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Karger CP, Elter A, Dorsch S, Mann P, Pappas E, Oldham M. Validation of complex radiotherapy techniques using polymer gel dosimetry. Phys Med Biol 2024; 69:06TR01. [PMID: 38330494 DOI: 10.1088/1361-6560/ad278f] [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: 02/06/2023] [Accepted: 02/08/2024] [Indexed: 02/10/2024]
Abstract
Modern radiotherapy delivers highly conformal dose distributions to irregularly shaped target volumes while sparing the surrounding normal tissue. Due to the complex planning and delivery techniques, dose verification and validation of the whole treatment workflow by end-to-end tests became much more important and polymer gel dosimeters are one of the few possibilities to capture the delivered dose distribution in 3D. The basic principles and formulations of gel dosimetry and its evaluation methods are described and the available studies validating device-specific geometrical parameters as well as the dose delivery by advanced radiotherapy techniques, such as 3D-CRT/IMRT and stereotactic radiosurgery treatments, the treatment of moving targets, online-adaptive magnetic resonance-guided radiotherapy as well as proton and ion beam treatments, are reviewed. The present status and limitations as well as future challenges of polymer gel dosimetry for the validation of complex radiotherapy techniques are discussed.
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Affiliation(s)
- Christian P Karger
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Alina Elter
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
- Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany
| | - Stefan Dorsch
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Philipp Mann
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Evangelos Pappas
- Radiology & Radiotherapy Sector, Department of Biomedical Sciences, University of West Attica, Athens, Greece
| | - Mark Oldham
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
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Khaledi N, Khan R, Gräfe JL. Historical Progress of Stereotactic Radiation Surgery. J Med Phys 2023; 48:312-327. [PMID: 38223793 PMCID: PMC10783188 DOI: 10.4103/jmp.jmp_62_23] [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: 05/04/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 01/16/2024] Open
Abstract
Radiosurgery and stereotactic radiotherapy have established themselves as precise and accurate areas of radiation oncology for the treatment of brain and extracranial lesions. Along with the evolution of other methods of radiotherapy, this type of treatment has been associated with significant advances in terms of a variety of modalities and techniques to improve the accuracy and efficacy of treatment. This paper provides a comprehensive overview of the progress in stereotactic radiosurgery (SRS) over several decades, and includes a review of various articles and research papers, commencing with the emergence of stereotactic techniques in radiotherapy. Key clinical aspects of SRS, such as fixation methods, radiobiology considerations, quality assurance practices, and treatment planning strategies, are presented. In addition, the review highlights the technological advancements in treatment modalities, encompassing the transition from cobalt-based systems to linear accelerator-based modalities. By addressing these topics, this study aims to offer insights into the advancements that have shaped the field of SRS, that have ultimately enhanced the accuracy and effectiveness of treatment.
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Affiliation(s)
- Navid Khaledi
- Department of Medical Physics, Cancer Care Manitoba, Winnipeg, MB, Canada
| | - Rao Khan
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
- Department of Physics and Astronomy and Department of Radiation Oncology, Howard University, Washington, District of Columbia, USA
| | - James L. Gräfe
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
- Cancer Care Program, Dr. H. Bliss Murphy Cancer Center. 300 Prince Philip Drive St. John’s, NL, Canada
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Faccenda V, Panizza D, Pisoni V, Trivellato S, Daniotti MC, Bianchi SP, De Ponti E, Arcangeli S. Single-Isocenter Linac-Based Radiosurgery for Brain Metastases with Coplanar Arcs: A Dosimetric and Clinical Analysis. Cancers (Basel) 2023; 15:4496. [PMID: 37760466 PMCID: PMC10526167 DOI: 10.3390/cancers15184496] [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: 07/11/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
The efficacy of linac-based SRS/fSRS treatments using the single-isocenter coplanar FFF-VMAT technique for both single and multiple BM was investigated. Seventy patients (129 BM) treated with 15-21 Gy in 1 (n = 59) or 27 Gy in 3 (n = 11) fractions were analyzed. For each fraction, plans involving the intra-fractional errors measured by post-treatment CBCT were recalculated. The relationships of BM size, distance-to-isocenter, and barycenter shift with the difference in target coverage were evaluated. Clinical outcomes were assessed using logistic regression and Kaplan-Meier analysis. The median delivery time was 3.78 min (range, 1.83-9.25). The median post-treatment 3D error was 0.5 mm (range, 0.1-2.7) and the maximum rotational error was 0.3° (range, 0.0-1.3). In single BM patients, the GTV D95% was never reduced by >5%, whereas PTV D95% reductions >1% occurred in only 11 cases (29%). In multiple BM patients, dose deficits >5% and >1% occurred in 2 GTV (2%) and 34 PTV (37%), respectively. The differences in target coverage showed a moderate-to-strong correlation only with barycenter shift. Local failure of at least one treated BM occurred in 13 (21%) patients and the 1-year and 2-year local control rates for all lesions were 94% and 90%, respectively. The implemented workflow ensured that the degradation of target and brain dose metrics in delivered treatments was negligible. Along with encouraging clinical outcomes, these findings warrant a reduction in the PTV margins at our institution.
