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Amstutz F, Krcek R, Bachtiary B, Weber DC, Lomax AJ, Unkelbach J, Zhang Y. Treatment planning comparison for head and neck cancer between photon, proton, and combined proton-photon therapy - From a fixed beam line to an arc. Radiother Oncol 2024; 190:109973. [PMID: 37913953 DOI: 10.1016/j.radonc.2023.109973] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 09/25/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
BACKGROUND AND PURPOSE This study investigates whether combined proton-photon therapy (CPPT) improves treatment plan quality compared to single-modality intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT) for head and neck cancer (HNC) patients. Different proton beam arrangements for CPPT and IMPT are compared, which could be of specific interest concerning potential future upright-positioned treatments. Furthermore, it is evaluated if CPPT benefits remain under inter-fractional anatomical changes for HNC treatments. MATERIAL AND METHODS Five HNC patients with a planning CT and multiple (4-7) repeated CTs were studied. CPPT with simultaneously optimized photon and proton fluence, single-modality IMPT, and IMRT treatment plans were optimized on the planning CT and then recalculated and reoptimized on each repeated CT. For CPPT and IMPT, plans with different degrees of freedom for the proton beams were optimized. Fixed horizontal proton beam line (FHB), gantry-like, and arc-like plans were compared. RESULTS The target coverage for CPPT without adaptation is insufficient (average V95%=88.4 %), while adapted plans can recover the initial treatment plan quality for target (average V95%=95.5 %) and organs-at-risk. CPPT with increased proton beam flexibility increases plan quality and reduces normal tissue complication probability of Xerostomia and Dysphagia. On average, Xerostomia NTCP reductions compared to IMRT are -2.7 %/-3.4 %/-5.0 % for CPPT FHB/CPPT Gantry/CPPT Arc. The differences for IMPT FHB/IMPT Gantry/IMPT Arc are + 0.8 %/-0.9 %/-4.3 %. CONCLUSION CPPT for HNC needs adaptive treatments. Increasing proton beam flexibility in CPPT, either by using a gantry or an upright-positioned patient, improves treatment plan quality. However, the photon component is substantially reduced, therefore, the balance between improved plan quality and costs must be further determined.
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Affiliation(s)
- Florian Amstutz
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Physics, ETH Zurich, Switzerland
| | - Reinhardt Krcek
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | | | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Radiation Oncology, University Hospital Zurich, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Antony J Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Physics, ETH Zurich, Switzerland
| | - Jan Unkelbach
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| | - Ye Zhang
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.
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Wu X, Amstutz F, Weber DC, Unkelbach J, Lomax AJ, Zhang Y. Patient-specific quality assurance for deformable IMRT/IMPT dose accumulation: Proposition and validation of energy conservation based validation criterion. Med Phys 2023; 50:7130-7138. [PMID: 37345380 DOI: 10.1002/mp.16564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/17/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Deformable image registration (DIR)-based dose accumulation (DDA) is regularly used in adaptive radiotherapy research. However, the applicability and reliability of DDA for direct clinical usage are still being debated. One primary concern is the validity of DDA, particularly for scenarios with substantial anatomical changes, for which energy-conservation problems were observed in conceptual studies. PURPOSE We present and validate an energy-conservation (EC)-based DDA validation workflow and further investigate its usefulness for actual patient data, specifically for lung cancer cases. METHODS For five non-small cell lung cancer (NSCLC) patients, DDA based on five selective DIR methods were calculated for five different treatment plans, which include one intensity-modulated photon therapy (IMRT), two intensity-modulated proton therapy (IMPT), and two combined proton-photon therapy (CPPT) plans. All plans were optimized on the planning CT (planCT) acquired in deep inspiration breath-hold (DIBH) and were re-optimized on the repeated DIBH CTs of three later fractions. The resulting fractional doses were warped back to the planCT using each DIR. An EC-based validation of the accumulation process was implemented and applied to all DDA results. Correlations between relative organ mass/volume variations and the extent of EC violation were then studied using Bayesian linear regression (BLR). RESULTS For most OARs, EC violation within 10% is observed. However, for the PTVs and GTVs with substantial regression, severe overestimation of the fractional energy was found regardless of treatment type and applied DIR method. BLR results show that EC violation is linearly correlated to the relative mass variation (R^2 > 0.95) and volume variation (R^2 > 0.60). CONCLUSION DDA results should be used with caution in regions with high mass/volume variation for intensity-based DIRs. EC-based validation is a useful approach to provide patient-specific quality assurance of the validity of DDA in radiotherapy.
