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Misa J, Volk A, Bernard ME, Clair WS, Pokhrel D. Dosimetric impact of intrafraction patient motion on MLC-based 3D-conformal spatially fractionated radiation therapy treatment of large and bulky tumors. J Appl Clin Med Phys 2024:e14469. [PMID: 39031843 DOI: 10.1002/acm2.14469] [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: 04/10/2024] [Revised: 06/19/2024] [Accepted: 06/28/2024] [Indexed: 07/22/2024] Open
Abstract
PURPOSE To evaluate the dosimetric impact on spatially fractionated radiation therapy (SFRT) plan quality due to intrafraction patient motion via multi-field MLC-based method for treating large and bulky (≥8 cm) unresectable tumors. METHODS For large tumors, a cone beam CT-guided 3D conformal MLC-based SFRT method was utilized with 15 Gy prescription. An MLC GTV-fitting algorithm provided 1 cm diameter apertures with a 2 cm center-to-center distance at the isocenter. This generated a highly heterogeneous sieve-like dose distribution within an hour, enabling same-day SFRT treatment. Fifteen previously treated SFRT patients were analyzed (5 head & neck [H&N], 5 chest and lungs, and 5 abdominal and pelvis masses). For each plan, intrafraction motion errors were simulated by incrementally shifting original isocenters of each field in different x-, y-, and z-directions from 1 to 5 mm. The dosimetric metrics analyzed were: peak-to-valley-dose-ratio (PVDR), percentage of GTV receiving 7.5 Gy, GTV mean dose, and maximum dose to organs-at-risk (OARs). RESULTS For ±1, ±2, ±3, ±4, and ±5 mm isocenter shifts: PVDR dropped by 3.9%, 3.8%, 4.0%, 4.1%, and 5.5% on average respectively. The GTV(V7.5) remained within 0.2%, and the GTV mean dose remained within 3.3% on average, compared to the original plans. The average PVDR drop for 5 mm shifts was 4.2% for H&N cases, 10% for chest and lung, and 2.2% for abdominal and pelvis cases. OAR doses also increased. The maximum dose to the spinal cord increased by up to 17 cGy in H&N plans, mean lung dose (MLD) changed was small for chest/lung, but the bowel dose varied up to 100 cGy for abdominal and pelvis cases. CONCLUSION Due to tumor size, location, and characteristics of MLC-based SFRT, isocenter shifts of up to ±5 mm in different directions had moderate effects on PVDR for H&N and pelvic tumors and a larger effect on chest tumors. The dosimetric impact on OAR doses depended on the treatment site. Site-specific patient masks, Vac-Lok bags, and proper immobilization devices similar to SBRT/SRT setups should be used to minimize these effects.
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Affiliation(s)
- Josh Misa
- Department of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA
| | - Alex Volk
- Department of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA
| | - Mark E Bernard
- Department of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA
| | - William St Clair
- Department of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA
| | - Damodar Pokhrel
- Department of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA
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Ahmed MM, Wu X, Mohiuddin M, Perez NC, Zhang H, Amendola BE, Malachowska B, Mohiuddin M, Guha C. Optimizing GRID and Lattice Spatially Fractionated Radiation Therapy: Innovative Strategies for Radioresistant and Bulky Tumor Management. Semin Radiat Oncol 2024; 34:310-322. [PMID: 38880540 DOI: 10.1016/j.semradonc.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Treating radioresistant and bulky tumors is challenging due to their inherent resistance to standard therapies and their large size. GRID and lattice spatially fractionated radiation therapy (simply referred to GRID RT and LRT) offer promising techniques to tackle these issues. Both approaches deliver radiation in a grid-like or lattice pattern, creating high-dose peaks surrounded by low-dose valleys. This pattern enables the destruction of significant portions of the tumor while sparing healthy tissue. GRID RT uses a 2-dimensional pattern of high-dose peaks (15-20 Gy), while LRT delivers a three-dimensional array of high-dose vertices (10-20 Gy) spaced 2-5 cm apart. These techniques are beneficial