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Ohira S, Imae T, Minamitani M, Katano A, Aoki A, Ohta T, Umekawa M, Shinya Y, Hasegawa H, Nishio T, Koizumi M, Yamashita H, Saito N, Nakagawa K. Long-term geometric quality assurance of radiation focal point and cone-beam computed tomography for Gamma Knife radiosurgery system. Radiol Phys Technol 2024; 17:389-395. [PMID: 38466497 PMCID: PMC11128398 DOI: 10.1007/s12194-024-00788-9] [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: 10/16/2023] [Revised: 01/23/2024] [Accepted: 02/01/2024] [Indexed: 03/13/2024]
Abstract
To investigate the geometric accuracy of the radiation focal point (RFP) and cone-beam computed tomography (CBCT) over long-term periods for the ICON Leksell Gamma Knife radiosurgery system. This phantom study utilized the ICON quality assurance tool plus, and the phantom was manually set on the patient position system before the implementation of treatment for patients. The deviation of the RFP position from the unit center point (UCP) and the positions of the four ball bearings (BBs) in the CBCT from the reference position were automatically analyzed. During 544 days, a total of 269 analyses were performed on different days. The mean ± standard deviation (SD) of the deviation between measured RFP and UCP was 0.01 ± 0.03, 0.01 ± 0.03, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively. The deviations with offset values after the cobalt-60 source replacement (0.00 ± 0.03, -0.01 ± 0.01, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively) were significantly (p = 0.001) smaller than those before the replacement (0.02 ± 0.03, 0.02 ± 0.01, and -0.02 ± 0.01 mm in the X, Y, and Z directions, respectively). The overall mean ± SD of four BBs was -0.03 ± 0.03, -0.01 ± 0.05, and 0.01 ± 0.03 mm in the X, Y, and Z directions, respectively. Geometric positional accuracy was ensured to be within 0.1 mm on most days over a long-term period of more than 500 days.
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Affiliation(s)
- Shingo Ohira
- Department of Comprehensive Radiation Oncology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan.
| | - Toshikazu Imae
- Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan
| | - Masanari Minamitani
- Department of Comprehensive Radiation Oncology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Atsuto Katano
- Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan
| | - Atsushi Aoki
- Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan
| | - Takeshi Ohta
- Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan
| | - Motoyuki Umekawa
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Yuki Shinya
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan
- Department of Neurologic Surgery, Mayo Clinic, Rochester Minnesota, USA
| | - Hirotaka Hasegawa
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Teiji Nishio
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Hideomi Yamashita
- Department of Radiology, The University of Tokyo Hospital, Tokyo, Japan
| | - Nobuhito Saito
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Keiichi Nakagawa
- Department of Comprehensive Radiation Oncology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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Perrett B, Seshadri V, Huxley C, Kumar S, Wawrzak M, Ramachandran P. Evaluation of radiation detectors for the determination of field output factors in Leksell Gamma Knife dosimetry using 3D printed phantom inserts. Phys Med 2024; 121:103370. [PMID: 38677196 DOI: 10.1016/j.ejmp.2024.103370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 02/22/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024] Open
Abstract
The Leksell Gamma Knife® Perfexion™ and Icon™ have a unique geometry, containing 192 60Co sources with collimation for field sizes of 4 mm, 8 mm, and 16 mm. 4 mm and 8 mm collimated fields lack lateral charged particle equilibrium, so accurate field output factors are essential. This study performs field output factor measurements for the microDiamond, microSilicon, and RAZOR™ Nano detectors. 3D printed inserts for the spherical Solid Water® Phantom were fabricated for microDiamond detector, the microSilicon unshielded diode and the RAZOR™ Nano micro-ionisation chamber. Detectors were moved iteratively to identify the peak detector signal for each collimator, representing the effective point of measurement of the chamber. In addition, field output correction factors were calculated for each detector relative to vendor supplied Monte Carlo simulated field output factors and field output factors measured with a W2 scintillator. All field output factors where within 1.1 % for the 4 mm collimator and within 2.3 % for the 8 mm collimator. The 3D printed phantom inserts were suitable for routine measurements if the user identifies the effective point of measurement, and ensures a reproducible setup by marking the rotational alignment of the cylindrical print. Measurements with the microDiamond and microSilicon can be performed faster compared to the RAZOR™ Nano due to differences in the signal to noise ratio. All detectors are suitable for field output factor measurements for the Leksell Gamma Knife® Perfexion™ and Icon™.
