems. A new PENELOPE based code named PRIMO recently was published. The most intriguing features of PRIMO are the user-friendly approach, the stand-alone property and the built-in definition of different linear accelerators models. Nevertheless, IMRT simulations are not yet implemented. Methods A Varian Trilogy with a Millennium120 MLC and a Varian Novalis with 120HD MLC were studied. A RW3 multi-slab phantom was irradiated with Gafchromic films inserted between slabs. An Expression 10000XL scanner (Seiko Epson Corp., Nagano, Japan) was used to digitalize the films. PTW-Verisoft software using the global Gamma Function (2%, 2 mm) was used to compare simulated and experimental results. The primary beam parameters were adjusted to best match reference data previously obtained in a water phantom. Static MLC simulations were performed to validate the MLC models in use. Two Dynamic IMRT preliminary tests were performed with leaves moving with constant and variable speed. A further test of an in phantom delivery of a real IMRT field allowed simulating a clinical-like MLC modulation. Results Simulated PDD, X- and Y-profiles in reference conditions showed respectively 100.0%, 100.0% and 99.4% of Gamma points < 1 (2%, 2 mm). Static MLC simulations showed 100.0% of Gamma points < 1 with the 120HD MLC and 99.1% with the Millennium compared with the scanned images. The fixed speed test showed 99.5 and 98.9% of Gamma points < 1 respectively with two different MLC configuration-sampling algorithms when the 120HD MLC was used. The higher modulation MLC motion simulation showed 99.1% of Gamma points < 1 with respect to the experimental. This result depends on the number of the fields to reproduce the MLC motion, as well as calculation time. The clinical-like simulation showed 96.2% of Gamma points < 1 using the same analysis conditions. Conclusions The numerical model of the Varian Trilogy and Novalis in the PRIMO software was validated. The algorithms to simulate MLC motion were considered reliable. A clinical-like procedure was successfully simulated.
Collapse
Affiliation(s)
- Alessandro Esposito
- Radiation Oncology Department, Princess Alexandra Hospital, Brisbane, Australia.
| | - Sofia Silva
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto, Porto, Portugal.,Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Medical Physics Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Jorge Oliveira
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto, Porto, Portugal.,Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Joana Lencart
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto, Porto, Portugal.,Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Medical Physics Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - João Santos
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto, Porto, Portugal.,Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Medical Physics Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
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: 27] [Impact Index Per Article: 4.5] [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.
Collapse
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
| |
Collapse
|
26
|
Arce P, Lagares JI. CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS. Phys Med Biol 2018; 63:035007. [PMID: 29256451 DOI: 10.1088/1361-6560/aaa2b0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN Clinac 2100 C/D linear accelerator by the procedure of adjusting the initial beam parameters to fit the percentage depth dose and cross-profile dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2 × 2 cm2 to 40 × 40 cm2, a small phantom voxel size and high statistics, fine precision in the determination of the beam parameters has been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. Standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple-scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting, a comprehensive CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.
Collapse
Affiliation(s)
- Pedro Arce
- Technology Department, Scientific Instrumentation Division, Medical Applications Unit, Centro de Investigaciones Energéticas, MedioAmbientales y Tecnológicas (CIEMAT), Madrid, Spain
| | | |
Collapse
|
27
|
Takada K, Sato T, Kumada H, Koketsu J, Takei H, Sakurai H, Sakae T. Validation of the physical and RBE-weighted dose estimator based on PHITS coupled with a microdosimetric kinetic model for proton therapy. JOURNAL OF RADIATION RESEARCH 2018; 59:91-99. [PMID: 29087492 PMCID: PMC5778494 DOI: 10.1093/jrr/rrx057] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/13/2017] [Indexed: 06/07/2023]
Abstract
The microdosimetric kinetic model (MKM) is widely used for estimating relative biological effectiveness (RBE)-weighted doses for various radiotherapies because it can determine the surviving fraction of irradiated cells based on only the lineal energy distribution, and it is independent of the radiation type and ion species. However, the applicability of the method to proton therapy has not yet been investigated thoroughly. In this study, we validated the RBE-weighted dose calculated by the MKM in tandem with the Monte Carlo code PHITS for proton therapy by considering the complete simulation geometry of the clinical proton beam line. The physical dose, lineal energy distribution, and RBE-weighted dose for a 155 MeV mono-energetic and spread-out Bragg peak (SOBP) beam of 60 mm width were evaluated. In estimating the physical dose, the calculated depth dose distribution by irradiating the mono-energetic beam using PHITS was consistent with the data measured by a diode detector. A maximum difference of 3.1% in the depth distribution was observed for the SOBP beam. In the RBE-weighted dose validation, the calculated lineal energy distributions generally agreed well with the published measurement data. The calculated and measured RBE-weighted doses were in excellent agreement, except at the Bragg peak region of the mono-energetic beam, where the calculation overestimated the measured data by ~15%. This research has provided a computational microdosimetric approach based on a combination of PHITS and MKM for typical clinical proton beams. The developed RBE-estimator function has potential application in the treatment planning system for various radiotherapies.
