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Li H, Mayr NA, Griffin RJ, Zhang H, Pokhrel D, Grams M, Penagaricano J, Chang S, Spraker MB, Kavanaugh J, Lin L, Sheikh K, Mossahebi S, Simone CB, Roberge D, Snider JW, Sabouri P, Molineu A, Xiao Y, Benedict SH. Overview and Recommendations for Prospective Multi-institutional Spatially Fractionated Radiation Therapy Clinical Trials. Int J Radiat Oncol Biol Phys 2024; 119:737-749. [PMID: 38110104 PMCID: PMC11162930 DOI: 10.1016/j.ijrobp.2023.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/30/2023] [Accepted: 12/09/2023] [Indexed: 12/20/2023]
Abstract
PURPOSE The highly heterogeneous dose delivery of spatially fractionated radiation therapy (SFRT) is a profound departure from standard radiation planning and reporting approaches. Early SFRT studies have shown excellent clinical outcomes. However, prospective multi-institutional clinical trials of SFRT are still lacking. This NRG Oncology/American Association of Physicists in Medicine working group consensus aimed to develop recommendations on dosimetric planning, delivery, and SFRT dose reporting to address this current obstacle toward the design of SFRT clinical trials. METHODS AND MATERIALS Working groups consisting of radiation oncologists, radiobiologists, and medical physicists with expertise in SFRT were formed in NRG Oncology and the American Association of Physicists in Medicine to investigate the needs and barriers in SFRT clinical trials. RESULTS Upon reviewing the SFRT technologies and methods, this group identified challenges in several areas, including the availability of SFRT, the lack of treatment planning system support for SFRT, the lack of guidance in the physics and dosimetry of SFRT, the approximated radiobiological modeling of SFRT, and the prescription and combination of SFRT with conventional radiation therapy. CONCLUSIONS Recognizing these challenges, the group further recommended several areas of improvement for the application of SFRT in cancer treatment, including the creation of clinical practice guidance documents, the improvement of treatment planning system support, the generation of treatment planning and dosimetric index reporting templates, and the development of better radiobiological models through preclinical studies and through conducting multi-institution clinical trials.
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Affiliation(s)
- Heng Li
- Department of Radiation Oncology, John Hopkins University, Baltimore, Maryland.
| | - Nina A Mayr
- College of Human Medicine, Michigan State University, East Lansing, Michigan
| | - Robert J Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Science, Little Rock, Arkansas
| | - Hualin Zhang
- Department of Radiation Oncology, University of Southern California, Los Angeles, California
| | - Damodar Pokhrel
- Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky
| | - Michael Grams
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Jose Penagaricano
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida
| | - Sha Chang
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina
| | | | - James Kavanaugh
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Liyong Lin
- Department of Radiation Oncology, Emory University, Atlanta, Georgia
| | - Khadija Sheikh
- Department of Radiation Oncology, John Hopkins University, Baltimore, Maryland
| | - Sina Mossahebi
- Department of Radiation Oncology, University of Maryland, Baltimore, Maryland
| | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, New York
| | - David Roberge
- Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada
| | - James W Snider
- South Florida Proton Therapy Institute, 5280 Linton Blvd, Delray Beach, Florida
| | - Pouya Sabouri
- Department of Radiation Oncology, University of Arkansas for Medical Science, Little Rock, Arkansas
| | - Andrea Molineu
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Ying Xiao
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stanley H Benedict
- Department of Radiation Oncology, University of California, Davis, Sacramento, California
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Xu Z, Balik S, Woods K, Shen Z, Cheng C, Cui J, Gallogly H, Chang E, Lukas L, Lim A, Natsuaki Y, Ye J, Ma L, Zhang H. Dosimetric validation for prospective clinical trial on GRID collimator-based spatially fractionated radiation therapy: Dose metrics consistency and heterogeneous pattern reproducibility. J Appl Clin Med Phys 2024:e14410. [PMID: 38810092 DOI: 10.1002/acm2.14410] [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: 11/17/2023] [Revised: 04/23/2024] [Accepted: 05/09/2024] [Indexed: 05/31/2024] Open
Abstract
PURPOSE The purpose of this study is to characterize the dosimetric properties of a commercial brass GRID collimator for high energy photon beams including 15 and 10 MV. Then, the difference in dosimetric parameters of GRID beams among different energies and linacs was evaluated. METHOD A water tank scanning system was used to acquire the dosimetric parameters, including the percentage depth dose (PDD), beam profiles, peak to valley dose ratios (PVDRs), and output factors (OFs). The profiles at various depths were measured at 100 cm source to surface distance (SSD), and field sizes of 10 × 10 cm2 and 20 × 20 cm2 on three linacs. The PVDRs and OFs were measured and compared with the treatment planning system (TPS) calculations. RESULTS Compared with the open beam data, there were noticeable changes in PDDs of GRID fields across all the energies. The GRID fields demonstrated a maximal of 3 mm shift in dmax (Truebeam STX, 15MV, 10 × 10 cm2). The PVDR decreased as beam energy increases. The difference in PVDRs between Trilogy and Truebeam STx using 6MV and 15MV was 1.5% ± 4.0% and 2.1% ± 4.3%, respectively. However, two Truebeam linacs demonstrated less than 2% difference in PVDRs. The OF of the GRID field was dependent on the energy and field size. The measured PDDs, PVDRs, and OFs agreed with the TPS calculations within 3% difference. The TPS calculations agreed with the measurements when using 1 mm calculation resolution. CONCLUSION The dosimetric characteristics of high-energy GRID fields, especially PVDR, significantly differ from those of low-energy GRID fields. Two Truebeam machines are interchangeable for GRID therapy, while a pronounced difference was observed between Truebeam and Trilogy. A series of empirical equations and reference look-up tables for GRID therapy can be generated to facilitate clinical applications.
