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Huang Z, Tian L, Janssens G, Smeets J, Xie Y, Kevin Teo BK, Nilsson R, Traneus E, Parodi K, Pinto M. An experimental validation of a filtering approach for prompt gamma prediction in a research proton treatment planning system. Phys Med Biol 2024; 69:155025. [PMID: 38981589 DOI: 10.1088/1361-6560/ad6116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 07/09/2024] [Indexed: 07/11/2024]
Abstract
Objective.Prompt gamma (PG) radiation generated from nuclear reactions between protons and tissue nuclei can be employed for range verification in proton therapy. A typical clinical workflow for PG range verification compares the detected PG profile with a predicted one. Recently, a novel analytical PG prediction algorithm based on the so-called filtering formalism has been proposed and implemented in a research version of RayStation (RaySearch Laboratories AB), which is a widely adopted treatment planning system. This work validates the performance of the filtering PG prediction approach.Approach.The said algorithm is validated against experimental data and benchmarked with another well-established PG prediction algorithm implemented in a MATLAB-based software REGGUI. Furthermore, a new workflow based on several PG profile quality criteria and analytical methods is proposed for data selection. The workflow also calculates sensitivity and specificity information, which can help practitioners to decide on irradiation course interruption during treatment and monitor spot selection at the treatment planning stage. With the proposed workflow, the comparison can be performed on a limited number of selected high-quality irradiation spots without neighbouring-spot aggregation.Main results.The mean shifts between the experimental data and the predicted PG detection (PGD) profiles (ΔPGD) by the two algorithms are estimated to be1.5±2.1mm and-0.6±2.2mm for the filtering and REGGUI prediction methods, respectively. The ΔPGD difference between two algorithms is observed to be consistent with the beam model difference within uncertainty. However, the filtering approach requires a much shorter computation time compared to the REGGUI approach.Significance.The novel filtering approach is successfully validated against experimental data and another widely used PG prediction algorithm. The workflow designed in this work selects spots with high-quality PGD shift calculation results, and performs sensitivity and specificity analyses to assist clinical decisions.
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Affiliation(s)
- Ze Huang
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Liheng Tian
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | | | - Yunhe Xie
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, United States of America
| | - Boon-Keng Kevin Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States of America
| | | | | | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marco Pinto
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
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Park H, Paganetti H, Schuemann J, Jia X, Min CH. Monte Carlo methods for device simulations in radiation therapy. Phys Med Biol 2021; 66:10.1088/1361-6560/ac1d1f. [PMID: 34384063 PMCID: PMC8996747 DOI: 10.1088/1361-6560/ac1d1f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/12/2021] [Indexed: 11/12/2022]
Abstract
Monte Carlo (MC) simulations play an important role in radiotherapy, especially as a method to evaluate physical properties that are either impossible or difficult to measure. For example, MC simulations (MCSs) are used to aid in the design of radiotherapy devices or to understand their properties. The aim of this article is to review the MC method for device simulations in radiation therapy. After a brief history of the MC method and popular codes in medical physics, we review applications of the MC method to model treatment heads for neutral and charged particle radiation therapy as well as specific in-room devices for imaging and therapy purposes. We conclude by discussing the impact that MCSs had in this field and the role of MC in future device design.