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Affiliation(s)
- Valeria Faccenda
- Medical Physics Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy; (V.F.); (D.P.); (S.T.); (M.C.D.); (E.D.P.)
| | - Denis Panizza
- Medical Physics Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy; (V.F.); (D.P.); (S.T.); (M.C.D.); (E.D.P.)
- School of Medicine and Surgery, University of Milan Bicocca, 20126 Milan, Italy;
| | - Valerio Pisoni
- Radiation Oncology Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy;
| | - Sara Trivellato
- Medical Physics Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy; (V.F.); (D.P.); (S.T.); (M.C.D.); (E.D.P.)
| | - Martina Camilla Daniotti
- Medical Physics Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy; (V.F.); (D.P.); (S.T.); (M.C.D.); (E.D.P.)
| | - Sofia Paola Bianchi
- School of Medicine and Surgery, University of Milan Bicocca, 20126 Milan, Italy;
| | - Elena De Ponti
- Medical Physics Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy; (V.F.); (D.P.); (S.T.); (M.C.D.); (E.D.P.)
- School of Medicine and Surgery, University of Milan Bicocca, 20126 Milan, Italy;
| | - Stefano Arcangeli
- School of Medicine and Surgery, University of Milan Bicocca, 20126 Milan, Italy;
- Radiation Oncology Department, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy;
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Grishchuk D, Dimitriadis A, Sahgal A, De Salles A, Fariselli L, Kotecha R, Levivier M, Ma L, Pollock BE, Regis J, Sheehan J, Suh J, Yomo S, Paddick I. ISRS Technical Guidelines for Stereotactic Radiosurgery: Treatment of Small Brain Metastases (≤1 cm in Diameter). Pract Radiat Oncol 2022; 13:183-194. [PMID: 36435388 DOI: 10.1016/j.prro.2022.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE The objective of this literature review was to develop International Stereotactic Radiosurgery Society (ISRS) consensus technical guidelines for the treatment of small, ≤1 cm in maximal diameter, intracranial metastases with stereotactic radiosurgery. Although different stereotactic radiosurgery technologies are available, most of them have similar treatment workflows and common technical challenges that are described. METHODS AND MATERIALS A systematic review of the literature published between 2009 and 2020 was performed in Pubmed using the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) methodology. The search terms were limited to those related to radiosurgery of brain metastases and to publications in the English language. RESULTS From 484 collected abstract 37 articles were included into the detailed review and bibliographic analysis. An additional 44 papers were identified as relevant from a search of the references. The 81 papers, including additional 7 international guidelines, were deemed relevant to at least one of five areas that were considered paramount for this report. These areas of technical focus have been employed to structure these guidelines: imaging specifications, target volume delineation and localization practices, use of margins, treatment planning techniques, and patient positioning. CONCLUSION This systematic review has demonstrated that Stereotactic Radiosurgery (SRS) for small (1 cm) brain metastases can be safely performed on both Gamma Knife (GK) and CyberKnife (CK) as well as on modern LINACs, specifically tailored for radiosurgical procedures, However, considerable expertise and resources are required for a program based on the latest evidence for best practice.