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Affiliation(s)
- Xin Wu
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
- Department of Information Technology & Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Florian Amstutz
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
- Department of Radiation Oncology, University Hospital Zurich, Zurich, Switzerland
- Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Jan Unkelbach
- Department of Radiation Oncology, University Hospital Zurich, Zurich, Switzerland
| | - Antony J Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Ye Zhang
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
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Li W, Zhang W, Lin Y, Chen RC, Gao H. Fraction optimization for hybrid proton-photon treatment planning. Med Phys 2023. [PMID: 36786202 DOI: 10.1002/mp.16297] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/28/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND Hybrid proton-photon radiotherapy (RT) can provide better plan quality than proton or photon only RT, in terms of robustness of target coverage and sparing of organs-at-risk (OAR). PURPOSE This work develops a hybrid treatment planning method that can optimize the number of proton and photon fractions as well as proton and photon plan variables, so that the hybrid plans can be clinically delivered day-to-day using either proton or photon machine. METHODS In the new hybrid treatment planning method, the total dose distribution (sum of proton dose and photon dose) is optimized for robust target coverage and optimal OAR sparing, by jointly optimizing proton spots and photon fluences, while the target dose uniformity is also enforced individually on both proton dose and photon dose, so that the hybrid plans can be separately and robustly delivered on proton or photon machine. To ensure the target dose uniformity for proton and photon plans, the number of proton and photon fractions is explicitly modeled and optimized, so that the target dose for proton and photon dose components is constrained to be a constant fraction of the total prescription dose while the plan quality based on total dose is optimized. The feasibility of hybrid planning using the proposed method is validated with representative clinical cases including abdomen, lung, head-and-neck (HN), and brain. RESULTS For all cases, hybrid plans provided better overall plan quality and OAR sparing than proton-only or photon-only plans, better target dose uniformity and robustness than proton-only plans, quantified by treatment planning objectives and dosimetric parameters. Moreover, for HN and brain cases, hybrid plans also had better target coverage than photon-only plans. CONCLUSIONS We have developed a new hybrid treatment planning method that optimizes number of proton and photon fractions as well as proton spots and photon fluences, for generating hybrid plans that can be separately and robustly delivered on proton or photon machines. Preliminary results have demonstrated that hybrid plans generated by the new method have better plan quality than proton-only or photon-only plans.
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Affiliation(s)
- Wangyao Li
- Department of Radiation Oncology, Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Weijie Zhang
- Department of Radiation Oncology, Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Yuting Lin
- Department of Radiation Oncology, Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Ronald C Chen
- Department of Radiation Oncology, Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Hao Gao
- Department of Radiation Oncology, Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA
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Mueller S, Guyer G, Volken W, Frei D, Torelli N, Aebersold DM, Manser P, Fix MK. Efficiency enhancements of a Monte Carlo beamlet based treatment planning process: implementation and parameter study. Phys Med Biol 2023; 68. [PMID: 36655485 DOI: 10.1088/1361-6560/acb480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023]
Abstract
Objective.The computational effort to perform beamlet calculation, plan optimization and final dose calculation of a treatment planning process (TPP) generating intensity modulated treatment plans is enormous, especially if Monte Carlo (MC) simulations are used for dose calculation. The goal of this work is to improve the computational efficiency of a fully MC based TPP for static and dynamic photon, electron and mixed photon-electron treatment techniques by implementing multiple methods and studying the influence of their parameters.Approach.A framework is implemented calculating MC beamlets efficiently in parallel on each available CPU core. The user can specify the desired statistical uncertainty of the beamlets, a fractional sparse dose threshold to save beamlets in a sparse format and minimal distances to the PTV surface from which 2 × 2 × 2 = 8 (medium) or even 4 × 4 × 4 = 64 (large) voxels are merged. The compromise between final plan quality and computational efficiency of beamlet calculation and optimization is studied for several parameter values to find a reasonable trade-off. For this purpose, four clinical and one academic case are considered with different treatment techniques.Main results.Setting the statistical uncertainty to 5% (photon beamlets) and 15% (electron beamlets), the fractional sparse dose threshold relative to the maximal beamlet dose to 0.1% and minimal distances for medium and large voxels to the PTV to 1 cm and 2 cm, respectively, does not lead to substantial degradation in final plan quality compared to using 2.5% (photon beamlets) and 5% (electron beamlets) statistical uncertainty and no sparse format nor voxel merging. Only OAR sparing is slightly degraded. Furthermore, computation times are reduced by about 58% (photon beamlets), 88% (electron beamlets) and 96% (optimization).Significance.Several methods are implemented improving computational efficiency of beamlet calculation and plan optimization of a fully MC based TPP without substantial degradation in final plan quality.