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Affiliation(s)
- Hyojun Park
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Xun Jia
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75235, United States of America
| | - Chul Hee Min
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
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Tian L, Huang Z, Janssens G, Landry G, Dedes G, Kamp F, Belka C, Pinto M, Parodi K. Accounting for prompt gamma emission and detection for range verification in proton therapy treatment planning. Phys Med Biol 2021; 66:055005. [PMID: 33171445 DOI: 10.1088/1361-6560/abc939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Prompt gamma (PG) imaging is widely investigated as one of the most promising methods for proton range verification in proton therapy. The performance of this technique is affected by several factors like tissue heterogeneity, number of protons in the considered pencil beam and the detection device. Our previous work proposed a new treatment planning concept which boosts the number of protons of a few PG monitoring-friendly pencil beams (PBs), selected on the basis of two proposed indicators quantifying the conformity between the dose and PG at the emission level, above the desired detectability threshold. To further explore this method at the detection level, in this work we investigated the response of a knife-edge slit PG camera which was deployed in the first clinical application of PG to proton therapy monitoring. The REGistration Graphical User Interface (REGGUI) is employed to simulate the PG emission, PG detection as well as the corresponding dose distribution. As the PG signal detected by this kind of PG camera is sensitive to the relative position of the camera and PG signal falloff, we optimized our PB selection method for this camera by introducing a new camera position indicator identifying whether the expected falloff of the PG signal is centered in the field of view of the camera or not. Our camera-adapted PB selection method is investigated using computed tomography (CT) scans at two different treatment time points of a head and neck, and a prostate cancer patient under scenarios considering different statistics level. The results show that a precision of 0.8 mm for PG falloff identification can be achieved when a PB has more than 2 × 108 primary protons. Except for one case due to unpredictable and comparably large anatomical changes, the PG signals of most of the PBs recommended by all our indicators are observed to be reliable for proton range verification with deviations between the inter-fractional shift of proton range (as deduced from the PB dose distribution) and the detected PG signal within 2.0 mm. In contrast, a shift difference up to 9.6 mm has been observed for the rejected PBs. The magnitude of the proton range shift due to the inter-fractional anatomical changes is observed to be up to 23 mm. The proposed indicators are shown to be valuable for identifying and recommending reliable PBs to create new PG monitoring-friendly TPs. Comparison between our PB boosting method and the alternative PB aggregation, which combines the signal of nearby PBs to reach the desired counting statistics, is also discussed.
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Affiliation(s)
- Liheng Tian
- Ludwig-Maximilians-Universität München, Department of Medical Physics, Munich, Germany. These authors have contributed to this work equally
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4
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Chen Q, Zhang J. The impact of x-ray incident angle on indirect fluoroscopy skin dose estimation. Biomed Phys Eng Express 2021; 7:015005. [DOI: 10.1088/2057-1976/abc966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Indirect dosimetry to calculate peak skin dose (PSD) is generally based on reference air kerma or kerma-area-product, with effects of table attenuation, inverse square law and backscatter factor applied. When the incident x-ray beam angle changes, these factors would change as well. The purpose of this study is to identify the impact of incident x-ray beam angle on the accuracy of indirect PSD calculation and develop a correction method. Monte Carlo simulation was conducted to assist analytical equation derivation and to validate the developed analytical method. Direct PSD measurements were performed a Siemens Artis Zee biplane fluoroscopy and a GE OEC C-Arm at different angles to validate the proposed correction method and its independence of fluoroscopy systems. Compared with MC simulated PSD, the derived analytical equation successfully predicts these PSD changes for incident angles of 0, 15, 30 and 40 degrees, with the residual error magnitude of 0.3%–3.1% corresponding to different SSDs. The agreement between calculated PSD also agrees well with direct measurement.
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Chen Q, Carlton D, Howard TJ, Izumi T, Rong Y. Technical Note: Vendor miscalibration of preclinical orthovoltage irradiator identified through independent output check. Med Phys 2020; 48:881-889. [PMID: 33283893 DOI: 10.1002/mp.14642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Accurate radiation dosimetry in radiobiological experiments is crucial for preclinical research in advancement of cancer treatment. Vendors of cell irradiators often perform calibration for end-users. However, calibration accuracy remains unclear due to missing detailed information on calibration equipment and procedures. In this study, we report our findings of a vender miscalibration of the radiation output and our investigation on the root cause of the discrepancy. METHODS Independent calibration verification for a commercial preclinical orthovoltage irradiator was conducted. Initially, in the absence of ionization chambers calibrated at kV energy, radiochromic films (EBT3) was first calibrated at MV energy. Energy correction factors from literature were used to create an in-house kV dosimetry system. The miscalibration identified with the in-house kV EBT3 dosimetry was later confirmed by ADCL calibrated ionization chambers (Exradin A1SL and PTW 30013) at kV energy. Ionization chambers were suspended in-air following TG-61 recommendation for output calibration. To investigate the root cause of the miscalibration, additional measurements were performed with ionization chambers placed on the shelf. A validated Monte Carlo simulation code was also used to investigate the impact of placing the ionization chamber on the shelf instead of suspending it in air during the vendor-performed calibration process. RESULTS Up to a 6% dosimetry error was observed when comparing the vendor calibrated output of the preclinical irradiator with our independent calibration check. Further investigation showed incorrect setups in the vendor's calibration procedure which may result in dose errors up to 11% from the backscatter of the shelf board during calibration, and up to 5% from omitting temperature and pressure corrections to ionization chamber readings. CONCLUSION Our study revealed large dose calibration errors caused by incorrect setup and the omission of temperature/pressure correction in the vendor's calibration procedure. The findings also highlighted the importance of performing an independent check of the dose calibration for preclinical kV irradiators. More absolute dosimetry training is needed for both vendors and end users for establishing accurate absolute dosimetry.