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Affiliation(s)
- Zhengzheng Xu
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Salim Balik
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Kaley Woods
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Zhilei Shen
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Chihyao Cheng
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Jing Cui
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Haihong Gallogly
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Eric Chang
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Lauren Lukas
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Andrew Lim
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Yutaka Natsuaki
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Jason Ye
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Lijun Ma
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
| | - Hualin Zhang
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Radiation Oncology, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
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Mayr NA, Mohiuddin M, Snider JW, Zhang H, Griffin RJ, Amendola BE, Hippe DS, Perez NC, Wu X, Lo SS, Regine WF, Simone CB. Practice Patterns of Spatially Fractionated Radiation Therapy: A Clinical Practice Survey. Adv Radiat Oncol 2024; 9:101308. [PMID: 38405319 PMCID: PMC10885580 DOI: 10.1016/j.adro.2023.101308] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/26/2023] [Indexed: 02/27/2024] Open
Abstract
Purpose Spatially fractionated radiation therapy (SFRT) is increasingly used for bulky advanced tumors, but specifics of clinical SFRT practice remain elusive. This study aimed to determine practice patterns of GRID and Lattice radiation therapy (LRT)-based SFRT. Methods and Materials A survey was designed to identify radiation oncologists' practice patterns of patient selection for SFRT, dosing/planning, dosimetric parameter use, SFRT platforms/techniques, combinations of SFRT with conventional external beam radiation therapy (cERT) and multimodality therapies, and physicists' technical implementation, delivery, and quality procedures. Data were summarized using descriptive statistics. Group comparisons were analyzed with permutation tests. Results The majority of practicing radiation oncologists (United States, 100%; global, 72.7%) considered SFRT an accepted standard-of-care radiation therapy option for bulky/advanced tumors. Treatment of metastases/recurrences and nonmetastatic primary tumors, predominantly head and neck, lung cancer and sarcoma, was commonly practiced. In palliative SFRT, regimens of 15 to 18 Gy/1 fraction predominated (51.3%), and in curative-intent treatment of nonmetastatic tumors, 15 Gy/1 fraction (28.0%) and fractionated SFRT (24.0%) were most common. SFRT was combined with cERT commonly but not always in palliative (78.6%) and curative-intent (85.7%) treatment. SFRT-cERT time sequencing and cERT dose adjustments were variable. In curative-intent treatment, concurrent chemotherapy and immunotherapy were found acceptable by 54.5% and 28.6%, respectively. Use of SFRT dosimetric parameters was highly variable and differed between GRID and LRT. SFRT heterogeneity dosimetric parameters were more commonly used (P = .008) and more commonly thought to influence local control (peak dose, P = .008) in LRT than in GRID therapy. Conclusions SFRT has already evolved as a clinical practice pattern for advanced/bulky tumors. Major treatment approaches are consistent and follow the literature, but SFRT-cERT combination/sequencing and clinical utilization of dosimetric parameters are variable. These areas may benefit from targeted education and standardization, and knowledge gaps may be filled by incorporating identified inconsistencies into future clinical research.
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Affiliation(s)
- Nina A. Mayr
- College of Human Medicine, Michigan State University, East Lansing, Michigan
| | - Majid Mohiuddin
- Radiation Oncology Consultants and Northwestern Proton Center, Warrenville, Illinois
| | - James W. Snider
- Radiation Oncology, South Florida Proton Therapy Institute, Delray Beach, Florida
| | - Hualin Zhang
- Department of Radiation Oncology, University of Southern California, Los Angeles, California
| | - Robert J. Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | | | - Daniel S. Hippe
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, Washington
| | | | - Xiaodong Wu
- Executive Medical Physics Associates, Miami, Florida
| | - Simon S. Lo
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - William F. Regine
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Charles B. Simone
- Department of Radiation Oncology, New York Proton Center, New York, New York
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Gaudreault M, Chang D, Kron T, Siva S, Chander S, Hardcastle N, Yeo A. Development of an automated treatment planning approach for lattice radiation therapy. Med Phys 2024; 51:682-693. [PMID: 37797078 DOI: 10.1002/mp.16761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/29/2023] [Accepted: 09/14/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND Lattice radiation therapy (LRT) alternates regions of high and low doses within the target. The heterogeneous dose distribution is delivered to a geometrical structure of vertices segmented inside the tumor. LRT is typically used to treat patients with large tumor volumes with cytoreduction intent. Due to the geometric complexity of the target volume and the required dose distribution, LRT treatment planning demands additional resources, which may limit clinical integration. PURPOSE We introduce a fully automated method to (1) generate an ordered lattice of vertices with various sizes and center-to-center distances and (2) perform dose optimization and calculation. We aim to report the dosimetry associated with these lattices to help clinical decision-making. METHODS Sarcoma cancer patients with tumor volume between 100 cm3 and 1500 cm3 who received radiotherapy treatment between 2010 and 2018 at our institution were considered for inclusion. Automated segmentation and dose optimization/calculation were performed by using the Eclipse Scripting Application Programming Interface (ESAPI, v16, Varian Medical Systems, Palo Alto, USA). Vertices were modeled by spheres segmented within the gross tumor volume (GTV) with 1 cm/1.5 cm/2 cm diameters (LRT-1 cm/1.5 cm/2 cm) and 2 to 5 cm center-to-center distance on square lattices alternating along the superior-inferior direction. Organs at risk were modeled by subtracting the GTV from the body structure (body-GTV). The prescription dose was that 50% of the vertice volume should receive at least 20 Gy in one fraction. The automated dose optimization included three stages. The vertices optimization objectives were refined during optimization according to their values at the end of the first and second stages. Lattices were classified according to a score based on the minimization of body-GTV max dose and the maximization of GTV dose uniformity (measured with the equivalent uniform dose [EUD]), GTV dose heterogeneity (measured with the GTV D90%/D10% ratio), and the number of patients with more than one vertex inserted in the GTV. Plan complexity was measured with the modulation complexity score (MCS). Correlations were assessed with the Spearman correlation coefficient (r) and its associated p-value. RESULTS Thirty-three patients with GTV volumes between 150 and 1350 cm3 (median GTV volume = 494 cm3 , IQR = 272-779 cm3 were included. The median time required for segmentation/planning was 1 min/21 min. The number of vertices was strongly correlated with GTV volume in each LRT lattice for each center-to-center distance (r > 0.85, p-values < 0.001 in each case). Lattices with center-to-center distance = 2.5 cm/3 cm/3.5 cm in LRT-1.5 cm and center-to-center distance = 4 cm in LRT-1 cm had the best scores. These lattices were characterized by high heterogeneity (median GTV D90%/D10% between 0.06 and 0.19). The generated plans were moderately complex (median MCS ranged between 0.19 and 0.40). CONCLUSIONS The automated LRT planning method allows for the efficacious generation of vertices arranged in an ordered lattice and the refinement of planning objectives during dose optimization, enabling the systematic evaluation of LRT dosimetry from various lattice geometries.