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Affiliation(s)
- Diana Grishchuk
- National Hospital for Neurology and Neurosurgery, London, United Kingdom.
| | - Alexis Dimitriadis
- National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada
| | - Antonio De Salles
- Department of Neurosurgery, University of California, Los Angeles, California
| | - Laura Fariselli
- Radiotherapy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta Milano, Unita di Radiotherapia, Milan, Italy
| | - Rupesh Kotecha
- Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, Florida
| | - Marc Levivier
- Neurosurgery Service and Gamma Knife Center, Center Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Lijun Ma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California
| | - Bruce E Pollock
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Jean Regis
- Department of Functional Neurosurgery, La Timone Hospital, Aix-Marseille University, Marseille, France
| | - Jason Sheehan
- Department of Neurologic Surgery, University of Virginia, Charlottesville, Virginia
| | - John Suh
- Department of Radiation Oncology, Cleveland Clinic, Cleveland, Ohio
| | - Shoji Yomo
- Division of Radiation Oncology, Aizawa Comprehensive Cancer Center, Aizawa Hospital, Matsumoto, Japan
| | - Ian Paddick
- National Hospital for Neurology and Neurosurgery, London, United Kingdom
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Farahani S, Mosleh-Shirazi MA, Riyahi Alam N, Rabi Mahdavi S, Raeisi F. Global and spatial dosimetric characteristics of N-vinylpyrrolidone-based polymer gel dosimeters as a function of medium-term post-preparation and post-irradiation time. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bry V, Saenz D, Pappas E, Kalaitzakis G, Papanikolaou N, Rasmussen K. End to end comparison of surface-guided imaging versus stereoscopic X-rays for the SRS treatment of multiple metastases with a single isocenter using 3D anthropomorphic gel phantoms. J Appl Clin Med Phys 2022; 23:e13576. [PMID: 35322526 PMCID: PMC9121024 DOI: 10.1002/acm2.13576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/10/2022] [Accepted: 02/12/2022] [Indexed: 01/03/2023] Open
Abstract
INTRODUCTION Two end-to-end tests evaluate the accuracy of a surface-guided radiation therapy (SGRT) system (CRAD Catalyst HD) for position verification in comparison to a stereoscopic x-ray imaging system (Brainlab Exactrac ) for single-isocenter, multiple metastases stereotactic radiosurgery (SRS) using 3D polymer gel inserts. MATERIALS AND METHODS A 3D-printed phantom (Prime phantom, RTsafe PC, Athens, Greece) with two separate cylindrical polymer gel inserts were immobilized in open-face masks and treated with a single isocentric, multitarget SRS plan. Planning was done in Brainlab (Elements) to treat five metastatic lesions in one fraction, and initial setup was done using cone beam computed tomography. Positional verification was done using orthogonal X-ray imaging (Brainlab Exactrac) and/or a surface imaging system (CRAD Catalyst HD, Uppsala, Sweden), and shift discrepancies were recorded for each couch angle. Forty-two hours after irradiation, the gel phantom was scanned in a 1.5 Tesla MRI, and images were fused with the patient computed tomography data/structure set for further analysis of spatial dose distribution. RESULTS Discrepancies between the CRAD Catalyst HD system and Brainlab Exactrac were <1 mm in the translational direction and <0.5° in the angular direction at noncoplanar couch angles. Dose parameters (DMean% , D95% ) and 3D gamma index passing rates were evaluated for both setup modalities for each planned target volume (PTV) at a variety of thresholds: 3%/2 mm (Exactrac≥93.1% and CRAD ≥87.2%), 5%/2 mm (Exactrac≥95.6% and CRAD ≥94.6%), and 5%/1 mm (Exactrac≥81.8% and CRAD ≥83.7%). CONCLUSION Dose metrics for a setup with surface imaging was found to be consistent with setup using x-ray imaging, demonstrating high accuracy and reproducibility for treatment delivery. Results indicate the feasibility of using surface imaging for position verification at noncoplanar couch angles for single-isocenter, multiple-target SRS using end-to-end quality assurance (QA) testing with 3D polymer gel dosimetry.