Collapse
Affiliation(s)
- Kenta Takada
- Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Tatsuhiko Sato
- Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki 319-1195, Japan
| | - Hiroaki Kumada
- Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
- Proton Beam Therapy Center, University of Tsukuba Hospital, 2-1-1, Amakubo, Tsukuba, Ibaraki, 305-8576, Japan
| | - Junichi Koketsu
- Proton Beam Therapy Center, University of Tsukuba Hospital, 2-1-1, Amakubo, Tsukuba, Ibaraki, 305-8576, Japan
| | - Hideyuki Takei
- Proton Beam Therapy Center, University of Tsukuba Hospital, 2-1-1, Amakubo, Tsukuba, Ibaraki, 305-8576, Japan
| | - Hideyuki Sakurai
- Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
- Proton Beam Therapy Center, University of Tsukuba Hospital, 2-1-1, Amakubo, Tsukuba, Ibaraki, 305-8576, Japan
| | - Takeji Sakae
- Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
- Proton Beam Therapy Center, University of Tsukuba Hospital, 2-1-1, Amakubo, Tsukuba, Ibaraki, 305-8576, Japan
| |
Collapse
|
28
|
Lebredonchel S, Lacornerie T, Rault E, Wagner A, Reynaert N, Crop F. About the non-consistency of PTV-based prescription in lung. Phys Med 2017; 44:177-187. [DOI: 10.1016/j.ejmp.2017.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/16/2017] [Accepted: 03/18/2017] [Indexed: 12/31/2022] Open
|
29
|
High performance modelling of the transport of energetic particles for photon radiotherapy. Phys Med 2017; 42:305-312. [PMID: 28673482 DOI: 10.1016/j.ejmp.2017.06.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 06/20/2017] [Accepted: 06/24/2017] [Indexed: 11/22/2022] Open
Abstract
This work consists of the validation of a new Grid Based Boltzmann Solver (GBBS) conceived for the description of the transport and energy deposition by energetic particles for radiotherapy purposes. The entropic closure and a compact mathematical formulation allow our code (M1) to calculate the delivered dose with an accuracy comparable to the Monte-Carlo (MC) codes with a computational time that is reduced to the order of few minutes without any special processing power requirement. A validation protocol with heterogeneity inserts has been defined for different photon sources. The comparison with the MC calculated depth-dose curves and transverse profiles of the beam at different depths shows an excellent accuracy of the M1 model.
Collapse
|
30
|
Narayanasamy G, Saenz DL, Defoor D, Papanikolaou N, Stathakis S. Dosimetric validation of Monaco treatment planning system on an Elekta VersaHD linear accelerator. J Appl Clin Med Phys 2017; 18:123-129. [PMID: 28944979 PMCID: PMC5689924 DOI: 10.1002/acm2.12188] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/26/2017] [Accepted: 08/22/2017] [Indexed: 11/12/2022] Open
Abstract
The purpose of this study is to perform dosimetric validation of Monaco treatment planning system version 5.1. The Elekta VersaHD linear accelerator with high dose rate flattening filter‐free photon modes and electron energies was used in this study. The dosimetric output of the new Agility head combined with the FFF photon modes warranted this investigation into the dosimetric accuracy prior to clinical usage. A model of the VersaHD linac was created in Monaco TPS by Elekta using commissioned beam data including percent depth dose curves, beam profiles, and output factors. A variety of 3D conformal fields were created in Monaco TPS on a combined Plastic water/Styrofoam phantom and validated against measurements with a calibrated ion chamber. Some of the parameters varied including source to surface distance, field size, wedges, gantry angle, and depth for all photon and electron energies. In addition, a series of step and shoot IMRT, VMAT test plans, and patient plans on various anatomical sites were verified against measurements on a Delta4 diode array. The agreement in point dose measurements was within 2% for all photon and electron energies in the homogeneous phantom and within 3% for photon energies in the heterogeneous phantom. The mean ± SD gamma passing rates of IMRT test fields yielded 93.8 ± 4.7% based on 2% dose difference and 2 mm distance‐to‐agreement criteria. Eight previously treated IMRT patient plans were replanned in Monaco TPS and five measurements on each yielded an average gamma passing rate of 95% with 6.7% confidence limit based on 3%, 3 mm gamma criteria. This investigation on dosimetric validation ensures accuracy of modeling VersaHD linac in Monaco TPS thereby improving patient safety.