for treating a variety of cancers, including soft tissue sarcomas, osteosarcomas, renal cell carcinoma, melanoma, gastrointestinal stromal tumors (GISTs), pancreatic cancer, glioblastoma, and hepatocellular carcinoma. The specific grid and lattice patterns must be carefully tailored for each cancer type to maximize the peak-to-valley dose ratio while protecting critical organs and minimizing collateral damage. For gynecologic cancers, the treatment plan should align with the international consensus guidelines, incorporating concurrent chemotherapy for optimal outcomes. Despite the challenges of precise dosimetry and patient selection, GRID RT and LRT can be cost-effective using existing radiation equipment, including particle therapy systems, to deliver targeted high-dose radiation peaks. This phased approach of partial high-dose induction radiation therapy with standard fractionated radiation therapy maximizes immune modulation and tumor control while reducing toxicity. Comprehensive treatment plans using these advanced techniques offer a valuable framework for radiation oncologists, ensuring safe and effective delivery of therapy for radioresistant and bulky tumors. Further clinical trials data and standardized guidelines will refine these strategies, helping expand access to innovative cancer treatments.
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Affiliation(s)
- Mansoor M Ahmed
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY.
| | - Xiaodong Wu
- Executive Medical Physics Associates, Miami, FL
| | - Majid Mohiuddin
- Radiation Oncology Consultants and Northwestern Proton Center, Warrenville, IL
| | | | - Hualin Zhang
- Department of Radiation Oncology, University of Southern California, Los Angeles, CA
| | | | - Beata Malachowska
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY
| | | | - Chandan Guha
- Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY
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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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Das IJ, Khan AU, Dogan SK, Longo M. Grid/lattice therapy: consideration of small field dosimetry. Br J Radiol 2024; 97:1088-1098. [PMID: 38552328 PMCID: PMC11135801 DOI: 10.1093/bjr/tqae060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 05/31/2024] Open
Abstract
Small-field dosimetry used in special procedures such as gamma knife, Cyberknife, Tomotherapy, IMRT, and VMAT has been in evolution after several radiation incidences with very significant (70%) errors due to poor understanding of the dosimetry. IAEA-TRS-483 and AAPM-TG-155 have provided comprehensive information on small-fields dosimetry in terms of code of practice and relative dosimetry. Data for various detectors and conditions have been elaborated. It turns out that with a suitable detectors dose measurement accuracy can be reasonably (±3%) achieved for 6 MV beams for fields >1×1 cm2. For grid therapy, even though the treatment is performed with small fields created by either customized blocks, multileaf collimator (MLC), or specialized devices, it is multiple small fields that creates combined treatment. Hence understanding the dosimetry in collection of holes of small field is a separate challenge that needs to be addressed. It is more critical to understand the scattering conditions from multiple holes that form the treatment grid fields. Scattering changes the beam energy (softer) and hence dosimetry protocol needs to be properly examined for having suitable dosimetric parameters. In lieu of beam parameter unavailability in physical grid devices, MLC-based forward and inverse planning is an alternative path for bulky tumours. Selection of detectors in small field measurement is critical and it is more critical in mixed beams created by scattering condition. Ramification of small field concept used in grid therapy along with major consideration of scattering condition is explored. Even though this review article is focussed mainly for dosimetry for low-energy megavoltage photon beam (6 MV) but similar procedures could be adopted for high energy beams. To eliminate small field issues, lattice therapy with the help of MLC is a preferrable choice.