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Affiliation(s)
- Quan Chen
- Department of Radiation Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Drew Carlton
- Department of Radiation Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Thaddeus J Howard
- Department of Radiation Medicine, University of Kentucky, Lexington, KY, 40536, USA.,Department of Radiation Oncology, Texas Oncology, Dallas, TX, 75231, USA
| | - Tadahide Izumi
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, 40536, USA
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
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Verbeek N, Wulff J, Bäumer C, Smyczek S, Timmermann B, Brualla L. Single pencil beam benchmark of a module for Monte Carlo simulation of proton transport in the PENELOPE code. Med Phys 2020; 48:456-476. [PMID: 33217026 DOI: 10.1002/mp.14598] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND AND PURPOSE PENH is a recently coded module for simulation of proton transport in conjunction with the Monte Carlo code PENELOPE. PENELOPE applies class II simulation to all type of interactions, in particular, to elastic collisions. PENH uses calculated differential cross sections for proton elastic collisions that include electron screening effects as well as nuclear structure effects. Proton-induced nuclear reactions are simulated from information in the ENDF-6 database or from alternative nuclear databases in ENDF format. The purpose of this work is to benchmark this module by simulating absorbed dose distributions from a single finite spot size proton pencil beam in water. MATERIALS AND METHODS Monte Carlo simulations with PENH are compared with simulation results from TOPAS Monte Carlo (v3.1p2) and RayStation Monte Carlo (v6). Different beam models are examined in terms of mean energy and energy spread to match the measured profiles. The phase-space file is derived from experimental measurements. Simulated absorbed dose distributions are compared to experimental data obtained with the ionization chamber array MatriXX 2D detector (IBA Dosimetry) in a water tank. The experiments were conducted with a clinical IBA pencil beam scanning dedicated nozzle. In all simulations a Fermi-Eyges phase-space representation of a single finite spot size proton pencil beam is used. RESULTS In general, there is a good agreement between simulated results and experimental data up to a distance of 3 cm from the central axis. In the core region (region where the dose is more than 10% of the maximum dose) PENH shows, overall, the smallest deviations from experimental data, with the largest radial rms (root mean square) smaller than 0.2. The results achieved by TOPAS and RayStation in that region are very close to those of PENH. For the halo region, that is the area of the dose distribution outside the core region reaching down to 0.01% of the maximum intensity, the largest rms achieved by TOPAS is always smaller than 0.5, yielding better results than the rest of the codes. CONCLUSION The physics modeling of the PENELOPE/PENH code yields results consistent with measurements in the dose range relevant for proton therapy. The discrepancies between PENH appearing at distances larger than 3 cm from the central-beam axis are accountable to the lack of neutron simulation in this code. In contradistinction, TOPAS has a better agreement with experimental data at large distances from the central-beam axis because of the simulation of neutrons.