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Affiliation(s)
- Mathieu Gaudreault
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
| | - David Chang
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
- Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, New South Wales, Australia
| | - Shankar Siva
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
- Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Sarat Chander
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
- Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Nicholas Hardcastle
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, New South Wales, Australia
| | - Adam Yeo
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
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Tucker WW, Mazur TR, Schmidt MC, Hilliard J, Badiyan S, Spraker MB, Kavanaugh JA. Script-based implementation of automatic grid placement for lattice stereotactic body radiation therapy. Phys Imaging Radiat Oncol 2024; 29:100549. [PMID: 38380154 PMCID: PMC10876586 DOI: 10.1016/j.phro.2024.100549] [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: 09/15/2023] [Revised: 01/26/2024] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Background and purpose Spatially fractionated radiation therapy (SFRT) has demonstrated promising clinical response in treating large tumors with heterogeneous dose distributions. Lattice stereotactic body radiation therapy (SBRT) is an SFRT technique that leverages inverse optimization to precisely localize regions of high and lose dose within disease. The aim of this study was to evaluate an automated heuristic approach to sphere placement in lattice SBRT treatment planning. Materials and methods A script-based algorithm for sphere placement in lattice SBRT based on rules described by protocol was implemented within a treatment planning system. The script was applied to 22 treated cases and sphere distributions were compared with manually placed spheres in terms of number of spheres, number of protocol violations, and time required to place spheres. All cases were re-planned using script-generated spheres and plan quality was compared with clinical plans. Results The mean number of spheres placed excluding those that violate rules was greater using the script (13.8) than that obtained by either dosimetrist (10.8 and 12.0, p < 0.001 and p = 0.003) or physicist (12.7, p = 0.061). The mean time required to generate spheres was significantly less using the script (2.5 min) compared to manual placement by dosimetrists (25.0 and 29.9 min) and physicist (19.3 min). Plan quality indices were similar in all cases with no significant differences, and OAR constraints remained met on all plans except two. Conclusion A script placed spheres for lattice SBRT according to institutional protocol rules. The script-produced placement was superior to that of manually-specified spheres, as characterized by sphere number and rule violations.
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Affiliation(s)
- Wesley W. Tucker
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Thomas R. Mazur
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Matthew C. Schmidt
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Jessica Hilliard
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Shahed Badiyan
- Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO 63110 USA
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Grams MP, Deufel CL, Kavanaugh JA, Corbin KS, Ahmed SK, Haddock MG, Lester SC, Ma DJ, Petersen IA, Finley RR, Lang KG, Spreiter SS, Park SS, Owen D. Clinical aspects of spatially fractionated radiation therapy treatments. Phys Med 2023; 111:102616. [PMID: 37311338 DOI: 10.1016/j.ejmp.2023.102616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/06/2023] [Accepted: 05/30/2023] [Indexed: 06/15/2023] Open
Abstract
PURPOSE To provide clinical guidance for centers wishing to implement photon spatially fractionated radiation therapy (SFRT) treatments using either a brass grid or volumetric modulated arc therapy (VMAT) lattice approach. METHODS We describe in detail processes which have been developed over the course of a 3-year period during which our institution treated over 240 SFRT cases. The importance of patient selection, along with aspects of simulation, treatment planning, quality assurance, and treatment delivery are discussed. Illustrative examples involving clinical cases are shown, and we discuss safety implications relevant to the heterogeneous dose distributions. RESULTS SFRT can be an effective modality for tumors which are otherwise challenging to manage with conventional radiation therapy techniques or for patients who have limited treatment options. However, SFRT has several aspects which differ drastically from conventional radiation therapy treatments. Therefore, the successful implementation of an SFRT treatment program requires the multidisciplinary expertise and collaboration of physicians, physicists, dosimetrists, and radiation therapists. CONCLUSIONS We have described methods for patient selection, simulation, treatment planning, quality assurance and delivery of clinical SFRT treatments which were built upon our experience treating a large patient population with both a brass grid and VMAT lattice approach. Preclinical research and patient trials aimed at understanding the mechanism of action are needed to elucidate which patients may benefit most from SFRT, and ultimately expand its use.
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Affiliation(s)
- Michael P Grams
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
| | - Christopher L Deufel
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - James A Kavanaugh
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Kimberly S Corbin
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Safia K Ahmed
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Michael G Haddock
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Scott C Lester
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Daniel J Ma
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Ivy A Petersen
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Randi R Finley
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Karen G Lang
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Sheri S Spreiter
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Sean S Park
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Dawn Owen
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
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Zhang W, Li W, Lin Y, Wang F, Chen RC, Gao H. TVL1-IMPT: Optimization of Peak-to-Valley Dose Ratio Via Joint Total-Variation and L1 Dose Regularization for Spatially Fractionated Pencil-Beam-Scanning Proton Therapy. Int J Radiat Oncol Biol Phys 2023; 115:768-778. [PMID: 36155212 PMCID: PMC10155885 DOI: 10.1016/j.ijrobp.2022.09.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 07/18/2022] [Accepted: 09/08/2022] [Indexed: 02/04/2023]
Abstract
PURPOSE Proton minibeam radiation therapy (pMBRT) is a novel proton modality of spatially fractionated RT. pMBRT can reduce the radiation damage to normal tissues via biological dose sparing of high peak-to-valley dose ratio (PVDR). This work will develop a new spatially fractionated IMPT treatment planning method for pMBRT that jointly optimizes the plan quality and maximizes the PVDR. METHODS The new optimization method simultaneously maximizes the normal-tissue PVDR and optimizes the dose distribution at tumor targets and organs at risk. The PVDR maximization is through the joint total variation (TV) and L1 regularization with respect to the normal-tissue dose. That is, the beam-eye view projects dose slices of several depths for each beam angle; the TV of dose is maximized, corresponding to the PVDR maximization; and the L1 of dose is minimized, corresponding to the minimization of the organs-at-risk dose and maximization of survival fraction (SF). RESULTS The new IMPT method with TV and L1 regularization was validated in comparison with the conventional IMPT method for pMBRT in several clinical cases. The results show that TVL1 provided larger PVDR and SF than the conventional IMPT method for biological sparing of normal tissues, with preserved plan quality in terms of physical dose distribution. CONCLUSIONS A new spatially fractionated IMPT treatment planning method was developed for pMBRT that can optimize and improve normal-tissue PVDR and SF by incorporating TV and L1 dose regularization with properly chosen regularization parameters into IMPT.
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Affiliation(s)
- Weijie Zhang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Yuting Lin
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Fen Wang
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Ronald C Chen
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas.