Collapse
Affiliation(s)
- Ganesh Narayanasamy
- Department of Radiation Oncology, University of Texas Health San Antonio, San Antonio, TX, USA.,Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Daniel L Saenz
- Department of Radiation Oncology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Dewayne Defoor
- Department of Radiation Oncology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Niko Papanikolaou
- Department of Radiation Oncology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Sotirios Stathakis
- Department of Radiation Oncology, University of Texas Health San Antonio, San Antonio, TX, USA
| |
Collapse
|
31
|
Papadimitroulas P. Dosimetry applications in GATE Monte Carlo toolkit. Phys Med 2017; 41:136-140. [DOI: 10.1016/j.ejmp.2017.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 10/20/2022] Open
|
32
|
Wagner A, Crop F, Mirabel X, Tailly C, Reynaert N. Use of an in-house Monte Carlo platform to assess the clinical impact of algorithm-related dose differences on DVH constraints. Phys Med 2017; 42:319-326. [PMID: 28662849 DOI: 10.1016/j.ejmp.2017.05.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/18/2017] [Accepted: 05/18/2017] [Indexed: 10/19/2022] Open
Abstract
PURPOSE The aim of the present work is to evaluate a semi-automatic prescription and validation system of treatment plans for complex delivery techniques, integrated in a Monte Carlo platform, and to investigate the clinical impact of dose differences due to the calculation algorithms, by assessing the changes in DVH constraints. METHODS A new prescription module was implemented into the Moderato system, an in-house Monte Carlo platform, with corresponding dose constraints generated depending on the anatomical region and fractionation scheme considered. The platform was tested on 83 cases treated with Cyberknife and Tomotherapy machines, to assess whether dose variations between the re-calculated dose and the Treatment Planning System might impact the dose constraints on the sensitive structures. RESULTS Dose differences were small (within 3%) between calculation algorithms in most of the thoracic, pelvic and abdominal cases, both for the Cyberknife and Tomotherapy machines. On the other hand, spinal and head and neck treatments presented a few significant dose deviations for constraints on small volumes, such as the optic pathways and the spinal cord. These differences range from -11% to +6%, inducing constraint violations of up to 8% over the dose limit. CONCLUSIONS The Moderato platform offers an interesting tool for plan quality validation, with a prescription module highlighting crucial features in the structures list, and a Monte Carlo dose re-calculation for complex modern techniques. Due to the high number of warnings appearing in some situations, display optimization is required in practice.
Collapse
Affiliation(s)
- A Wagner
- Department of Medical Physics, Centre Oscar Lambret and University Lille 1, France
| | - F Crop
- Department of Medical Physics, Centre Oscar Lambret and University Lille 1, France
| | - X Mirabel
- Academic Department of Radiation Oncology, Centre Oscar Lambret and University Lille 2, France
| | - C Tailly
- Department of Medical Physics, Centre Oscar Lambret and University Lille 1, France
| | - N Reynaert
- Department of Medical Physics, Centre Oscar Lambret and University Lille 1, France
| |
Collapse
|
33
|
Comparison of Flattening Filter (FF) and Flattening-Filter-Free (FFF) 6 MV photon beam characteristics for small field dosimetry using EGSnrc Monte Carlo code. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.02.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
34
|
Effects of density from various hip prosthesis materials on 6 MV photon beam: a Monte Carlo study. JOURNAL OF RADIOTHERAPY IN PRACTICE 2017. [DOI: 10.1017/s1460396917000012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractIn radiotherapy planning, computed tomography (CT) images are used to calculate the dose in the patient. However, a high density hip prosthesis can cause streaking artefacts in CT images, which make dose calculations for nearby organs inaccurate. This study aim to quantify the impact of a hip prosthesis on 6 MV photon beam dose distribution using the Monte Carlo (MC) simulation. To quantify the radiation dose at the hip prosthesis accurately, image processing techniques were used to generate CT images free from streak artefacts. MATLAB software was used to produce computer-generated phantoms consisting of bone, titanium, stainless steel and CoCrMo. Percentage depth dose (PDD) and beam profile were used to analyse the impact of the hip prosthesis on the dose distribution of the photon beam. PDD showed that the absorbed dose was reduced as the density of the material increased, and the dose was reduced by as much as 49% when the photon beam struck the highest density material (CoCrMo, 8·2g/cm3). However, dose was increased at the tissue-hip prosthesis interface (depths of 4 and 19cm). As the depth increased, the absorbed dose decreased due to attenuation of photons by the tissue and the metal.