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Affiliation(s)
- Nico Verbeek
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
| | - Jörg Wulff
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Technische Universität Dortmund, Otto-Hahn-Str. 4a, Dortmund, 44227, Germany
| | - Sabrina Smyczek
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Faculty of Physics, Heinrich Heine University Düsseldorf HHU, Düsseldorf, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany.,Radiation Oncology and Imaging, German Cancer Consortium DKTK, Heidelberg, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Lorenzo Brualla
- West German Proton Therapy Centre Essen WPE, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,University Hospital Essen, West German Cancer Center WTZ, Essen, Germany
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Baumann K, Horst F, Zink K, Gomà C. Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high-energy photon and proton beams. Med Phys 2019; 46:4639-4653. [PMID: 31350915 PMCID: PMC6851981 DOI: 10.1002/mp.13737] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 07/01/2019] [Accepted: 07/16/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE The purpose of this work is to analyze whether the Monte Carlo codes penh, fluka, and geant4/topas are suitable to calculate absorbed doses andf Q / f Q 0 ratios in therapeutic high-energy photon and proton beams. METHODS We used penh, fluka, geant4/topas, and egsnrc to calculate the absorbed dose to water in a reference water cavity and the absorbed dose to air in two air cavities representative of a plane-parallel and a cylindrical ionization chamber in a 1.25 MeV photon beam and a 150 MeV proton beam - egsnrc was only used for the photon beam calculations. The physics and transport settings in each code were adjusted to simulate the particle transport as detailed as reasonably possible. From these absorbed doses, f Q 0 factors, f Q factors, andf Q / f Q 0 ratios (which are the basis of Monte Carlo calculated beam quality correction factors k Q , Q 0 ) were calculated and compared between the codes. Additionally, we calculated the spectra of primary particles and secondary electrons in the reference water cavity, as well as the integrated depth-dose curve of 150 MeV protons in water. RESULTS The absorbed doses agreed within 1.4% or better between the individual codes for both the photon and proton simulations. The f Q 0 and f Q factors agreed within 0.5% or better for the individual codes for both beam qualities. The resultingf Q / f Q 0 ratios for 150 MeV protons agreed within 0.7% or better. For the 1.25 MeV photon beam, the spectra of photons and secondary electrons agreed almost perfectly. For the 150 MeV proton simulation, we observed differences in the spectra of secondary protons whereas the spectra of primary protons and low-energy delta electrons also agreed almost perfectly. The first 2 mm of the entrance channel of the 150 MeV proton Bragg curve agreed almost perfectly while for greater depths, the differences in the integrated dose were up to 1.5%. CONCLUSION penh, fluka, and geant4/topas are capable of calculating beam quality correction factors in proton beams. The differences in the f Q 0 and f Q factors between the codes are 0.5% at maximum. The differences in thef Q / f Q 0 ratios are 0.7% at maximum.
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Affiliation(s)
- Kilian‐Simon Baumann
- Department of Radiotherapy and RadiooncologyUniversity Medical Center Giessen‐MarburgMarburgGermany
- Institute of Medical Physics and Radiation ProtectionUniversity of Applied SciencesGiessenGermany
| | - Felix Horst
- Institute of Medical Physics and Radiation ProtectionUniversity of Applied SciencesGiessenGermany
- GSI Helmholtzzentrum für SchwerionenforschungDarmstadtGermany
| | - Klemens Zink
- Department of Radiotherapy and RadiooncologyUniversity Medical Center Giessen‐MarburgMarburgGermany
- Institute of Medical Physics and Radiation ProtectionUniversity of Applied SciencesGiessenGermany
- Frankfurt Institute for Advanced Studies (FIAS)FrankfurtGermany
| | - Carles Gomà
- Department of Oncology, Laboratory of Experimental RadiotherapyKU LeuvenLeuvenBelgium
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Gomà C, Sterpin E. Monte Carlo calculation of beam quality correction factors in proton beams using PENH. ACTA ACUST UNITED AC 2019; 64:185009. [DOI: 10.1088/1361-6560/ab3b94] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chen Q, Molloy J, Izumi T, Sterpin E. Impact of backscatter material thickness on the depth dose of orthovoltage irradiators for radiobiology research. Phys Med Biol 2019; 64:055001. [PMID: 30673636 DOI: 10.1088/1361-6560/ab0120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The orthovoltage x-ray energy frequently used in radiation research is prone to dosimetry errors due to insufficient backscatter conditions. In many radiobiology studies, especially for cell irradiations, precise dose calculation algorithms such as Convolution-Superposition or Monte Carlo are impractical and as such, less accurate hand calculation methods are used for dose estimation. These dose estimation methods typically assume full backscatter conditions. The purpose of this study is to demonstrate the magnitude of the dose error that results from insufficient backscatter, and to provide lookup tables to account this issue. The beam spectra of several widely used commercial systems (XRAD-225, XRAD-320, SARRP) were used in Monte Carlo (MC) simulations on a series of phantom setups to investigate the impact of varying backscatter conditions on dosimetry. The depth dose curves for different field sizes, water phantom thicknesses and beam qualities were generated. In addition, depth dependent backscatter factors for different field sizes and different beam qualities were calculated. It is demonstrated that as much as a 50% dose difference exists for different backscatter conditions at the beam qualities studied. The choice of cell dish size as well as other changes in the experiment setup can have more than 10% impact on the dose. The impact of backscatter is reduced with a decrease in field size. Further, the thickness needed to provide full backscatter can be approximated as being equal to the field size. It is imperative to ensure full backscatter conditions during system and dosimeter calibration, or to use the look-up table provided in this study.