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Affiliation(s)
- Ben Perrett
- Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Queensland 4102, Australia.
| | - Venkatakrishnan Seshadri
- Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Queensland 4102, Australia
| | - Cosmo Huxley
- 3DOne Australia Pty Ltd, 30 Nashos Place, Wacol, Queensland 4102, Australia
| | - Sanjay Kumar
- Elekta Australia and New Zealand Pty Ltd, Suite 10.02, 146 Arthur Street, North Sydney, New South Wales 2060, Australia
| | - Michal Wawrzak
- Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Queensland 4102, Australia
| | - Prabhakar Ramachandran
- Radiation Oncology, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Queensland 4102, Australia
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Samanci Y, Askeroglu MO, Düzkalir AH, Peker S. Assessing the impact of distortion correction on Gamma Knife radiosurgery for multiple metastasis: Volumetric and dosimetric analysis. BRAIN & SPINE 2024; 4:102791. [PMID: 38584868 PMCID: PMC10995810 DOI: 10.1016/j.bas.2024.102791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/09/2024]
Abstract
Introduction Magnetic resonance imaging (MRI) is a robust neuroimaging technique and is the preferred method for stereotactic radiosurgery (SRS) planning. However, MRI data always contain distortions caused by hardware and patient factors. Research question Can these distortions potentially compromise the effectiveness and safety of SRS treatments? Material and methods Twenty-six MR datasets with multiple metastatic brain tumors (METs) used for Gamma Knife radiosurgery (GKRS) were retrospectively evaluated. A commercially available software was used for distortion correction. Geometrical agreement between corrected and uncorrected tumor volumes was evaluated using MacDonald criteria, Euclidian distance, and Dice similarity coefficient (DSC). SRS plans were generated using uncorrected tumor volumes, which were assessed to determine their coverage of the corrected tumor volumes. Results The median target volume was 0.38 cm3 (range,0.01-12.38 cm3). A maximum displacement of METs of up to 2.87 mm and a median displacement of 0.55 mm (range,0.1-2.87 mm) were noted. The median DSC between uncorrected and corrected MRI was 0.92, and the most concerning case had a DSC of 0.46. Although all plans met the optimization criterion of at least 98% of the uncorrected tumor volume (median 99.55%, range 98.1-100%) receiving at least 100% of the prescription dose, the percent of the corrected tumor volume receiving the total prescription dose was a median of 95.45% (range,23.1-99.5%). Discussion and conclusion MRI distortion, though visually subtle, has significant implications for SRS planning. Regular utilization of corrected MRI is recommended for SRS planning as distortion is sometimes enough to cause a volumetric miss of SRS targets.
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Affiliation(s)
- Yavuz Samanci
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - M. Orbay Askeroglu
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - Ali Haluk Düzkalir
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
- Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - Selcuk Peker
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
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Semeniuk O, Yu E, Rivard MJ. Current and Emerging Radiotherapy Options for Uveal Melanoma. Cancers (Basel) 2024; 16:1074. [PMID: 38473430 DOI: 10.3390/cancers16051074] [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: 01/21/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
What treatment options are there for patients having uveal melanoma? A randomized, prospective, multi-institutional clinical trial (COMS) showed no difference in survival between brachytherapy and enucleation for medium-sized lesions. With the obvious benefit of retaining the eye, brachytherapy has flourished and many different approaches have been developed such as low-dose-rate sources using alternate low-energy photon-emitting radionuclides, different plaque designs and seed-loading techniques, high-dose-rate brachytherapy sources and applicators, and low- and high-dose-rate beta-emitting sources and applicators. There also have been developments of other radiation modalities like external-beam radiotherapy using linear accelerators with high-energy photons, particle accelerators for protons, and gamma stereotactic radiosurgery. This article examines the dosimetric properties, targeting capabilities, and outcomes of these approaches. The several modalities examined herein have differing attributes and it may be that no single approach would be considered optimal for all patients and all lesion characteristics.
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Affiliation(s)
- Oleksii Semeniuk
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
| | - Esther Yu
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
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Hanvey S, Hackett P, Winch L, Lim E, Laney R, Welsh L. A multi-centre stereotactic radiosurgery planning study of multiple brain metastases using isocentric linear accelerators with 5 and 2.5 mm width multi-leaf collimators, CyberKnife and Gamma Knife. BJR Open 2024; 6:tzae003. [PMID: 38371494 PMCID: PMC10873585 DOI: 10.1093/bjro/tzae003] [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: 02/15/2024] [Revised: 02/15/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024] Open
Abstract
Objectives This study compared plans of high definition (HD), 2.5 mm width multi-leaf collimator (MLC), to standard, 5 mm width, isocentric linear accelerator (linacs), CyberKnife (CK), and Gamma Knife (GK) for stereotactic radiosurgery (SRS) techniques on multiple brain metastases. Methods Eleven patients undergoing SRS for multiple brain metastases were chosen. Targets and organs at risk (OARs) were delineated and optimized SRS plans were generated and compared. Results The linacs delivered similar conformity index (CI) values, but the gradient index (GI) for HD MLCs was significantly lower (P-value <.001). Half the OARs received significantly lower dose using HD MLCs. CK delivered a significantly lower CI than HD MLC linac (P-value <.001), but a significantly higher GI (P-value <.001). CI was significantly improved with the HD MLC linac compared to GK (P-value = 4.591 × 10-3), however, GK delivered a significantly lower GI (P-value <.001). OAR dose sparing was similar for the HD MLC TL, CK, and GK. Conclusions Comparing linacs for SRS, the preferred choice is HD MLCs. Similar results were achieved with the HD MLC linac, CK, or GK, with each delivering significant improvements in different aspects of plan quality. Advances in knowledge This article is the first to compare HD and standard width MLC linac plans using a combination of single isocentre volumetric modulated arc therapy and multi-isocentric dynamic conformal arc plans as required, which is a more clinically relevant assessment. Furthermore, it compares these plans with CK and GK, assessing the relative merits of each technique.