Collapse
|
35
|
Lloyd SAM, Gagne IM, Bazalova-Carter M, Zavgorodni S. Measured and Monte Carlo simulated electron backscatter to the monitor chamber for the Varian TrueBeam Linac. Phys Med Biol 2016; 61:8779-8793. [PMID: 27897141 DOI: 10.1088/1361-6560/61/24/8779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To accurately simulate therapeutic electron beams using Monte Carlo methods, backscatter from jaws into the monitor chamber must be accounted for via the backscatter factor, S b. Measured and simulated values of S b for the TrueBeam are investigated. Two approaches for measuring S b are presented. Both require service mode operation with the dose and pulse forming networking servos turned off in order to assess changes in dose rate with field size. The first approach samples an instantaneous dose rate, while the second approach times the delivery of a fixed number of monitor units to assess dose rate. Dose rates were measured for 6, 12 and 20 MeV electrons for jaw- or MLC-shaped apertures between [Formula: see text] and [Formula: see text] cm2. The measurement techniques resulted in values of S b that agreed within 0.21% for square and asymmetric fields collimated by the jaws. Measured values of S b were used to calculate the forward dose component in a virtual monitor chamber using BEAMnrc. Based on this forward component, simulated values of S b were calculated and compared to measurement and Varian's VirtuaLinac simulations. BEAMnrc results for jaw-shaped fields agreed with measurements and with VirtuaLinac simulations within 0.2%. For MLC-shaped fields, the respective measurement techniques differed by as much as 0.41% and BEAMnrc results differed with measurement by as much as 0.4%, however, all measured and simulated values agreed within experimental uncertainty. Measurement sensitivity was not sufficient to capture the small backscatter effect due to the MLC, and Monte Carlo predicted backscatter from the MLC to be no more than 0.3%. Backscatter from the jaws changed the electron dose rate by up to 2.6%. This reinforces the importance of including a backscatter factor in simulations of electron fields shaped with secondary collimating jaws, but presents the option of ignoring it when jaws are retracted and collimation is done with the MLC.
Collapse
Affiliation(s)
- Samantha A M Lloyd
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | | | | | | |
Collapse
|
36
|
Brualla L, Rodriguez M, Lallena AM. Monte Carlo systems used for treatment planning and dose verification. Strahlenther Onkol 2016; 193:243-259. [PMID: 27888282 DOI: 10.1007/s00066-016-1075-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 10/25/2016] [Indexed: 11/28/2022]
Abstract
General-purpose radiation transport Monte Carlo codes have been used for estimation of the absorbed dose distribution in external photon and electron beam radiotherapy patients since several decades. Results obtained with these codes are usually more accurate than those provided by treatment planning systems based on non-stochastic methods. Traditionally, absorbed dose computations based on general-purpose Monte Carlo codes have been used only for research, owing to the difficulties associated with setting up a simulation and the long computation time required. To take advantage of radiation transport Monte Carlo codes applied to routine clinical practice, researchers and private companies have developed treatment planning and dose verification systems that are partly or fully based on fast Monte Carlo algorithms. This review presents a comprehensive list of the currently existing Monte Carlo systems that can be used to calculate or verify an external photon and electron beam radiotherapy treatment plan. Particular attention is given to those systems that are distributed, either freely or commercially, and that do not require programming tasks from the end user. These systems are compared in terms of features and the simulation time required to compute a set of benchmark calculations.
Collapse
Affiliation(s)
- Lorenzo Brualla
- NCTeam, Strahlenklinik, Universitätsklinikum Essen, Hufelandstraße 55, D-45122, Essen, Germany.