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Affiliation(s)
- Quan Chen
- Department of Radiation Medicine, The University of Kentucky, Lexington, KY 40536, United States of America. Author to whom any correspondence should be addressed. Radiation Medicine, University of Kentucky, Markey Cancer Center, Rm CC063, 800 Rose St., Lexington, KY 40536-0293, United States of America
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10
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Gomà C, Safai S, Vörös S. Reference dosimetry of proton pencil beams based on dose-area product: a proof of concept. Phys Med Biol 2017; 62:4991-5005. [DOI: 10.1088/1361-6560/aa7008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Experimental assessment of proton dose calculation accuracy in inhomogeneous media. Phys Med 2017; 38:10-15. [PMID: 28610689 DOI: 10.1016/j.ejmp.2017.04.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 04/07/2017] [Accepted: 04/19/2017] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Proton therapy with Pencil Beam Scanning (PBS) has the potential to improve radiotherapy treatments. Unfortunately, its promises are jeopardized by the sensitivity of the dose distributions to uncertainties, including dose calculation accuracy in inhomogeneous media. Monte Carlo dose engines (MC) are expected to handle heterogeneities better than analytical algorithms like the pencil-beam convolution algorithm (PBA). In this study, an experimental phantom has been devised to maximize the effect of heterogeneities and to quantify the capability of several dose engines (MC and PBA) to handle these. METHODS An inhomogeneous phantom made of water surrounding a long insert of bone tissue substitute (1×10×10 cm3) was irradiated with a mono-energetic PBS field (10×10 cm2). A 2D ion chamber array (MatriXX, IBA Dosimetry GmbH) lied right behind the bone. The beam energy was such that the expected range of the protons exceeded the detector position in water and did not attain it in bone. The measurement was compared to the following engines: Geant4.9.5, PENH, MCsquare, as well as the MC and PBA algorithms of RayStation (RaySearch Laboratories AB). RESULTS For a γ-index criteria of 2%/2mm, the passing rates are 93.8% for Geant4.9.5, 97.4% for PENH, 93.4% for MCsquare, 95.9% for RayStation MC, and 44.7% for PBA. The differences in γ-index passing rates between MC and RayStation PBA calculations can exceed 50%. CONCLUSION The performance of dose calculation algorithms in highly inhomogeneous media was evaluated in a dedicated experiment. MC dose engines performed overall satisfactorily while large deviations were observed with PBA as expected.
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Xie Y, Bentefour EH, Janssens G, Smeets J, Vander Stappen F, Hotoiu L, Yin L, Dolney D, Avery S, O'Grady F, Prieels D, McDonough J, Solberg TD, Lustig RA, Lin A, Teo BKK. Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy. Int J Radiat Oncol Biol Phys 2017; 99:210-218. [PMID: 28816148 DOI: 10.1016/j.ijrobp.2017.04.027] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 03/22/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. METHODS AND MATERIALS A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. RESULTS In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. CONCLUSIONS This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties.