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Affiliation(s)
- Indra J Das
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Ahtesham Ullah Khan
- San Bortolo Hospital, Medical Physics Department, Viale F. Rodolfi 37, 36100 Vicenza, Italy
| | - Serpil K Dogan
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Mariaconcetta Longo
- San Bortolo Hospital, Medical Physics Department, Viale F. Rodolfi 37, 36100 Vicenza, Italy
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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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Karimi AH, Das IJ, Chegeni N, Jabbari I, Jafari F, Geraily G. Beam quality and the mystery behind the lower percentage depth dose in grid radiation therapy. Sci Rep 2024; 14:4510. [PMID: 38402259 PMCID: PMC10894234 DOI: 10.1038/s41598-024-55197-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 02/21/2024] [Indexed: 02/26/2024] Open
Abstract
Grid therapy recently has been picking momentum due to favorable outcomes in bulky tumors. This is being termed as Spatially Fractionated Radiation Therapy (SFRT) and lattice therapy. SFRT can be performed with specially designed blocks made with brass or cerrobend with repeated holes or using multi-leaf collimators where dosimetry is uncertain. The dosimetric challenge in grid therapy is the mystery behind the lower percentage depth dose (PDD) in grid fields. The knowledge about the beam quality, indexed by TPR20/10 (Tissue Phantom Ratio), is also necessary for absolute dosimetry of grid fields. Since the grid may change the quality of the primary photons, a new [Formula: see text] should be evaluated for absolute dosimetry of grid fields. A Monte Carlo (MC) approach is provided to resolving the dosimetric issues. Using 6 MV beam from a linear accelerator, MC simulation was performed using MCNPX code. Additionally, a commercial grid therapy device was used to simulate the grid fields. Beam parameters were validated with MC model for output factor, depth of maximum dose, PDDs, dose profiles, and TPR20/10. The electron and photon spectra were also compared between open and grid fields. The dmax is the same for open and grid fields. The PDD with grid is lower (~ 10%) than the open field. The difference in TPR20/10 of open and grid fields is observable (~ 5%). Accordingly, TPR20/10 is still a good index for the beam quality in grid fields and consequently choose the correct [Formula: see text] in measurements. The output factors for grid fields are 0.2 lower compared to open fields. The lower depth dose with grid therapy is due to lower depth fluence with scatter radiation but it does not impact the dosimetry as the calibration parameters are insensitive to the effective beam energies. Thus, standard dosimetry in open beam based on international protocol could be used.
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Affiliation(s)
- Amir Hossein Karimi
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Radiation Oncology Department, Cancer Institute, Imam-Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Indra J Das
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Nahid Chegeni
- Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Iraj Jabbari
- Department of Nuclear Engineering, Faculty of Physics, University of Isfahan, Isfahan, Iran
| | - Fatemeh Jafari
- Radiation Oncology Department, Cancer Institute, Imam-Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghazale Geraily
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
- Radiation Oncology Department, Cancer Institute, Imam-Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
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At B, Velayudham R. Assessing dosimetric advancements in spatially fractionated radiotherapy: From grids to lattices. Med Dosim 2024:S0958-3947(23)00116-4. [PMID: 38290896 DOI: 10.1016/j.meddos.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/05/2023] [Accepted: 12/21/2023] [Indexed: 02/01/2024]
Abstract
Spatially fractionated radiotherapy (SFRT) techniques have undergone transformative evolution, encompassing physical GRID therapy, MLC-based grids, virtual TOMO GRIDs, and 3-dimensional high-dose lattices. Historical roots trace back to Alban Köhler's pioneering Spatially fractionated grid therapy (SFGRT), utilizing physical grids for dose modulation. Technological innovations introduced multi-leaf collimators (MLCs), enabling adaptable spatial fractionation and a shift to the broader term "SFRT." Physics and dosimetry-based studies have demonstrated the feasibility of computerized treatment planning and identified the potential to minimize the peripheral dose while using such high-dose therapy. Meanwhile, 3-dimensional high-dose lattices showed enhanced precision. The meticulous placement of high-dose volumetric spheres enables a reduction in the volume of high-dose spills. Advancements in 3-dimensional lattices through intensity-modulated radiotherapy and volumetric modulated arc therapy (VMAT) techniques offer enhanced therapeutic options. A database of SFRT studies identified 723 articles. This review shows the trajectory of SFRT from traditional grids to MLC-based approaches, virtual TOMO GRIDs, and innovative 3-dimensional lattices. Technological innovations, dosimetric advancements, and clinical feasibility have underscored the continual progress in refining spatially fractionated radiotherapy. The integration of MLCs and lattice techniques has demonstrated improved therapeutic outcomes, solidifying their relevance in modern radiation therapy protocols. Research has yet to reveal a clear correlation between treatment outcomes and dosimetric parameters. Additional investigations are necessary to assess the impact of various dosimetric parameters, such as EUD, peak-to-valley ratio (PVDR), D5%, D10%, D20%, D90%, etc., on the effectiveness of treatments.