| | | | - Antonio M Lallena
- Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, E-18071, Granada, Spain
| |
Collapse
|
37
|
Reynaert N, Demol B, Charoy M, Bouchoucha S, Crop F, Wagner A, Lacornerie T, Dubus F, Rault E, Comte P, Cayez R, Boydev C, Pasquier D, Mirabel X, Lartigau E, Sarrazin T. Clinical implementation of a Monte Carlo based treatment plan QA platform for validation of Cyberknife and Tomotherapy treatments. Phys Med 2016; 32:1225-1237. [DOI: 10.1016/j.ejmp.2016.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022] Open
|
38
|
Sterpin E, Barragan A, Souris K, Lee JA. [Robust treatment planning in proton therapy]. Cancer Radiother 2016; 20:523-9. [PMID: 27614528 DOI: 10.1016/j.canrad.2016.07.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 07/19/2016] [Indexed: 11/28/2022]
Abstract
The concentration of the dose delivered by protons at the end of their path, the Bragg peak, has the potential to improve external radiotherapy treatments. Unfortunately, the main strength of the protons, their finite range, is also their greatest weakness. Any uncertainty on the range may lead to inadequate target coverage or excessive toxicity. The uncertainties have multiple origins and include, among others, ballistic errors, morphological modifications or inaccurate estimations of the physical quantities necessary to predict the proton range. Uncertainties have been part of daily practice in conventional radiotherapy with X-rays for a long time. However, dose distributions delivered with X-rays are much less sensitive to uncertainties than the ones delivered with protons. This relative insensitivity enabled the management of uncertainties through safety margins using a simple formalism. The conditions of validity of this formalism are much more restrictive for proton therapy, leading to the need of developing new tools and adapted strategies to manage accurately these uncertainties. The objective of this paper is to present a vision for the management of uncertainties in proton therapy in the continuity of formalisms established for X-rays. The latter are first summarized before discussing the necessary developments in order to consistently apply them to protons.
Collapse
Affiliation(s)
- E Sterpin
- Katholieke Universiteit Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, O&N I Herestraat 49, 3000 Leuven, Belgique; Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, institut de recherche expérimentale et clinique, avenue Hippocrate 54, 1200 Brussels, Belgique.
| | - A Barragan
- Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, institut de recherche expérimentale et clinique, avenue Hippocrate 54, 1200 Brussels, Belgique
| | - K Souris
- Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, institut de recherche expérimentale et clinique, avenue Hippocrate 54, 1200 Brussels, Belgique
| | - J A Lee
- Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, institut de recherche expérimentale et clinique, avenue Hippocrate 54, 1200 Brussels, Belgique
| |
Collapse
|
39
|
Sterpin E. Potential pitfalls of the PTV concept in dose-to-medium planning optimization. Phys Med 2016; 32:1103-10. [PMID: 27546868 DOI: 10.1016/j.ejmp.2016.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 12/25/2022] Open
|
40
|
Lloyd SAM, Gagne IM, Bazalova-Carter M, Zavgorodni S. Validation of Varian TrueBeam electron phase-spaces for Monte Carlo simulation of MLC-shaped fields. Med Phys 2016; 43:2894-2903. [PMID: 27277038 DOI: 10.1118/1.4949000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE This work evaluates Varian's electron phase-space sources for Monte Carlo simulation of the TrueBeam for modulated electron radiation therapy (MERT) and combined, modulated photon and electron radiation therapy (MPERT) where fields are shaped by the photon multileaf collimator (MLC) and delivered at 70 cm SSD. METHODS Monte Carlo simulations performed with EGSnrc-based BEAMnrc/DOSXYZnrc and penelope-based PRIMO are compared against diode measurements for 5 × 5, 10 × 10, and 20 × 20 cm(2) MLC-shaped fields delivered with 6, 12, and 20 MeV electrons at 70 cm SSD (jaws set to 40 × 40 cm(2)). Depth dose curves and profiles are examined. In addition, EGSnrc-based simulations of relative output as a function of MLC-field size and jaw-position are compared against ion chamber measurements for MLC-shaped fields between 3 × 3 and 25 × 25 cm(2) and jaw positions that range from the MLC-field size to 40 × 40 cm(2). RESULTS Percent depth dose curves generated by BEAMnrc/DOSXYZnrc and PRIMO agree with measurement within 2%, 2 mm except for PRIMO's 12 MeV, 20 × 20 cm(2) field where 90% of dose points agree within 2%, 2 mm. Without the distance to agreement, differences between measurement and simulation are as large as 7.3%. Characterization of simulated dose parameters such as FWHM, penumbra width and depths of 90%, 80%, 50%, and 20% dose agree within 2 mm of measurement for all fields except for the FWHM of the 6 MeV, 20 × 20 cm(2) field which falls within 2 mm distance to agreement. Differences between simulation and measurement exist in the profile shoulders and penumbra tails, in particular for 10 × 10 and 20 × 20 cm(2) fields of 20 MeV electrons, where both sets of simulated data fall short of measurement by as much as 3.5%. BEAMnrc/DOSXYZnrc simulated outputs agree with measurement within 2.3% except for 6 MeV MLC-shaped fields. Discrepancies here are as great as 5.5%. CONCLUSIONS TrueBeam electron phase-spaces available from Varian have been implemented in two distinct Monte Carlo simulation packages to produce dose distributions and outputs that largely reflect measurement. Differences exist in the profile shoulders and penumbra tails for the 20 MeV phase-space off-axis and in the outputs for the 6 MeV phase-space.