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Halthore A, Fellows Z, Tran A, Deville C, Wright JL, Meyer J, Li H, Sheikh K. Treatment Planning of Bulky Tumors Using Pencil Beam Scanning Proton GRID Therapy. Int J Part Ther 2022; 9:40-49. [PMID: 36721485 PMCID: PMC9875826 DOI: 10.14338/ijpt-22-00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/02/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose To compare spatially fractionated radiation therapy (GRID) treatment planning techniques using proton pencil-beam-scanning (PBS) and photon therapy. Materials and Methods PBS and volumetric modulated arc therapy (VMAT) GRID plans were retrospectively generated for 5 patients with bulky tumors. GRID targets were arranged along the long axis of the gross tumor, spaced 2 and 3 cm apart, and treated with a prescription of 18 Gy. PBS plans used 2- to 3-beam multiple-field optimization with robustness evaluation. Dosimetric parameters including peak-to-edge ratio (PEDR), ratio of dose to 90% of the valley to dose to 10% of the peak VPDR(D90/D10), and volume of normal tissue receiving at least 5 Gy (V5) and 10 Gy (V10) were calculated. The peak-to-valley dose ratio (PVDR), VPDR(D90/D10), and organ-at-risk doses were prospectively assessed in 2 patients undergoing PBS-GRID with pretreatment quality assurance computed tomography (QACT) scans. Results PBS and VMAT GRID plans were generated for 5 patients with bulky tumors. Gross tumor volume values ranged from 826 to 1468 cm3. Peak-to-edge ratio for PBS was higher than for VMAT for both spacing scenarios (2-cm spacing, P = .02; 3-cm spacing, P = .01). VPDR(D90/D10) for PBS was higher than for VMAT (2-cm spacing, P = .004; 3-cm spacing, P = .002). Normal tissue V5 was lower for PBS than for VMAT (2-cm spacing, P = .03; 3-cm spacing, P = .02). Normal tissue mean dose was lower with PBS than with VMAT (2-cm spacing, P = .03; 3-cm spacing, P = .02). Two patients treated using PBS GRID and assessed with pretreatment QACT scans demonstrated robust PVDR, VPDR(D90/D10), and organs-at-risk doses. Conclusions The PEDR was significantly higher for PBS than VMAT plans, indicating lower target edge dose. Normal tissue mean dose was significantly lower with PBS than VMAT. PBS GRID may result in lower normal tissue dose compared with VMAT plans, allowing for further dose escalation in patients with bulky disease.
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Affiliation(s)
- Aditya Halthore
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Zachary Fellows
- Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Anh Tran
- Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Curtiland Deville
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Jean L. Wright
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Jeffrey Meyer
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Heng Li
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Khadija Sheikh
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
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9
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McAuley GA, Lim CJ, Teran AV, Slater JD, Wroe AJ. Monte Carlo evaluation of high-gradient magnetically focused planar proton minibeams in a passive nozzle. Phys Med Biol 2022; 67. [PMID: 35421853 DOI: 10.1088/1361-6560/ac678b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/14/2022] [Indexed: 11/12/2022]
Abstract
Objective. To investigate the potential of using a single quadrupole magnet with a high magnetic field gradient to create planar minibeams suitable for clinical applications of proton minibeam radiation therapy.Approach. We performed Monte Carlo simulations involving single quadrupole Halbach cylinders in a passively scattered nozzle in clinical use for proton therapy. Pencil beams produced by the nozzle of 10-15 mm initial diameters and particle range of ∼10-20 cm in water were focused by magnets with field gradients of 225-350 T m-1and cylinder lengths of 80-110 mm to produce very narrow elongated (planar) beamlets. The corresponding dose distributions were scored in a water phantom. Composite minibeam dose distributions composed from three beamlets were created by laterally shifting copies of the single beamlet distribution to either side of a central beamlet. Modulated beamlets (with 18-30 mm nominal central SOBP) and corresponding composite dose distributions were created in a similar manner. Collimated minibeams were also compared with beams focused using one magnet/particle range combination.Main results. The focusing magnets produced planar beamlets with minimum lateral FWHM of ∼1.1-1.6 mm. Dose distributions composed from three unmodulated beamlets showed a high degree of proximal spatial fractionation and a homogeneous target dose. Maximal peak-to-valley dose ratios (PVDR) for the unmodulated beams ranged from 32 to 324, and composite modulated beam showed maximal PVDR ranging from 32 to 102 and SOBPs with good target dose coverage.Significance.Advantages of the high-gradient magnets include the ability to focus beams with phase space parameters that reflect beams in operation today, and post-waist particle divergence allowing larger beamlet separations and thus larger PVDR. Our results suggest that high gradient quadrupole magnets could be useful to focus beams of moderate emittance in clinical proton therapy.
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Affiliation(s)
- Grant A McAuley
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America
| | - Crystal J Lim
- School of Medicine, Loma Linda University, Loma Linda, CA United States of America
| | - Anthony V Teran
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America.,Orange County CyberKnife and Radiation Oncology Center, Fountain Valley, CA, United States of America
| | - Jerry D Slater
- Department of Radiation Medicine, Loma Linda University, Loma Linda CA, United States of America
| | - Andrew J Wroe
- School of Medicine, Loma Linda University, Loma Linda, CA United States of America.,Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, United States of America.,Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
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10
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Pokhrel D, Bernard ME, Mallory R, St Clair W, Kudrimoti M. Conebeam CT-guided 3D MLC-based spatially fractionated radiation therapy for bulky masses. J Appl Clin Med Phys 2022; 23:e13608. [PMID: 35446479 PMCID: PMC9121033 DOI: 10.1002/acm2.13608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/03/2022] [Accepted: 03/23/2022] [Indexed: 11/17/2022] Open
Abstract
For fast, safe, and effective management of large and bulky (≥8 cm) non‐resectable tumors, we have developed a conebeam CT‐guided three‐dimensional (3D)‐conformal MLC‐based spatially fractionated radiation therapy (SFRT) treatment. Using an in‐house MLC‐fitting algorithm, Millennium 120 leaves were fitted to the gross tumor volume (GTV) generating 1‐cm diameter holes at 2‐cm center‐to‐center distance at isocenter. SFRT plans of 15 Gy were generated using four to six coplanar crossfire gantry angles 60° apart with a 90° collimator, differentially weighted with 6‐ or 10‐MV beams. A dose was calculated using AcurosXB algorithm, generating sieve‐like dose channels without post‐processing the physician‐drawn GTV contour within an hour of CT simulation allowing for the same day treatment. In total, 50 extracranial patients have been planned and treated using this method, comprising multiple treatment sites. This novel MLC‐fitting algorithm provided excellent dose parameters with mean GTV (V7.5 Gy) and mean GTV doses of 53.2% and 7.9 Gy, respectively, for 15 Gy plans. Average peak‐to‐valley dose ratio was 3.2. Mean beam‐on time was 3.32 min, and treatment time, including patient setup and CBCT to beam‐off, was within 15 min. Average 3D couch correction from original skin‐markers was <1.0 cm. 3D MLC‐based SFRT plans enhanced target dose for bulky masses, including deep‐seated large tumors while protecting skin and adjacent critical organs. Additionally, it provides the same day, safe, effective, and convenient treatment by eliminating the risk to therapists and patients from heavy gantry‐mounted physical GRID‐block—we recommend other centers to use this simple and clinically useful method. This rapid SFRT planning technique is easily adoptable in any radiation oncology clinic by eliminating the need for plan optimization and patient‐specific quality assurance times while providing dosimetry information in the treatment planning system. This potentially allows for dose‐escalation to deep‐seated masses to debulk unresectable large tumors providing an option for neoadjuvant treatment. An outcome study of clinical trial is underway.