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Affiliation(s)
- Bhagyalakshmi At
- Vellore Institute of Technology, Vellore Campus, Katpadi, Tamil Nadu 500036, India; American Oncology Institute at Baby Memorial Hospital, Kozhikode, Kerala 673004, India
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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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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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10
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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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11
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Cahoon P, Giacometti V, Casey F, Russell E, McGarry C, Prise KM, McMahon SJ. Investigating spatial fractionation and radiation induced bystander effects: a mathematical modelling approach. Phys Med Biol 2021; 66. [PMID: 34666318 DOI: 10.1088/1361-6560/ac3119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 10/19/2021] [Indexed: 11/12/2022]
Abstract
Radiation induced bystander effects (RIBEs) have been shown to cause death in cells receiving little or no physical dose. In standard radiotherapy, where uniform fields are delivered and all cells are directly exposed to radiation, this phenomenon can be neglected. However, the role of RIBEs may become more influential when heterogeneous fields are considered. Mathematical modelling can be used to determine how these heterogeneous fields might influence cell survival, but most established techniques account only for the direct effects of radiation. To gain a full appreciation of how non-uniform fields impact cell survival, it is also necessary to consider the indirect effects of radiation. In this work, we utilise a mathematical model that accounts for both the direct effects of radiation on cells and RIBEs. This model is used to investigate how spatially fractionated radiotherapy plans impact cell survivalin vitro. These predictions were compared to survival in normal and cancerous cells following exposure to spatially fractionated plans using a clinical linac. The model is also used to explore how spatially fractionated radiotherapy will impact tumour controlin vivo. Results suggest that spatially fractionated plans are associated with higher equivalent uniform doses than conventional uniform plans at clinically relevant doses. The model predicted only small changes changes in normal tissue complication probability, compared to the larger protection seen clinically. This contradicts a central paradigm of radiotherapy where uniform fields are assumed to maximise cell kill and may be important for future radiotherapy optimisation.
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Affiliation(s)
- Paul Cahoon
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Valentina Giacometti
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.,Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, Northern Ireland, United Kingdom
| | - Francis Casey
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, Northern Ireland, United Kingdom.,Nottingham Radiotherapy Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Emily Russell
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Conor McGarry
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.,Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, Northern Ireland, United Kingdom
| | - Kevin M Prise
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Stephen J McMahon
- Patrick G Johnson Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
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12
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Saglam Y, Bolukbasi Y, Atasoy AI, Karakose F, Budak M, Alpan V, Topkan E, Selek U. Novel Clinically Weight-Optimized Dynamic Conformal Arcs (WO-DCA) for Liver SBRT: A Comparison with Volumetric Modulated Arc Therapy (VMAT). Ther Clin Risk Manag 2021; 17:1053-1064. [PMID: 34611405 PMCID: PMC8487279 DOI: 10.2147/tcrm.s328375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/11/2021] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To evaluate the feasibility of shortening the duration of liver stereotactic radiotherapy (SBRT) without jeopardizing dosimetry or conformity by utilizing weight-optimized dynamic conformal arcs (WO-DCA) as opposed to volumetric modulated arc therapy (VMAT) for tumors away from critical structures. METHODS Nineteen patients with liver metastasis were included, previously treated with 50 Gy in 4 fractions with VMAT technique using two partial coplanar arcs of 6 MV beams delivered in high-definition multi-leaf collimator (HD-MLC). Two coplanar partial WO-DCA were generated on Pinnacle treatment