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Affiliation(s)
- Yunhe Xie
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Guillaume Janssens
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - Julien Smeets
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | | | - Lucian Hotoiu
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - Lingshu Yin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Derek Dolney
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen Avery
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Fionnbarr O'Grady
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Damien Prieels
- Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium
| | - James McDonough
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Timothy D Solberg
- Department of Radiation Oncology, University of California, San Francisco, California
| | - Robert A Lustig
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alexander Lin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Boon-Keng K Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
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Souris K, Lee JA, Sterpin E. Fast multipurpose Monte Carlo simulation for proton therapy using multi- and many-core CPU architectures. Med Phys 2016; 43:1700. [PMID: 27036568 DOI: 10.1118/1.4943377] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Accuracy in proton therapy treatment planning can be improved using Monte Carlo (MC) simulations. However the long computation time of such methods hinders their use in clinical routine. This work aims to develop a fast multipurpose Monte Carlo simulation tool for proton therapy using massively parallel central processing unit (CPU) architectures. METHODS A new Monte Carlo, called MCsquare (many-core Monte Carlo), has been designed and optimized for the last generation of Intel Xeon processors and Intel Xeon Phi coprocessors. These massively parallel architectures offer the flexibility and the computational power suitable to MC methods. The class-II condensed history algorithm of MCsquare provides a fast and yet accurate method of simulating heavy charged particles such as protons, deuterons, and alphas inside voxelized geometries. Hard ionizations, with energy losses above a user-specified threshold, are simulated individually while soft events are regrouped in a multiple scattering theory. Elastic and inelastic nuclear interactions are sampled from ICRU 63 differential cross sections, thereby allowing for the computation of prompt gamma emission profiles. MCsquare has been benchmarked with the gate/geant4 Monte Carlo application for homogeneous and heterogeneous geometries. RESULTS Comparisons with gate/geant4 for various geometries show deviations within 2%-1 mm. In spite of the limited memory bandwidth of the coprocessor simulation time is below 25 s for 10(7) primary 200 MeV protons in average soft tissues using all Xeon Phi and CPU resources embedded in a single desktop unit. CONCLUSIONS MCsquare exploits the flexibility of CPU architectures to provide a multipurpose MC simulation tool. Optimized code enables the use of accurate MC calculation within a reasonable computation time, adequate for clinical practice. MCsquare also simulates prompt gamma emission and can thus be used also for in vivo range verification.
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Affiliation(s)
- Kevin Souris
- Center for Molecular Imaging and Experimental Radiotherapy, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and ICTEAM Institute, Université catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - John Aldo Lee
- Center for Molecular Imaging and Experimental Radiotherapy, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and ICTEAM Institute, Université catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - Edmond Sterpin
- Center for Molecular Imaging and Experimental Radiotherapy, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and Department of Oncology, Katholieke Universiteit Leuven, O&N I Herestraat 49, 3000 Leuven, Belgium
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VoxelMages: a general-purpose graphical interface for designing geometries and processing DICOM images for PENELOPE. Appl Radiat Isot 2016; 118:251-257. [DOI: 10.1016/j.apradiso.2016.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/01/2016] [Accepted: 09/19/2016] [Indexed: 11/20/2022]
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15
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Gomà C, Andreo P, Sempau J. Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers. Phys Med Biol 2016; 61:2389-406. [DOI: 10.1088/0031-9155/61/6/2389] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Janssens G, Smeets J, Vander Stappen F, Prieels D, Clementel E, Hotoiu EL, Sterpin E. Sensitivity study of prompt gamma imaging of scanned beam proton therapy in heterogeneous anatomies. Radiother Oncol 2015; 118:562-7. [PMID: 26627703 DOI: 10.1016/j.radonc.2015.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 10/27/2015] [Accepted: 11/01/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND PURPOSE To investigate the use of a fast analytical prediction algorithm in the evaluation of the accuracy in Bragg peak position estimation using prompt gamma imaging in realistic anatomies. MATERIAL AND METHODS Brain, nasal cavity and lung spot scanning treatments were planned on an anthropomorphic phantom. Plan delivery in a clinical proton therapy facility was monitored using a prompt gamma camera. A pencil-beam algorithm was developed to simulate prompt gamma acquisition. For each spot, the sensitivity to setup and CT conversion errors was evaluated based on error scenarios. RESULTS Good agreement was found between simulations and measurements (average shift of 0.4mm on whole-layer profiles). The spots with greatest sensitivity to setup or CT conversion errors could be identified. The comparison between expected and estimated shifts showed that the errors in shift estimation due to heterogeneities were in average lower than 1mm in all cases except the lung. In the lung case, only 40% of the spots showed accuracy better than 2mm. CONCLUSIONS The analytical prediction algorithm was successfully used to simulate prompt gamma acquisitions of scanned treatment plans. The accuracy in Bragg peak position estimation was generally sub-millimeter in heterogeneous anatomies, except in lung tissues.