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Affiliation(s)
- Damodar Pokhrel
- Department of Radiation, Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mark E Bernard
- Department of Radiation, Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Richard Mallory
- Department of Radiation, Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - William St Clair
- Department of Radiation, Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mahesh Kudrimoti
- Department of Radiation, Medicine, University of Kentucky, Lexington, Kentucky, USA
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11
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Grams MP, Tseung HSWC, Ito S, Zhang Y, Owen D, Park SS, Ahmed SK, Petersen IA, Haddock MG, Harmsen WS, Ma DJ. A Dosimetric Comparison of Lattice, Brass, and Proton Grid Therapy Treatment Plans. Pract Radiat Oncol 2022; 12:e442-e452. [DOI: 10.1016/j.prro.2022.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 02/28/2022] [Accepted: 03/09/2022] [Indexed: 11/28/2022]
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12
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Moghaddasi L, Reid P, Bezak E, Marcu LG. Radiobiological and Treatment-Related Aspects of Spatially Fractionated Radiotherapy. Int J Mol Sci 2022; 23:3366. [PMID: 35328787 PMCID: PMC8954016 DOI: 10.3390/ijms23063366] [Citation(s) in RCA: 1] [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: 02/19/2022] [Revised: 03/13/2022] [Accepted: 03/17/2022] [Indexed: 11/17/2022] Open
Abstract
The continuously evolving field of radiotherapy aims to devise and implement techniques that allow for greater tumour control and better sparing of critical organs. Investigations into the complexity of tumour radiobiology confirmed the high heterogeneity of tumours as being responsible for the often poor treatment outcome. Hypoxic subvolumes, a subpopulation of cancer stem cells, as well as the inherent or acquired radioresistance define tumour aggressiveness and metastatic potential, which remain a therapeutic challenge. Non-conventional irradiation techniques, such as spatially fractionated radiotherapy, have been developed to tackle some of these challenges and to offer a high therapeutic index when treating radioresistant tumours. The goal of this article was to highlight the current knowledge on the molecular and radiobiological mechanisms behind spatially fractionated radiotherapy and to present the up-to-date preclinical and clinical evidence towards the therapeutic potential of this technique involving both photon and proton beams.
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Affiliation(s)
- Leyla Moghaddasi
- Department of Medical Physics, Austin Health, Ballarat, VIC 3350, Australia;
- School of Physical Sciences, University of Adelaide, Adelaide, SA 5001, Australia;
| | - Paul Reid
- Radiation Health, Environment Protection Authority, Adelaide, SA 5000, Australia;
| | - Eva Bezak
- School of Physical Sciences, University of Adelaide, Adelaide, SA 5001, Australia;
- Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
| | - Loredana G. Marcu
- Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
- Faculty of Informatics and Science, University of Oradea, 1 Universitatii Str., 410087 Oradea, Romania
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13
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Smith BR, M S NPN, M S TJG, M S KAP, Hill PM, Yu J, Gutiérrez AN, Md BGA, Hyer DE. The dosimetric enhancement of GRID profiles using an external collimator in pencil beam scanning proton therapy. Med Phys 2022; 49:2684-2698. [PMID: 35120278 PMCID: PMC9007854 DOI: 10.1002/mp.15523] [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: 07/29/2021] [Revised: 11/22/2021] [Accepted: 01/23/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The radiobiological benefits afforded by spatially fractionated (GRID) radiation therapy pairs well with the dosimetric advantages of proton therapy. Inspired by the emergence of energy-layer specific collimators in pencil beam scanning (PBS), this work investigates how the spot spacing and collimation can be optimized to maximize the therapeutic gains of a GRID treatment while demonstrating the integration of a dynamic collimation system (DCS) within a commercial beam line to deliver GRID treatments and experimentally benchmark Monte Carlo calculation methods. METHODS GRID profiles were experimentally benchmarked using a clinical DCS prototype that was mounted to the nozzle of the IBA Dedicated Nozzle system. Integral depth dose (IDD) curves and lateral profiles were measured for uncollimated and GRID-collimated beamlets. A library of collimated GRID dose distributions were simulated by placing beamlets within a specified uniform grid and weighting the beamlets to achieve a volume-averaged tumor cell survival equivalent to an open field delivery. The healthy tissue sparing afforded by the GRID distribution was then estimated across a range of spot spacings and collimation widths, which were later optimized based on the radiosensitivity of the tumor cell line and the nominal spot size of the PBS system. This was accomplished by using validated models of the IBA Universal and Dedicated nozzles. RESULTS Excellent agreement was observed between the measured and simulated profiles. The IDDs matched above 98.7% when analyzed using a 1%/1 mm gamma criteria with some minor deviation observed near the Bragg peak for higher beamlet energies. Lateral profile distributions predicted using Monte Carlo methods agreed well with the measured profiles; a gamma passing rate of 95% or higher was observed for all in-depth profiles examined using a 3%/2 mm criteria. Additional collimation was shown to improve PBS GRID treatments by sharpening the lateral penumbra of the beamlets but creates a tradeoff between enhancing the valley-to-peak ratio of the GRID delivery and the dose-volume effect. The optimal collimation width and spot spacing changed as a function of the tumor cell radiosensitivity, dose, and spot size. In general, a spot spacing below 2.0 cm with a collimation less than 1.0 cm provided a superior dose distribution among the specific cases studied. CONCLUSIONS The ability to customize a GRID dose distribution using different collimation sizes and spot spacings is a useful advantage, especially to maximize the overall therapeutic benefit. In this regard, the capabilities of the DCS, and perhaps alternative dynamic collimators, can be used to enhance GRID treatments. Physical dose models calculated using Monte Carlo methods were experimentally benchmarked in water and were found to accurately predict the respective dose distributions of uncollimated and DCS-collimated GRID profiles. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Blake R Smith
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, 52242 Iowa
| | - Nicholas P Nelson M S
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI, 53705
| | | | | | - Patrick M Hill
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI, 53792
| | - Jen Yu
- Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, 8900 N. Kendall Drive, Miami, FL, 33176
| | - Alonso N Gutiérrez
- Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, 8900 N. Kendall Drive, Miami, FL, 33176
| | - Bryan G Allen Md
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, 52242 Iowa
| | - Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, 52242 Iowa
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14
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Abstract
AbstractSpatially fractionated radiation therapy (SFRT) challenges some of the classical dogmas in conventional radiotherapy. The highly modulated spatial dose distributions in SFRT have been shown to lead, both in early clinical trials and in small animal experiments, to a significant increase in normal tissue dose tolerances. Tumour control effectiveness is maintained or even enhanced in some configurations as compared with conventional radiotherapy. SFRT seems to activate distinct radiobiological mechanisms, which have been postulated to involve bystander effects, microvascular alterations and/or immunomodulation. Currently, it is unclear which is the dosimetric parameter which correlates the most with both tumour control and normal tissue sparing in SFRT. Additional biological experiments aiming at parametrizing the relationship between the irradiation parameters (beam width, spacing, peak-to-valley dose ratio, peak and valley doses) and the radiobiology are needed. A sound knowledge of the interrelation between the physical parameters in SFRT and the biological response would expand its clinical use, with a higher level of homogenisation in the realisation of clinical trials. This manuscript reviews the state of the art of this promising therapeutic modality, the current radiobiological knowledge and elaborates on future perspectives.