planning system (TPS) for each patient; and MLC aperture around the planning target volume (PTV) was automatically generated at different margins for both arcs and maintained dynamically around the target during arc rotation. Weight of the two arcs using optimization method was adjusted between the arcs to maximize tumor coverage and protect organs at risk (OAR) based on the RTOG-0438 protocol. RESULTS The WO-DCA plans successfully "agreed" with the standard VMAT for OAR (liver, spinal cord, stomach, duodenum, small bowel, and heart) and PTV (Dmean, D98%, D2%, CI, and GI), with superior mean quality assurance (QA) pass rate (97.06 vs 93.00 for VMAT; P < 0.001 and t = 8.87). Similarly, the WO-DCA technique additionally reduced the beam-on time (3.26 vs 4.43; P < 0.001) and monitor unit (1860 vs 2705 for VMAT; P < 0.001) values significantly. CONCLUSION The WO-DCA plans might minimize small-field dosimetry errors and defeat patient-specific VMAT QA requirements due to the omission of MLC beam modulation through the target volume. The WO-DCA plans may additionally enable faster treatment delivery times and lower OAR without sacrificing target doses in SBRT of liver tumors away from critical structures.
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Affiliation(s)
- Yucel Saglam
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
- UT MD Anderson Radiation Oncology Outreach Center at American Hospital, Istanbul, Turkey
| | - Yasemin Bolukbasi
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
- UT MD Anderson Radiation Oncology Outreach Center at American Hospital, Istanbul, Turkey
- University of Texas, MD Anderson Cancer Center, Department of Radiation Oncology, Houston, TX, USA
| | - Ali Ihsan Atasoy
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
| | - Fatih Karakose
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
| | - Mustafa Budak
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
| | - Vildan Alpan
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
- UT MD Anderson Radiation Oncology Outreach Center at American Hospital, Istanbul, Turkey
| | - Erkan Topkan
- Baskent University Medical Faculty, Department of Radiation Oncology, Adana, Turkey
| | - Ugur Selek
- Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
- UT MD Anderson Radiation Oncology Outreach Center at American Hospital, Istanbul, Turkey
- University of Texas, MD Anderson Cancer Center, Department of Radiation Oncology, Houston, TX, USA
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13
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Ferini G, Valenti V, Tripoli A, Illari SI, Molino L, Parisi S, Cacciola A, Lillo S, Giuffrida D, Pergolizzi S. Lattice or Oxygen-Guided Radiotherapy: What If They Converge? Possible Future Directions in the Era of Immunotherapy. Cancers (Basel) 2021; 13:cancers13133290. [PMID: 34209192 PMCID: PMC8268715 DOI: 10.3390/cancers13133290] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 12/31/2022] Open
Abstract
Palliative radiotherapy has a great role in the treatment of large tumor masses. However, treating a bulky disease could be difficult, especially in critical anatomical areas. In daily clinical practice, short course hypofractionated radiotherapy is delivered in order to control the symptomatic disease. Radiation fields generally encompass the entire tumor mass, which is homogeneously irradiated. Recent technological advances enable delivering a higher radiation dose in small areas within a large mass. This goal, previously achieved thanks to the GRID approach, is now achievable using the newest concept of LATTICE radiotherapy (LT-RT). This kind of treatment allows exploiting various radiation effects, such as bystander and abscopal effects. These events may be enhanced by the concomitant use of immunotherapy, with the latter being ever more successfully delivered in cancer patients. Moreover, a critical issue in the treatment of large masses is the inhomogeneous intratumoral distribution of well-oxygenated and hypo-oxygenated areas. It is well known that hypoxic areas are more resistant to the killing effect of radiation, hence the need to target them with higher aggressive doses. This concept introduces the "oxygen-guided radiation therapy" (OGRT), which means looking for suitable hypoxic markers to implement in PET/CT and Magnetic Resonance Imaging. Future treatment strategies are likely to involve combinations of LT-RT, OGRT, and immunotherapy. In this paper, we review the radiobiological rationale behind a potential benefit of LT-RT and OGRT, and we summarize the results reported in the few clinical trials published so far regarding these issues. Lastly, we suggest what future perspectives may emerge by combining immunotherapy with LT-RT/OGRT.