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Affiliation(s)
| | | | | | | | - Enrico Clementel
- Université catholique de Louvain, iMagX Project, ICTEAM Institute, Louvain-la-Neuve, Belgium
| | - Eugen-Lucian Hotoiu
- Université catholique de Louvain, iMagX Project, ICTEAM Institute, Louvain-la-Neuve, Belgium
| | - Edmond Sterpin
- Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Expérimentale et Clinique, Brussels, Belgium.
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Kraan AC. Range Verification Methods in Particle Therapy: Underlying Physics and Monte Carlo Modeling. Front Oncol 2015; 5:150. [PMID: 26217586 PMCID: PMC4493660 DOI: 10.3389/fonc.2015.00150] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/17/2015] [Indexed: 01/27/2023] Open
Abstract
Hadron therapy allows for highly conformal dose distributions and better sparing of organs-at-risk, thanks to the characteristic dose deposition as function of depth. However, the quality of hadron therapy treatments is closely connected with the ability to predict and achieve a given beam range in the patient. Currently, uncertainties in particle range lead to the employment of safety margins, at the expense of treatment quality. Much research in particle therapy is therefore aimed at developing methods to verify the particle range in patients. Non-invasive in vivo monitoring of the particle range can be performed by detecting secondary radiation, emitted from the patient as a result of nuclear interactions of charged hadrons with tissue, including β (+) emitters, prompt photons, and charged fragments. The correctness of the dose delivery can be verified by comparing measured and pre-calculated distributions of the secondary particles. The reliability of Monte Carlo (MC) predictions is a key issue. Correctly modeling the production of secondaries is a non-trivial task, because it involves nuclear physics interactions at energies, where no rigorous theories exist to describe them. The goal of this review is to provide a comprehensive overview of various aspects in modeling the physics processes for range verification with secondary particles produced in proton, carbon, and heavier ion irradiation. We discuss electromagnetic and nuclear interactions of charged hadrons in matter, which is followed by a summary of some widely used MC codes in hadron therapy. Then, we describe selected examples of how these codes have been validated and used in three range verification techniques: PET, prompt gamma, and charged particle detection. We include research studies and clinically applied methods. For each of the techniques, we point out advantages and disadvantages, as well as clinical challenges still to be addressed, focusing on MC simulation aspects.
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Affiliation(s)
- Aafke Christine Kraan
- Department of Physics, National Institute for Nuclear Physics (INFN), University of Pisa, Pisa, Italy
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Sterpin E, Janssens G, Smeets J, Stappen FV, Prieels D, Priegnitz M, Perali I, Vynckier S. Analytical computation of prompt gamma ray emission and detection for proton range verification. Phys Med Biol 2015; 60:4915-46. [DOI: 10.1088/0031-9155/60/12/4915] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Priegnitz M, Helmbrecht S, Janssens G, Perali I, Smeets J, Vander Stappen F, Sterpin E, Fiedler F. Measurement of prompt gamma profiles in inhomogeneous targets with a knife-edge slit camera during proton irradiation. Phys Med Biol 2015; 60:4849-71. [DOI: 10.1088/0031-9155/60/12/4849] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Roellinghoff F, Benilov A, Dauvergne D, Dedes G, Freud N, Janssens G, Krimmer J, Létang JM, Pinto M, Prieels D, Ray C, Smeets J, Stichelbaut F, Testa E. Real-time proton beam range monitoring by means of prompt-gamma detection with a collimated camera. Phys Med Biol 2014; 59:1327-38. [DOI: 10.1088/0031-9155/59/5/1327] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Sterpin E, Sorriaux J, Souris K, Vynckier S, Bouchard H. A Fano cavity test for Monte Carlo proton transport algorithms. Med Phys 2013; 41:011706. [DOI: 10.1118/1.4835475] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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