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Affiliation(s)
- Victoria Bry
- Department of Radiation OncologyThe University of Texas Health at San AntonioSan AntonioTexasUSA
| | - Daniel Saenz
- Department of Radiation OncologyThe University of Texas Health at San AntonioSan AntonioTexasUSA
| | - Evangelos Pappas
- Department of Biomedical SciencesRadiology and Radiotherapy SectorUniversity of West AtticaAthensGreece
| | | | - Nikos Papanikolaou
- Department of Radiation OncologyThe University of Texas Health at San AntonioSan AntonioTexasUSA
| | - Karl Rasmussen
- Department of Radiation OncologyThe University of Texas Health at San AntonioSan AntonioTexasUSA
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Durmus IF, Okumus A. Dosimetric comparison of mDCAT and VMAT techniques according to 6MV-FFF and 10MV-FFF energies in patients with single adrenal metastasis. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2022; 30:1023-1032. [PMID: 35848004 DOI: 10.3233/xst-221192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
OBJECTIVE To compare dosimetric and radiobiological terms of modified dynamic conformal arc therapy (mDCAT) and volumetric modulated arc therapy (VMAT) techniques using different flattening-filter free (FFF) energies in patients with single adrenal metastasis. METHODS In this study, plans were prepared for 10 patients drawing on the mDCAT and VMAT techniques with 6MV-FFF and 10MV-FFF energies. Target volume doses, biological effective doses (BED), quality indices, Monitor Unit (MU), number of segments, beam-on time and critical organ doses were compared in the plans. RESULTS Plans with the significantly lower gradient index (GI) and conformity index (CI) values were obtained with 6MV-FFF energy VMAT planning (p < 0.05). The higher values were obtained for dose to 95% of internal target volume (ITVD95), ITVD95-BED10 with 10MV-FFF energy VMAT planning, whereas lower results were obtained for high dose spillage (HDS%) values (p < 0,05). With 10MV-FFF energy, HDS% values were 21.1% lower in VMAT plans and 5.6% lower in mDCAT plans compared to 6MV-FFF energy. Plans with approximately 50% fewer segments were obtained in mDCAT plans than VMAT plans (p < 0,05). Beam-on time values with mDCAT was 1.84 times lower when 6MV-FFF energies were analyzed, and 2.11 times lower when 10MV-FFF was analyzed (p < 0,05). Additionally, when 6MV-FFF and 10MV-FFF energies were examined, MU values with mDCAT were 2.1 and 2.5 times lower (p < 0,05). In general, the smaller the target volume size, the greater the differences between MU and beam-on time values mDCAT and VMAT. CONCLUSIONS The study results implied that VMAT enabled to offer significantly more conformal SBRT plans with steeper dose fall-off beyond the target volume for single adrenal metastasis than the mDCAT, which attained at the cost of significantly higher MU and beam-on times. Especially with 10MV-FFF energy mDCAT plans, low-dose-bath zones can be reduced, and shorter-term treatments can be implemented with large segments. In adrenal gland SBRT, higher effective doses can be achieved with the right energy and technique, critical organ doses can be reduced, thus increasing the possibility of local control of the tumor with low toxicity.
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Affiliation(s)
- Ismail Faruk Durmus
- Department of Radiation Oncology, Nisantasi University, Istanbul, Turkey
- Department of Radiation Oncology, Yeni Yuzyil University Gaziosmanpasa Hospital, Istanbul, Turkey
| | - Ayse Okumus
- Department of Radiation Oncology, Nisantasi University, Istanbul, Turkey
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Saenz D, Papanikolaou N, Zoros E, Pappas E, Reiner M, Chew LT, Lim HY, Hancock S, Nebelsky A, Njeh C, Anagnostopoulos G. Robustness of single-isocenter multiple-metastasis stereotactic radiosurgery end-to-end testing across institutions. JOURNAL OF RADIOSURGERY AND SBRT 2021; 7:223-232. [PMID: 33898086 PMCID: PMC8055241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
The accuracy of stereotactic radiosurgery (SRS) to multiple metastases with a single-isocenter using high definition dynamic radiosurgery (HDRS) was evaluated across institutions. An SRS plan was delivered at six HDRS-capable institutions to an anthropomorphic phantom consisting of point, film, and 3D-gel dosimeters. Direct dose comparison and gamma analysis were used to evaluate the accuracy. Point measurements averaged across institutions were within 1.2±0.5%. The average gamma passing rate in the film was 96.6±2.2% (3%/2 mm). For targets within 4 cm of the isocenter, the 3D dosimetric gel gamma passing rate averaged across institutions was >90% (3%/2 mm). The targeting accuracy of high definition dynamic radiosurgery assessed by geometrical offset of the center of dose distributions across multiple institutions in this study was within 1 mm for targets within 4 cm of isocenter. Across variations in clinical practice, comparable dosimetry and localization is possible with this treatment planning and delivery technique.