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Affiliation(s)
- Gianluca Ferini
- REM Radioterapia, Viagrande, I-95029 Catania, Italy; (V.V.); (A.T.)
- Correspondence: ; Tel.: +39-095-789-4581
| | - Vito Valenti
- REM Radioterapia, Viagrande, I-95029 Catania, Italy; (V.V.); (A.T.)
| | | | | | - Laura Molino
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università di Messina, I-98100 Messina, Italy; (L.M.); (S.P.); (A.C.); (S.L.); (S.P.)
| | - Silvana Parisi
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università di Messina, I-98100 Messina, Italy; (L.M.); (S.P.); (A.C.); (S.L.); (S.P.)
| | - Alberto Cacciola
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università di Messina, I-98100 Messina, Italy; (L.M.); (S.P.); (A.C.); (S.L.); (S.P.)
| | - Sara Lillo
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università di Messina, I-98100 Messina, Italy; (L.M.); (S.P.); (A.C.); (S.L.); (S.P.)
| | - Dario Giuffrida
- Medical Oncology Unit, Mediterranean Institute of Oncology, Viagrande, I-95029 Catania, Italy;
| | - Stefano Pergolizzi
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università di Messina, I-98100 Messina, Italy; (L.M.); (S.P.); (A.C.); (S.L.); (S.P.)
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14
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Cozzi L, Beriwal S, Kuusela E, Chopra S, Burger H, Joubert N, Fogliata A, Agarwal JP, Kupelian P. A novel external beam radiotherapy method for cervical cancer patients using virtual straight or bending boost areas; an in-silico feasibility study. Radiat Oncol 2021; 16:110. [PMID: 34127013 PMCID: PMC8201836 DOI: 10.1186/s13014-021-01838-x] [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: 04/09/2021] [Accepted: 06/10/2021] [Indexed: 12/09/2022] Open
Abstract
Aim To investigate the potential role of a novel spatially fractionated radiation therapy (SFRT) method where heterogeneous dose patterns are created in target areas with virtual rods, straight or curving, of variable position, diameter, separation and alignment personalised to a patient’s anatomy. The images chosen for this study were CT scans acquired for the external beam part of radiotherapy. Methods Ten patients with locally advanced cervical cancer were retrospectively investigated with SFRT. The dose prescription was 30 Gy in 5 fractions to 90% target volume coverage. Peak-and-valley (SFRT_1) and peak-only (SFRT_2) strategies were applied to generate the heterogeneous dose distributions. The planning objectives for the target (CTV) were D90% ≥ 30 Gy, V45Gy ≥ 50–55% and V60Gy ≥ 30%. The planning objectives for the organs at risk (OAR) were: D2cm3 ≤ 23.75 Gy, 17.0 Gy, 19.5 Gy, 17.0 Gy for the bladder, rectum, sigmoid and bowel, respectively. The plan comparison was performed employing the quantitative analysis of the dose-volume histograms. Results The D2cm3 was 22.4 ± 2.0 (22.6 ± 2.1) and 13.9 ± 2.9 (13.2 ± 3.0) for the bladder and the rectum for SFRT_1 (SFRT_2). The results for the sigmoid and the bowel were 2.6 ± 3.1 (2.8 ± 3.0) and 9.1 ± 5.9 (9.7 ± 7.3), respectively. The hotspots in the target volume were V45Gy = 43.1 ± 7.5% (56.6 ± 5.6%) and V60Gy = 15.4 ± 5.6% (26.8 ± 6.6%) for SFRT_1 (SFRT_2). To account for potential uncertainties in the positioning, the dose prescription could be escalated to D90% = 33–35 Gy to the CTV without compromising any constraints to the OARs Conclusion In this dosimetric study, the proposed novel planning technique for boosting the cervix uteri was associated with high-quality plans, respecting constraints for the organs at risk and approaching the level of dose heterogeneity achieved with routine brachytherapy. Based on a sample of 10 patients, the results are promising and might lead to a phase I clinical trial. Supplementary Information The online version contains supplementary material available at 10.1186/s13014-021-01838-x.