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Affiliation(s)
- S Mueller
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - G Guyer
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - W Volken
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - D Frei
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - N Torelli
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - D M Aebersold
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - P Manser
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - M K Fix
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
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Bennan ABA, Unkelbach J, Wahl N, Salome P, Bangert M. Joint Optimization of Photon-Carbon Ion Treatments for Glioblastoma. Int J Radiat Oncol Biol Phys 2021; 111:559-572. [PMID: 34058258 DOI: 10.1016/j.ijrobp.2021.05.126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/09/2021] [Accepted: 05/21/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE Carbon ions are radiobiologically more effective than photons and are beneficial for treating radioresistant gross tumor volumes (GTV). However, owing to a reduced fractionation effect, they may be disadvantageous for treating infiltrative tumors, in which healthy tissue inside the clinical target volume (CTV) must be protected through fractionation. This work addresses the question: What is the ideal combined photon-carbon ion fluence distribution for treating infiltrative tumors given a specific fraction allocation between photons and carbon ions? METHODS AND MATERIALS We present a method to simultaneously optimize sequentially delivered intensity modulated photon (IMRT) and carbon ion (CIRT) treatments based on cumulative biological effect, incorporating both the variable relative biological effect of carbon ions and the fractionation effect within the linear quadratic model. The method is demonstrated for 6 glioblastoma patients in comparison with the current clinical standard of independently optimized CIRT-IMRT plans. RESULTS Compared with the reference plan, joint optimization strategies yield inhomogeneous photon and carbon ion dose distributions that cumulatively deliver a homogeneous biological effect distribution. In the optimal distributions, the dose to CTV is mostly delivered by photons and carbon ions are restricted to the GTV with variations depending on tumor size and location. Improvements in conformity of high-dose regions are reflected by a mean EQD2 reduction of 3.29 ± 1.22 Gy in a dose fall-off margin around the CTV. Carbon ions may deliver higher doses to the center of the GTV, and photon contributions are increased at interfaces with CTV and critical structures. This results in a mean EQD2 reduction of 8.3 ± 2.28 Gy, in which the brain stem abuts the target volumes. CONCLUSIONS We have developed a biophysical model to optimize combined photon-carbon ion treatments. For 6 glioblastoma patient cases, we show that our approach results in a more targeted application of carbon ions that (1) reduces dose in normal tissues within the target volume, which can only be protected through fractionation; and (2) boosts central target volume regions to reduce integral dose. Joint optimization of IMRT-CIRT treatments enable the exploration of a new spectrum of plans that can better address physical and radiobiological treatment planning challenges.
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Affiliation(s)
- Amit Ben Antony Bennan
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany; Medical Faculty, Heidelberg University, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany.
| | - Jan Unkelbach
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| | - Niklas Wahl
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Patrick Salome
- Medical Faculty, Heidelberg University, Heidelberg, Germany; Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ)
| | - Mark Bangert
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany
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Schuppert C, Paul A, Nill S, Schwahofer A, Debus J, Sterzing F. A treatment planning study of combined carbon ion-beam plus photon intensity-modulated radiotherapy. Phys Imaging Radiat Oncol 2020; 15:16-22. [PMID: 33458321 PMCID: PMC7807875 DOI: 10.1016/j.phro.2020.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Combined photon intensity-modulated radiotherapy (IMRT) and sequential dose-escalated carbon ion beam therapy (IBT) is a technically advanced treatment option for head and neck malignancies. We proposed and evaluated an integrated planning strategy as opposed to an established and largely separated planning workflow. MATERIALS AND METHODS Ten patients with representative malignancies of the head and neck region underwent combined carbon-photon radiotherapy (RT) in our facilities. Clinical plans were created according to the separated workflow with independent optimization stages for both modalities. Experimental plans incorporated the existing carbon IBT dose distribution into the optimization stage of a step-and-shoot photon IMRT (bias dose planning). RESULTS Cumulative dose distributions showed statistically significant differences between the two planning strategies and were predominantly in favor of the integrated approach. As such, target irradiation was generally maintained or even improved in a subset of metrics, while normal tissue sparing was widely enhanced; for instance, in the ipsilateral temporal lobe with median Dmean of -16% (p < 0.001). Maximum doses D1% (with adjustment for different fractionation) fell below thresholds for toxicity risk in a minority of instances, where they were previously exceeded. Integral dose did not differ significantly. CONCLUSIONS Our findings indicate that combination planning of carbon-photon RT for head and neck malignancies may benefit from a proposed bias dose method, yielding favorable dose distribution characteristics and a streamlined planning workflow with fewer plan revisions. Further research is necessary to validate these observations in terms of robustness and their potential for higher tumor control.
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Affiliation(s)
- Christopher Schuppert
- Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Angela Paul
- Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Simeon Nill
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, United Kingdom
| | - Andrea Schwahofer
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Florian Sterzing
- Department of Radiation Oncology and Radiation Therapy, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
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