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15
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Masson I, Dutreix M, Supiot S. [Innovation in radiotherapy in 2021]. Bull Cancer 2020; 108:42-49. [PMID: 33303195 DOI: 10.1016/j.bulcan.2020.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 10/26/2020] [Indexed: 11/25/2022]
Affiliation(s)
- Ingrid Masson
- Département de radiothérapie, Institut de cancérologie de l'Ouest René-Gauducheau, boulevard Jacques-Monod, 44805 Saint-Herblain, France
| | - Marie Dutreix
- Institut Curie, Université PSL, CNRS, Inserm, UMR 3347; Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Stéphane Supiot
- Département de radiothérapie, Institut de cancérologie de l'Ouest René-Gauducheau, boulevard Jacques-Monod, 44805 Saint-Herblain, France; Centre de Recherche en Cancéro-Immunologie Nantes/Angers (CRCINA, UMR 892 Inserm), Institut de Recherche en Santé de l'Université de Nantes, Nantes cedex 1, France.
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16
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Griffin RJ, Ahmed MM, Amendola B, Belyakov O, Bentzen SM, Butterworth KT, Chang S, Coleman CN, Djonov V, Formenti SC, Glatstein E, Guha C, Kalnicki S, Le QT, Loo BW, Mahadevan A, Massaccesi M, Maxim PG, Mohiuddin M, Mohiuddin M, Mayr NA, Obcemea C, Petersson K, Regine W, Roach M, Romanelli P, Simone CB, Snider JW, Spitz DR, Vikram B, Vozenin MC, Abdel-Wahab M, Welsh J, Wu X, Limoli CL. Understanding High-Dose, Ultra-High Dose Rate, and Spatially Fractionated Radiation Therapy. Int J Radiat Oncol Biol Phys 2020; 107:766-778. [PMID: 32298811 DOI: 10.1016/j.ijrobp.2020.03.028] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/12/2022]
Abstract
The National Cancer Institute's Radiation Research Program, in collaboration with the Radiosurgery Society, hosted a workshop called Understanding High-Dose, Ultra-High Dose Rate and Spatially Fractionated Radiotherapy on August 20 and 21, 2018 to bring together experts in experimental and clinical experience in these and related fields. Critically, the overall aims were to understand the biological underpinning of these emerging techniques and the technical/physical parameters that must be further defined to drive clinical practice through innovative biologically based clinical trials.
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Affiliation(s)
- Robert J Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Mansoor M Ahmed
- Division of Cancer Treatment and Diagnosis, Rockville, Maryland
| | | | - Oleg Belyakov
- International Atomic Energy Agency, Vienna International Centre, Vienna, Austria
| | - Søren M Bentzen
- Division of Biostatistics and Bioinformatics, University of Maryland, Baltimore, Maryland
| | - Karl T Butterworth
- Centre for Cancer Research and Cell Biology, Queens University Belfast, Belfast, United Kingdom
| | - Sha Chang
- Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Valentin Djonov
- Bern Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Sylvia C Formenti
- Department of Radiation Oncology, Weill Cornell Medicine, New York, New York
| | - Eli Glatstein
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chandan Guha
- Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York
| | - Shalom Kalnicki
- Department of Radiation Oncology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York
| | - Quynh-Thu Le
- Department of Radiation Oncology, Stanford University Medical Center, Stanford, California
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University Medical Center, Stanford, California
| | - Anand Mahadevan
- Department of Radiation Oncology, Geisinger Health Systems, Danville, Pennsylvania
| | - Mariangela Massaccesi
- Department of Radiation Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Peter G Maxim
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana
| | | | | | - Nina A Mayr
- Department of Radiation Oncology, University of Washington Medical Center, Seattle, Washington
| | | | - Kristoffer Petersson
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - William Regine
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mack Roach
- Department of Radiation Oncology & Urology, University of California, San Francisco, San Francisco, California
| | | | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, New York
| | - James W Snider
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Douglas R Spitz
- Free Radical & Radiation Biology Program, University of Iowa, Iowa City, Iowa
| | | | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital, Switzerland
| | - May Abdel-Wahab
- International Atomic Energy Agency Headquarters, Vienna International Centre, Vienna, Austria
| | - James Welsh
- Edward Hines VA Medical Center and Loyola University Stritch School of Medicine, Chicago, Illinois
| | - Xiaodong Wu
- Executive Medical Physics Associates, Miami, Florida; Shanghai Proton and Heavy Ion Center, Shanghai, China
| | - Charles L Limoli
- Department of Radiation Oncology, University of California-Irvine, Irvine, California.
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Charyyev S, Wang CKC. ASSESSMENT OF AMBIENT NEUTRON DOSE EQUIVALENT IN SPATIALLY FRACTIONATED RADIOTHERAPY WITH PROTONS USING PHYSICAL COLLIMATORS. RADIATION PROTECTION DOSIMETRY 2020; 189:190-197. [PMID: 32144416 DOI: 10.1093/rpd/ncaa030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/21/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
New technique is trending in spatially fractionated radiotherapy with protons to utilize the spot scanning together with a physical collimator to obtain minibeams. The primary goal of this study is to quantify ambient neutron dose equivalent (${H}^{\ast }(10)$) due to the secondary neutrons when physical collimator is used to achieve desired minibeams. The ${H}^{\ast }(10)$ per treatment proton dose (D) was assessed using Monte Carlo code TOPAS and measured using WENDI-II detector at different angles (135, 180, 225 and 270 degrees) and distances (11 cm, 58 and 105 cm) from the phantom for two cases: with and without physical collimation. Without collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.0013 to 0.242 mSv/Gy. With collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.017 to 3.23 mSv/Gy. Results show that the secondary neutron dose will increase tenfold when the physical collimator is used. Regardless, it will be low and comparable to the neutron dose produced by conventional passive-scattered proton beams.