Collapse
Affiliation(s)
- Samantha A M Lloyd
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 3P6 5C2, Canada
| | - Isabelle M Gagne
- Department of Medical Physics, BC Cancer Agency-Vancouver Island Centre, Victoria, British Columbia V8R 6V5, Canada and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2, Canada
| | - Magdalena Bazalova-Carter
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2, Canada
| | - Sergei Zavgorodni
- Department of Medical Physics, BC Cancer Agency-Vancouver Island Centre, Victoria, British Columbia V8R 6V5, Canada and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2, Canada
| |
Collapse
|
41
|
Kang KM, Jeong BK, Choi HS, Song JH, Park BD, Lim YK, Jeong H. Effectiveness of the Monte Carlo method in stereotactic radiation therapy applied to quasi-homogenous brain tumors. Oncotarget 2016; 7:12662-71. [PMID: 26871473 PMCID: PMC4914312 DOI: 10.18632/oncotarget.7280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/23/2016] [Indexed: 11/30/2022] Open
Abstract
This study was aimed to evaluate the effectiveness of Monte Carlo (MC) method in stereotactic radiotherapy for brain tumor. The difference in doses predicted by the conventional Ray-tracing (Ray) and the advanced MC algorithms was comprehensively investigated through the simulations for phantom and patient data, actual measurement of dose distribution, and the retrospective analysis of 77 brain tumors patients. These investigations consistently showed that the MC algorithm overestimated the dose than the Ray algorithm and the MC overestimation was generally increased as decreasing the beams size and increasing the number of beams delivered. These results demonstrated that the advanced MC algorithm would be inaccurate than the conventional Raytracing algorithm when applied to a (quasi-) homogeneous brain tumors. Thus, caution may be needed to apply the MC method to brain radiosurgery or radiotherapy.
Collapse
Affiliation(s)
- Ki Mun Kang
- Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Bae Kwon Jeong
- Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Hoon Sik Choi
- Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Jin Ho Song
- Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Byung-Do Park
- Department of Radiation Oncology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Hojin Jeong
- Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
| |
Collapse
|
42
|
Aslam A, Kakakhel MB, Shahid SA, Younas L, Zareen S. Soft tissue and water substitutes for megavoltage photon beams: An EGSnrc-based evaluation. J Appl Clin Med Phys 2016; 17:408-415. [PMID: 26894338 PMCID: PMC5690209 DOI: 10.1120/jacmp.v17i1.5700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 08/24/2015] [Accepted: 08/22/2015] [Indexed: 11/29/2022] Open
Abstract
In this work, soft‐tissue equivalence of water, polystyrene, PMMA and water equivalence of polystyrene, and PMMA has been assessed for multiple megavoltage photon beams and field sizes. EGSnrc based Monte Carlo (MC) codes, BEAMnrc and DOSXYZnrc are used for the linac head modeling and the phantom dose calculations, respectively. Percentage depth doses (PDDs) are scored for two field sizes (5×5 cm2, 10×10 cm2) and photon energies (6 MV and 10 MV) in water, polystyrene, PMMA, and soft tissue. The comparisons of PDDs show that soft‐tissue equivalence of various materials varies with the depth in the phantom, field size, and photon energy. Water and PMMA are found to be the closest soft‐tissue and water substitutes, respectively. Soft‐tissue and water equivalence of dosimetry materials need to be evaluated for a range of photon energies and field sizes before their application in complex radiation beams. PACS numbers: 87.55.Gh, 87.55.K‐
Collapse
|
43
|
Tumour Movement in Proton Therapy: Solutions and Remaining Questions: A Review. Cancers (Basel) 2015; 7:1143-53. [PMID: 26132317 PMCID: PMC4586762 DOI: 10.3390/cancers7030829] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 06/10/2015] [Accepted: 06/18/2015] [Indexed: 12/25/2022] Open
Abstract
Movement of tumours, mostly by respiration, has been a major problem for treating lung cancer, liver tumours and other locations in the abdomen and thorax. Organ motion is indeed one component of geometrical uncertainties that includes delineation and target definition uncertainties, microscopic disease and setup errors. At present, minimising motion seems to be the easiest to implement in clinical practice. If combined with adaptive approaches to correct for gradual anatomical variations, it may be a practical strategy. Other approaches such as repainting and tracking could increase the accuracy of proton therapy delivery, but advanced 4D solutions are needed. Moreover, there is a need to perform clinical studies to investigate which approach is the best in a given clinical situation. The good news is that existing and emerging technology and treatment planning systems as will without doubt lead in the forthcoming future to practical solutions to tackle intra-fraction motion in proton therapy. These developments may also improve motion management in photon therapy as well.