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Affiliation(s)
- Luca Cozzi
- Radiotherapy and Radiosurgery Department, Humanitas Research Hospital and Cancer Center, Via Manzoni 56, 20089, Milan-Rozzano, Italy. .,Varian Medical Systems, Palo Alto, USA.
| | - Sushil Beriwal
- Department of Radiation Oncology, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Esa Kuusela
- Varian Medical Systems Finland, Helsinki, Finland
| | - Supriya Chopra
- Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Homi Bhaba National Institute, Mumbai, India
| | - Hester Burger
- Division of Medical Physics, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa
| | - Nanette Joubert
- Division of Medical Physics, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa
| | - Antonella Fogliata
- Radiotherapy and Radiosurgery Department, Humanitas Research Hospital and Cancer Center, Via Manzoni 56, 20089, Milan-Rozzano, Italy
| | - Jai Prakash Agarwal
- Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Homi Bhaba National Institute, Mumbai, India
| | - Pat Kupelian
- Varian Medical Systems, Palo Alto, USA.,Radiation Oncology Dept, University of California, Los Angeles, USA
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15
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Murphy NL, Philip R, Wozniak M, Lee BH, Donnelly ED, Zhang H. A simple dosimetric approach to spatially fractionated GRID radiation therapy using the multileaf collimator for treatment of breast cancers in the prone position. J Appl Clin Med Phys 2020; 21:105-114. [PMID: 33119939 PMCID: PMC7700924 DOI: 10.1002/acm2.13040] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 01/06/2023] Open
Abstract
The purpose of this study was to explore the treatment planning methods of spatially fractionated radiation therapy (SFRT), commonly referred to as GRID therapy, in the treatment of breast cancer patients using multileaf collimator (MLC) in the prone position. A total of 12 patients with either left or right breast cancer were retrospectively chosen. The computed tomography (CT) images taken for the whole breast external beam radiation therapy (WB‐EBRT) were used for GRID therapy planning. Each GRID plan was made by using two portals and each portal had two fields with 1‐cm aperture size. The dose prescription point was placed at the center of the target volume, and a dose of 20 Gy with 6‐MV beams was prescribed. Dose‐volume histogram (DVH) curves were generated to evaluate dosimetric properties. A modified linear‐quadratic (MLQ) radiobiological response model was used to assess the equivalent uniform doses (EUD) and therapeutic ratios (TRs) of all GRID plans. The DVH curves indicated that these MLC‐based GRID therapy plans can deliver heterogeneous dose distribution in the target volume as seen with the conventional cerrobend GRID block. The plans generated by the MLC technique also demonstrated the advantage for accommodating different target shapes, sparing normal structures, and reporting dose metrics to the targets and the organs at risks. All GRID plans showed to have similar dosimetric parameters, implying the plans can be made in a consistent quality regardless of the shape of the target and the size of volume. The mean dose of lung and heart were respectively below 0.6 and 0.7 Gy. When the size of aperture is increased from 1 to 2 cm, the EUD and TR became smaller, but the peak/valley dose ratio (PVDR) became greater. The dosimetric approach of this study was proven to be simple, practical and easy to be implemented in clinic.
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Affiliation(s)
- Natasha L Murphy
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Rino Philip
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Matt Wozniak
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Brian H Lee
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Eric D Donnelly
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Hualin Zhang
- Department of Radiation Oncology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
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