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Affiliation(s)
- Serdar Charyyev
- Radiation Oncology and Winship Cancer Institute, Emory University, 1365 Clifton Rd NE, Atlanta, GA 30322, USA
| | - C-K Chris Wang
- Nuclear and Radiological Engineering, Georgia Institute of Technology, 770 State St NW, Atlanta, GA 30332, USA
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18
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Charyyev S, Artz M, Szalkowski G, Chang C, Stanforth A, Lin L, Zhang R, Wang CC. Optimization of hexagonal‐pattern minibeams for spatially fractionated radiotherapy using proton beam scanning. Med Phys 2020; 47:3485-3495. [DOI: 10.1002/mp.14192] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Serdar Charyyev
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | - Mark Artz
- UF Health Proton Therapy Institute Jacksonville FL 32206 USA
| | - Gregory Szalkowski
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
- Department of Radiation Oncology University of North Carolina Chapel Hill NC 27514 USA
| | - Chih‐Wei Chang
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | | | - Liyong Lin
- Department of Radiation Oncology Emory University Atlanta GA 30322 USA
| | - Rongxiao Zhang
- Department of Radiation Oncology Dartmouth College Hanover NH 03755 USA
| | - C.‐K. Chris Wang
- Medical Physics Program Georgia Institute of Technology Atlanta GA 30332 USA
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Karimi AH, Vega-Carrillo HR. Grid therapy vs. conventional radiotherapy - 18 MV treatments: Photoneutron contamination along the maze of a linac bunker. Appl Radiat Isot 2020; 158:109064. [PMID: 32174378 DOI: 10.1016/j.apradiso.2020.109064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/01/2020] [Accepted: 01/27/2020] [Indexed: 10/25/2022]
Abstract
The present Monte Carlo study was devoted to the comparison of photoneutron contamination (per 1 Gy photon dose), along the maze of a radiotherapy bunker, between two 18-MV modalities: grid therapy (with grids made of brass, cerrobend, and lead) and conventional radiotherapy. It was turned out that both in grid therapy and in conventional radiotherapy, with increasing distance from the entrance of treatment hall (toward the maze entrance), fluence and ambient dose equivalent of neutrons decrease. Evidence also shows that in grid therapy, independent of materials used in the grid construction, photoneutron contamination along the maze is 45±6 % larger than conventional radiotherapy.
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Affiliation(s)
- Amir Hossein Karimi
- Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
| | - Hector Rene Vega-Carrillo
- Unidad Academica de Estudios Nucleares de la Universidad Autonoma de Zacatecas C. Cipres 10, Fracc, La Peñuela, 98068, Zacatecas, Zac, Mexico.
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20
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Scholz M. State-of-the-Art and Future Prospects of Ion Beam Therapy: Physical and Radiobiological Aspects. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020. [DOI: 10.1109/trpms.2019.2935240] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Pollack A, Chinea FM, Bossart E, Kwon D, Abramowitz MC, Lynne C, Jorda M, Marples B, Patel VN, Wu X, Reis I, Studenski MT, Casillas J, Stoyanova R. Phase I Trial of MRI-Guided Prostate Cancer Lattice Extreme Ablative Dose (LEAD) Boost Radiation Therapy. Int J Radiat Oncol Biol Phys 2020; 107:305-315. [PMID: 32084522 DOI: 10.1016/j.ijrobp.2020.01.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 01/23/2020] [Accepted: 01/31/2020] [Indexed: 01/04/2023]
Abstract
PURPOSE A phase I clinical trial was designed to test the feasibility and toxicity of administering high-dose spatially fractionated radiation therapy to magnetic resonance imaging (MRI)-defined prostate tumor volumes, in addition to standard treatment. METHODS AND MATERIALS We enrolled 25 men with favorable to high-risk prostate cancer and 1 to 3 suspicious multiparametric MRI (mpMRI) gross tumor volumes (GTVs). The mpMRI-GTVs were treated on day 1 with 12 to 14 Gy via dose cylinders using a lattice extreme ablative dose technique. The entire prostate, along with the proximal seminal vesicles, was then treated to 76 Gy at 2 Gy/fraction. For some high-risk patients, the distal seminal vesicles and pelvic lymph nodes received 56 Gy at 1.47 Gy/fraction concurrently in 38 fractions. The total dose to the lattice extreme ablative dose cylinder volume(s) was 88 to 90 Gy (112-123 Gy in 2.0 Gy equivalents, assuming an α-to-β ratio of 3). RESULTS Dosimetric parameters were satisfactorily met. Median follow-up was 66 months. There were no grade 3 acute/subacute genitourinary or gastrointestinal adverse events. Maximum late genitourinary toxicity was grade 1 in 15 (60%), grade 2 in 4 (16%), and grade 4 in 1 (4%; sepsis after a posttreatment transurethral resection). Maximum late gastrointestinal toxicity was grade 1 in 11 (44%) and grade 2 in 4 (16%). Two patients experienced biochemical failure. CONCLUSIONS External beam radiation therapy delivered with an upfront spatially fractionated, stereotactic high-dose mpMRI-GTV boost is feasible and was not associated with any unexpected events. The technique is now part of a follow-up phase II randomized trial.
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Affiliation(s)
- Alan Pollack
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida.
| | - Felix M Chinea
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Elizabeth Bossart
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Deukwoo Kwon
- Departments of Public Health Sciences and Biostatistics and Bioinformatics Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida
| | - Matthew C Abramowitz
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Charles Lynne
- Departments of Urology, University of Miami Miller School of Medicine, Miami, Florida
| | - Merce Jorda
- Departments of Pathology, University of Miami Miller School of Medicine, Miami, Florida
| | - Brian Marples
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Vivek N Patel
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Xiaodong Wu
- Biophysics Research Institute of America, Miami, Florida
| | - Isildinha Reis
- Departments of Public Health Sciences and Biostatistics and Bioinformatics Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida
| | - Matthew T Studenski
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
| | - Javier Casillas
- Department of Radiology, University of Miami, Miller School of Medicine, Miami, Florida
| | - Radka Stoyanova
- Departments of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida
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22
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Yan W, Khan MK, Wu X, Simone CB, Fan J, Gressen E, Zhang X, Limoli CL, Bahig H, Tubin S, Mourad WF. Spatially fractionated radiation therapy: History, present and the future. Clin Transl Radiat Oncol 2020; 20:30-38. [PMID: 31768424 PMCID: PMC6872856 DOI: 10.1016/j.ctro.2019.10.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 12/30/2022] Open
Affiliation(s)
- Weisi Yan
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Mohammad K. Khan
- Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | | | - Charles B. Simone
- New York Proton Center, Department of Radiation Oncology, New York, NY, USA
| | - Jiajin Fan
- Radiation Oncology, Inova Schar Cancer Institute, Inova Health System, USA
| | - Eric Gressen
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Xin Zhang
- Boston University School of Medicine, Boston, MA, USA
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Ivine 92697-2695, USA
| | - Houda Bahig
- Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Slavisa Tubin
- KABEG Klinikum Klagenfurt, Institute of Radiation Oncology, Feschnigstraße 11, 9020 Klagenfurt am Wörthersee, Austria
| | - Waleed F. Mourad
- Department of Radiation Medicine, Markey Cancer Center, University of Kentucky – College of Medicine, USA
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23
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Mohiuddin M, Lynch C, Gao M, Hartsell W. Early clinical results of proton spatially fractionated GRID radiation therapy (SFGRT). Br J Radiol 2019; 93:20190572. [PMID: 31651185 DOI: 10.1259/bjr.20190572] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Approximately 70 patients with large and bulky tumors refractory to prior treatments were treated with photon spatially fractionated GRID radiation (SFGRT). We identified 10 additional patients who clinically needed GRID but could not be treated with photons due to adjacent critical organs. We developed a proton SFGRT technique, and we report treatment of these 10 patients. METHODS Subject data were reviewed for clinical results and dosimetric data. 50% of the patients were metastatic at the time of treatment and five had previous photon radiation to the local site but not via GRID. They were treated with 15-20 cobalt Gray equivalent using a single proton GRID field with an average beamlet count of 22.6 (range 7-51). 80% received an average adjuvant radiation dose to the GRID region of 40.8Gy (range 13.7-63.8Gy). Four received subsequent systemic therapy. RESULTS The median follow-up time was 5.9 months (1.1-18.9). At last follow-up, seven patients were alive and three had died. Two patients who had died from metastatic disease had local shrinkage of tumor. Of those alive, four had complete or partial response, two had partial response but later progressed, and one had no response. For all patients, the tumor regression/local symptom improvement rate was 80%. 50% had acute side-effects of grade1/2 only and all were well-tolerated. CONCLUSION In circumstances where patients cannot receive photon GRID, proton SFGRT is clinically feasible and effective, with a similar side-effect profile. ADVANCES IN KNOWLEDGE Proton GRID should be considered as a treatment option earlier in the disease course for patients who cannot be treated by photon GRID.