Collapse
|
44
|
Sarrut D, Bardiès M, Boussion N, Freud N, Jan S, Létang JM, Loudos G, Maigne L, Marcatili S, Mauxion T, Papadimitroulas P, Perrot Y, Pietrzyk U, Robert C, Schaart DR, Visvikis D, Buvat I. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications. Med Phys 2015; 41:064301. [PMID: 24877844 DOI: 10.1118/1.4871617] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same framework is emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities.
Collapse
Affiliation(s)
- David Sarrut
- Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1; Centre Léon Bérard, France
| | - Manuel Bardiès
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | | | - Nicolas Freud
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon, France
| | | | - Jean-Michel Létang
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon, France
| | - George Loudos
- Department of Medical Instruments Technology, Technological Educational Institute of Athens, Athens 12210, Greece
| | - Lydia Maigne
- UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière, France
| | - Sara Marcatili
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | - Thibault Mauxion
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | - Panagiotis Papadimitroulas
- Department of Biomedical Engineering, Technological Educational Institute of Athens, 12210, Athens, Greece
| | - Yann Perrot
- UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière, France
| | - Uwe Pietrzyk
- Institut für Neurowissenschaften und Medizin, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany and Fachbereich für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal, Germany
| | - Charlotte Robert
- IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, Orsay 91406, France
| | - Dennis R Schaart
- Delft University of Technology, Faculty of Applied Sciences, Radiation Science and Technology Department, Delft Mekelweg 15, 2629 JB Delft, The Netherlands
| | | | - Irène Buvat
- IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, 91406 Orsay, France and CEA/DSV/I2BM/SHFJ, 91400 Orsay, France
| |
Collapse
|
45
|
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
|
46
|
Henzen D, Manser P, Frei D, Volken W, Neuenschwander H, Born EJ, Joosten A, Lössl K, Aebersold DM, Chatelain C, Stampanoni MFM, Fix MK. Beamlet based direct aperture optimization for MERT using a photon MLC. Med Phys 2014; 41:121711. [DOI: 10.1118/1.4901638] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
|
47
|
Lacornerie T, Lisbona A, Mirabel X, Lartigau E, Reynaert N. GTV-based prescription in SBRT for lung lesions using advanced dose calculation algorithms. Radiat Oncol 2014; 9:223. [PMID: 25319444 PMCID: PMC4205279 DOI: 10.1186/s13014-014-0223-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 09/29/2014] [Indexed: 12/31/2022] Open
Abstract
Background The aim of current study was to investigate the way dose is prescribed to lung lesions during SBRT using advanced dose calculation algorithms that take into account electron transport (type B algorithms). As type A algorithms do not take into account secondary electron transport, they overestimate the dose to lung lesions. Type B algorithms are more accurate but still no consensus is reached regarding dose prescription. The positive clinical results obtained using type A algorithms should be used as a starting point. Methods In current work a dose-calculation experiment is performed, presenting different prescription methods. Three cases with three different sizes of peripheral lung lesions were planned using three different treatment platforms. For each individual case 60 Gy to the PTV was prescribed using a type A algorithm and the dose distribution was recalculated using a type B algorithm in order to evaluate the impact of the secondary electron transport. Secondly, for each case a type B algorithm was used to prescribe 48 Gy to the PTV, and the resulting doses to the GTV were analyzed. Finally, prescriptions based on specific GTV dose volumes were evaluated. Results When using a type A algorithm to prescribe the same dose to the PTV, the differences regarding median GTV doses among platforms and cases were always less than 10% of the prescription dose. The prescription to the PTV based on type B algorithms, leads to a more important variability of the median GTV dose among cases and among platforms, (respectively 24%, and 28%). However, when 54 Gy was prescribed as median GTV dose, using a type B algorithm, the variability observed was minimal. Conclusion Normalizing the prescription dose to the median GTV dose for lung lesions avoids variability among different cases and treatment platforms of SBRT when type B algorithms are used to calculate the dose. The combination of using a type A algorithm to optimize a homogeneous dose in the PTV and using a type B algorithm to prescribe the median GTV dose provides a very robust method for treating lung lesions. Electronic supplementary material The online version of this article (doi:10.1186/s13014-014-0223-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | - Albert Lisbona
- Service de Physique Médicale, Institut de Cancérologie de l'Ouest, Nantes, France.
| | - Xavier Mirabel
- Département Universitaire de Radiothérapie, Centre Oscar Lambret, Lille, France.
| | - Eric Lartigau
- Département Universitaire de Radiothérapie, Centre Oscar Lambret, Lille, France.