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Affiliation(s)
- Daniel Saenz
- University of Texas Health Science Center, San Antonio, TX, USA
| | | | - Emmanouil Zoros
- National and Kapodistrian University of Athens Medical School, Athens, Greece
| | | | | | | | | | - Sam Hancock
- Southeast Health, Cape Girardeau, Missouri, USA
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Han EY, Diagaradjane P, Luo D, Ding Y, Kalaitzakis G, Zoros E, Zourari K, Boursianis T, Pappas E, Wen Z, Wang J, Briere TM. Validation of PTV margin for Gamma Knife Icon frameless treatment using a PseudoPatient® Prime anthropomorphic phantom. J Appl Clin Med Phys 2020; 21:278-285. [PMID: 32786141 PMCID: PMC7497928 DOI: 10.1002/acm2.12997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/28/2020] [Accepted: 06/23/2020] [Indexed: 11/09/2022] Open
Abstract
The Gamma Knife Icon allows the treatment of brain tumors mask-based single-fraction or fractionated treatment schemes. In clinic, uniform axial expansion of 1 mm around the gross tumor volume (GTV) and a 1.5 mm expansion in the superior and inferior directions are used to generate the planning target volume (PTV). The purpose of the study was to validate this margin scheme with two clinical scenarios: (a) the patient's head remaining right below the high-definition motion management (HDMM) threshold, and (b) frequent treatment interruptions followed by plan adaptation induced by large pitch head motion. A remote-controlled head assembly was used to control the motion of a PseudoPatient® Prime head phantom; for dosimetric evaluations, an ionization chamber, EBT3 films, and polymer gels were used. These measurements were compared with those from the Gamma Knife plan. For the absolute dose measurements using an ionization chamber, the percentage differences for both targets were less than 3.0% for all scenarios, which was within the expected tolerance. For the film measurements, the two-dimensional (2D) gamma index with a 2%/2 mm criterion showed the passing rates of ≥87% in all scenarios except the scenario 1. The results of Gel measurements showed that GTV (D100 ) was covered by the prescription dose and PTV (D95 ) was well above the planned dose by up to 5.6% and the largest geometric PTV offset was 0.8 mm for all scenarios. In conclusion, the current margin scheme with HDMM setting is adequate for a typical patient's intrafractional motion.
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Affiliation(s)
- Eun Young Han
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Parmeswaran Diagaradjane
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dershan Luo
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yao Ding
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Emmanouil Zoros
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Kyveli Zourari
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Evangelos Pappas
- Department of Biomedical Sciences, Radiology & Radiotherapy Sector, University of West Attica, Athens, Greece
| | - Zhifei Wen
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jihong Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tina Marie Briere
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Pappas E, Kalaitzakis G, Boursianis T, Zoros E, Zourari K, Pappas EP, Makris D, Seimenis I, Efstathopoulos E, Maris TG. Dosimetric performance of the Elekta Unity MR-linac system: 2D and 3D dosimetry in anthropomorphic inhomogeneous geometry. ACTA ACUST UNITED AC 2019; 64:225009. [DOI: 10.1088/1361-6560/ab52ce] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Makris DN, Pappas EP, Zoros E, Papanikolaou N, Saenz DL, Kalaitzakis G, Zourari K, Efstathopoulos E, Maris TG, Pappas E. Characterization of a novel 3D printed patient specific phantom for quality assurance in cranial stereotactic radiosurgery applications. Phys Med Biol 2019; 64:105009. [PMID: 30965289 DOI: 10.1088/1361-6560/ab1758] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In single-isocenter stereotactic radiosurgery/radiotherapy (SRS/SRT) intracranial applications, multiple targets are being treated concurrently, often involving non-coplanar arcs, small photon beams and steep dose gradients. In search for more rigorous quality assurance protocols, this work presents and evaluates a novel methodology for patient-specific pre-treatment plan verification, utilizing 3D printing technology. In a patient's planning CT scan, the external contour and bone structures were segmented and 3D-printed using high-density bone-mimicking material. The resulting head phantom was filled with water while a film dosimetry insert was incorporated. Patient and phantom CT image series were fused and inspected for anatomical coherence. HUs