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Affiliation(s)
- Majid Mohiuddin
- Northwestern Medicine Chicago Proton Center 4455 Weaver Pkwy, Warrenville, IL 60555.,Radiation Oncology Consultants, Ltd. 700 Commerce Drive, Suite 500, Oak Brook, IL 60523
| | - Connor Lynch
- Northwestern Medicine Chicago Proton Center 4455 Weaver Pkwy, Warrenville, IL 60555
| | - Mingcheng Gao
- Northwestern Medicine Chicago Proton Center 4455 Weaver Pkwy, Warrenville, IL 60555
| | - William Hartsell
- Northwestern Medicine Chicago Proton Center 4455 Weaver Pkwy, Warrenville, IL 60555.,Radiation Oncology Consultants, Ltd. 700 Commerce Drive, Suite 500, Oak Brook, IL 60523
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24
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De Marzi L, Nauraye C, Lansonneur P, Pouzoulet F, Patriarca A, Schneider T, Guardiola C, Mammar H, Dendale R, Prezado Y. Spatial fractionation of the dose in proton therapy: Proton minibeam radiation therapy. Cancer Radiother 2019; 23:677-681. [DOI: 10.1016/j.canrad.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/01/2019] [Indexed: 10/26/2022]
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25
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Nystrom H, Jensen MF, Nystrom PW. Treatment planning for proton therapy: what is needed in the next 10 years? Br J Radiol 2019; 93:20190304. [PMID: 31356107 DOI: 10.1259/bjr.20190304] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Treatment planning is the process where the prescription of the radiation oncologist is translated into a deliverable treatment. With the complexity of contemporary radiotherapy, treatment planning cannot be performed without a computerized treatment planning system. Proton therapy (PT) enables highly conformal treatment plans with a minimum of dose to tissues outside the target volume, but to obtain the most optimal plan for the treatment, there are a multitude of parameters that need to be addressed. In this review areas of ongoing improvements and research in the field of PT treatment planning are identified and discussed. The main focus is on issues of immediate clinical and practical relevance to the PT community highlighting the needs for the near future but also in a longer perspective. We anticipate that the manual tasks performed by treatment planners in the future will involve a high degree of computational thinking, as many issues can be solved much better by e.g. scripting. More accurate and faster dose calculation algorithms are needed, automation for contouring and planning is required and practical tools to handle the variable biological efficiency in PT is urgently demanded just to mention a few of the expected improvements over the coming 10 years.
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Affiliation(s)
- Hakan Nystrom
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.,Skandionkliniken, Uppsala, Sweden
| | | | - Petra Witt Nystrom
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.,Skandionkliniken, Uppsala, Sweden
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26
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Novel treatment planning approaches to enhance the therapeutic ratio: targeting the molecular mechanisms of radiation therapy. Clin Transl Oncol 2019; 22:447-456. [PMID: 31254253 DOI: 10.1007/s12094-019-02165-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/16/2019] [Indexed: 12/16/2022]
Abstract
Radiation acts not only through cell death but has also angiogenic, immunomodulatory and bystander effects. The realization of its systemic implications has led to extensive research on the combination of radiotherapy with systemic treatments, including immunotherapy and antiangiogenic agents. Parameters such as dose, fractionation and sequencing of treatments are key determinants of the outcome. However, recent high-quality research indicates that these are not the only radiation therapy parameters that influence its systemic effect. To effectively integrate systemic agents with radiation therapy, these new aspects of radiation therapy planning will have to be taken into consideration in future clinical trials. Our aim is to review these new treatment planning parameters that can influence the balance between contradicting effects of radiation therapy so as to enhance the therapeutic ratio.
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27
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Meyer J, Eley J, Schmid TE, Combs SE, Dendale R, Prezado Y. Spatially fractionated proton minibeams. Br J Radiol 2019; 92:20180466. [PMID: 30359081 PMCID: PMC6541186 DOI: 10.1259/bjr.20180466] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/11/2018] [Accepted: 10/15/2018] [Indexed: 12/26/2022] Open
Abstract
Extraordinary normal tissue response to highly spatially fractionated X-ray beams has been explored for over 25 years. More recently, alternative radiation sources have been developed and utilized with the aim to evoke comparable effects. These include protons, which lend themselves well for this endeavour due to their physical depth dose characteristics as well as corresponding variable biological effectiveness. This paper addresses the motivation for using protons to generate spatially fractionated beams and reviews the technological implementations and experimental results to date. This includes simulation and feasibility studies, collimation and beam characteristics, dosimetry and biological considerations as well as the results of in vivo and in vitro studies. Experimental results are emerging indicating an extraordinary normal tissue sparing effect analogous to what has been observed for synchrotron generated X-ray microbeams. The potential for translational research and feasibility of spatially modulated proton beams in clinical settings is discussed.
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Affiliation(s)
- Juergen Meyer
- Department of Radiation Oncology, University of Washington, Seattle, WA, USA
| | - John Eley
- Department of Radiation Oncology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | | | | | - Remi Dendale
- Institut Curie, Centre de Protonthérapie d’Orsay, Orsay, France
| | - Yolanda Prezado
- Laboratoire d'Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), Centre National de la Recherche Scientifique, Universités Paris 11 and Paris 7, Campus d'Orsay, Orsay, France
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28
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Henry T, Ödén J. Interlaced proton grid therapy – Linear energy transfer and relative biological effectiveness distributions. Phys Med 2018; 56:81-89. [DOI: 10.1016/j.ejmp.2018.10.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/03/2018] [Accepted: 10/30/2018] [Indexed: 12/25/2022] Open
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