| | - Nick Reynaert
- Service de Physique Médicale, Centre Oscar Lambret, Lille, France.
| |
Collapse
|
48
|
Ureba A, Salguero FJ, Barbeiro AR, Jimenez-Ortega E, Baeza JA, Miras H, Linares R, Perucha M, Leal A. MCTP system model based on linear programming optimization of apertures obtained from sequencing patient image data maps. Med Phys 2014; 41:081719. [PMID: 25086529 DOI: 10.1118/1.4890602] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE The authors present a hybrid direct multileaf collimator (MLC) aperture optimization model exclusively based on sequencing of patient imaging data to be implemented on a Monte Carlo treatment planning system (MC-TPS) to allow the explicit radiation transport simulation of advanced radiotherapy treatments with optimal results in efficient times for clinical practice. METHODS The planning system (called CARMEN) is a full MC-TPS, controlled through aMATLAB interface, which is based on the sequencing of a novel map, called "biophysical" map, which is generated from enhanced image data of patients to achieve a set of segments actually deliverable. In order to reduce the required computation time, the conventional fluence map has been replaced by the biophysical map which is sequenced to provide direct apertures that will later be weighted by means of an optimization algorithm based on linear programming. A ray-casting algorithm throughout the patient CT assembles information about the found structures, the mass thickness crossed, as well as PET values. Data are recorded to generate a biophysical map for each gantry angle. These maps are the input files for a home-made sequencer developed to take into account the interactions of photons and electrons with the MLC. For each linac (Axesse of Elekta and Primus of Siemens) and energy beam studied (6, 9, 12, 15 MeV and 6 MV), phase space files were simulated with the EGSnrc/BEAMnrc code. The dose calculation in patient was carried out with the BEAMDOSE code. This code is a modified version of EGSnrc/DOSXYZnrc able to calculate the beamlet dose in order to combine them with different weights during the optimization process. RESULTS Three complex radiotherapy treatments were selected to check the reliability of CARMEN in situations where the MC calculation can offer an added value: A head-and-neck case (Case I) with three targets delineated on PET/CT images and a demanding dose-escalation; a partial breast irradiation case (Case II) solved with photon and electron modulated beams (IMRT + MERT); and a prostatic bed case (Case III) with a pronounced concave-shaped PTV by using volumetric modulated arc therapy. In the three cases, the required target prescription doses and constraints on organs at risk were fulfilled in a short enough time to allow routine clinical implementation. The quality assurance protocol followed to check CARMEN system showed a high agreement with the experimental measurements. CONCLUSIONS A Monte Carlo treatment planning model exclusively based on maps performed from patient imaging data has been presented. The sequencing of these maps allows obtaining deliverable apertures which are weighted for modulation under a linear programming formulation. The model is able to solve complex radiotherapy treatments with high accuracy in an efficient computation time.
Collapse
Affiliation(s)
- A Ureba
- Dpto. Fisiología Médica y Biofísica. Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla, Spain
| | - F J Salguero
- Nederlands Kanker Instituut, Antoni van Leeuwenhoek Ziekenhuis, 1066 CX Ámsterdam, The Nederlands
| | - A R Barbeiro
- Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla, Spain
| | - E Jimenez-Ortega
- Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla, Spain
| | - J A Baeza
- Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla, Spain
| | - H Miras
- Servicio de Radiofísica, Hospital Universitario Virgen Macarena, E-41009 Sevilla, Spain
| | - R Linares
- Servicio de Radiofísica, Hospital Infanta Luisa, E-41010 Sevilla, Spain
| | - M Perucha
- Servicio de Radiofísica, Hospital Infanta Luisa, E-41010 Sevilla, Spain
| | - A Leal
- Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla, Spain
| |
Collapse
|
49
|
Belosi MF, Rodriguez M, Fogliata A, Cozzi L, Sempau J, Clivio A, Nicolini G, Vanetti E, Krauss H, Khamphan C, Fenoglietto P, Puxeu J, Fedele D, Mancosu P, Brualla L. Monte Carlo simulation of TrueBeam flattening-filter-free beams using Varian phase-space files: Comparison with experimental data. Med Phys 2014; 41:051707. [DOI: 10.1118/1.4871041] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
50
|
Ojala J, Hyödynmaa S, Barańczyk R, Góra E, Waligórski M. Performance of two commercial electron beam algorithms over regions close to the lung–mediastinum interface, against Monte Carlo simulation and point dosimetry in virtual and anthropomorphic phantoms. Phys Med 2014; 30:147-54. [DOI: 10.1016/j.ejmp.2013.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 03/06/2013] [Accepted: 04/25/2013] [Indexed: 11/25/2022] Open
|