and corresponding densities were compared in several anatomical regions within the head. Furthermore, the level of patient-to-phantom dosimetric equivalence was evaluated both computationally and experimentally. A single-isocenter multi-focal SRS treatment plan was prepared, while dose distributions were calculated on both CT image series, using identical calculation parameters. Phantom- and patient-derived dose distributions were compared in terms of isolines, DVHs, dose-volume metrics and 3D gamma index (GI) analysis. The phantom was treated as if the real patient and film measurements were compared against the patient-derived calculated dose distribution. Visual inspection of the fused CT images suggests excellent geometric similarity between phantom and patient, also confirmed using similarity indices. HUs and densities agreed within one standard deviation except for the skin (modeled as 'bone') and sinuses (water-filled). GI comparison between the calculated distributions resulted in passing rates better than 97% (1%/1 mm). DVHs and dose-volume metrics were also in satisfying agreement. In addition to serving as a feasibility proof-of-concept, experimental absolute film dosimetry verified the computational study results. GI passing rates were above 90%. Results of this work suggest that employing the presented methodology, patient-equivalent phantoms (except for the skin and sinuses areas) can be produced, enabling literally patient-specific pre-treatment plan verification in intracranial applications.
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Affiliation(s)
- D N Makris
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens 115 27, Greece
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Hasani M, Farhood B, Ghorbani M, Naderi H, Saadatmand S, Karimkhani Zandi S, Knaup C. Effect of computed tomography number-relative electron density conversion curve on the calculation of radiotherapy dose and evaluation of Monaco radiotherapy treatment planning system. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:489-502. [PMID: 30848440 DOI: 10.1007/s13246-019-00745-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 02/27/2019] [Indexed: 11/24/2022]
Abstract
The accuracy of a computed tomography (CT)-relative electron density (RED) curve may have an indirect impact on the accuracy of dose calculation by a treatment planning system (TPS). This effect has not been previously quantified for input of different CT-RED curves from different CT-scan units in the Monaco TPS. This study aims to evaluate the effect of CT-RED curve on the dose calculation by the Monaco radiotherapy TPS. Four CT images of the CIRS phantom were obtained by different CT scanners. The accuracy of the dose calculation in the three algorithms of the Monaco TPS (Monte Carlo, collapse cone, and pencil beam) is also evaluated based on TECDOC 1583. The CT-RED curves from the CT scanners were transferred to the Monaco TPS to audit the different algorithms of the TPS. The dose values were measured with an ionization chamber in the CIRS phantom. Then, the dose values were calculated by the Monaco algorithms in the corresponding points. For the Monaco TPS and based on TECDOC 1583, the accuracy of the dose calculation in all the three algorithms is within the agreement criteria for most of the points evaluated. For low dose regions, the differences between the calculated and measured dose values are higher than the agreement criteria in a number of points. For the majority of the points, the algorithms underestimate the calculated dose values. It was also found that the use of different CT-RED curves can lead to minor discrepancies in the dose calculation by the Monaco TPS, especially in low dose regions. However, it appears that these differences are not clinically significant in most of the cases.
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Affiliation(s)
- Mohsen Hasani
- Department of Radiotherapy Physics, Cancer Research Centre, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Bagher Farhood
- Department of Medical Physics and Radiology, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran.
| | - Mahdi Ghorbani
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Hamideh Naderi
- Department of Radiotherapy Physics, Cancer Institute, Qom University of Medical Sciences, Qom, Iran
| | - Sepideh Saadatmand
- Department of Radiotherapy Physics, Cancer Institute, Qom University of Medical Sciences, Qom, Iran
| | - Saeed Karimkhani Zandi
- Department of Radiotherapy Physics, Cancer Institute, Qom University of Medical Sciences, Qom, Iran
| | - Courtney Knaup
- Comprehensive Cancer Centers of Nevada, Las Vegas, NV, USA
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