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Affiliation(s)
- Scott Hanvey
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
| | | | - Lucy Winch
- University Hospitals Bristol NHS Foundation Trust, Bristol, BS2 8ED, United Kingdom
| | - Elizabeth Lim
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
- University of Plymouth, Plymouth, PL4 8AA, United Kingdom
| | - Robin Laney
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
| | - Liam Welsh
- The Royal Marsden, London, SW3 6JJ, United Kingdom
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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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Safari M, Fatemi A, Afkham Y, Archambault L. Patient-specific geometrical distortion corrections of MRI images improve dosimetric planning accuracy of vestibular schwannoma treated with gamma knife stereotactic radiosurgery. J Appl Clin Med Phys 2023; 24:e14072. [PMID: 37345614 PMCID: PMC10562030 DOI: 10.1002/acm2.14072] [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: 02/07/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/23/2023] Open
Abstract
PURPOSE To investigate the impact of MRI patient-specific geometrical distortion (PSD) on the quality of Gamma Knife stereotactic radiosurgery (GK-SRS) plans of the vestibular schwannoma (VS) tumors. METHODS AND MATERIALS Three open access datasets including the MPI-Leipzig Mind-Brain-Body (318 patients), the slow event-related fMRI designs dataset (62 patients), and the VS dataset (242 patients) were used. We used first two datasets to train a 3D convolution network to predict the distortion map of third dataset that were then used to calculate and correct the PSD. GK-SRS plans of VS dataset were used to evaluate dose distribution of PSD-corrected MRI images. GK-SRS prescription dose of VS cases was 12 Gy. Geometric and dosimetric discrepancies were assessed between the dose distributions and contours before and after the PSD corrections. Geometry indices were center of the contours, Dice coefficient (DC), Hausdorff distance (HD), and dosimetric indices wereD μ ${D_\mu }$ ,D m a x ${D_{max}}$ ,D m i n ${D_{min}}$ , andD 95 % ${D_{95{\mathrm{\% }}}}$ doses, target coverage (TC), Paddick's conformity index (PCI), Paddick's gradient index (GI), and homogeneity index (HI). RESULTS Geometric distortions of about 1.2 mm were observed at the air-tissue interfaces at the air canal and nasal cavity borders. Average center of the targets was significantly distorted along the frequency encoding direction after the PSD-correction. Average DC and HD metrics were 0.90 and 2.13 mm. AverageD μ ${D_\mu }$ ,D 95 % , ${D_{95{\mathrm{\% ,}}}}$ andD m i n ${D_{min}}$ in Gy significantly increased after PSD correction from 16.85 to 17.25, 12.30 to 12.77, and from 8.98 to 9.92.D m a x ${D_{max}}$ did not significantly change after the correction. Average TC and PCI significantly increased from 0.97 to 0.98, and 0.94 to 0.96. Average GI decreased significantly from 2.24 to 2.15 after PSD correction. However, HI did not significantly change after the correction. CONCLUSION The proposed method could predict and correct the PSD that indicates the importance of PSD correction before GK-SRS plans of the VS patients.
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Affiliation(s)
- Mojtaba Safari
- Département de physiquede génie physique et d'optiqueet Centre de recherche sur le cancerUniversité LavalQuébecQuébecCanada
- Service de physique médicale et de radioprotectionCentre Intégré de CancérologieCHU de Québec‐Université Laval et Centre de recherche du CHU de QuébecQuébecQuébecCanada
| | - Ali Fatemi
- Department of PhysicsJackson State UniversityMississippiUSA
- Merit Health CentralDepartment of Radiation OncologyGamma Knife CenterMississippiUSA
| | - Younes Afkham
- Clinical Research Development Unit of Tabriz Valiasr HospitalTabriz University of Medical ScienceTabrizIran
| | - Louis Archambault
- Département de physiquede génie physique et d'optiqueet Centre de recherche sur le cancerUniversité LavalQuébecQuébecCanada
- Service de physique médicale et de radioprotectionCentre Intégré de CancérologieCHU de Québec‐Université Laval et Centre de recherche du CHU de QuébecQuébecQuébecCanada
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Wang Z, Sun X, Wang W, Zhang T, Chen L, Duan J, Feng S, Chen Y, Wei Z, Zang J, Xiao F, Zhao L. Characterization and commissioning of a new collaborative multi-modality radiotherapy platform. Phys Eng Sci Med 2023; 46:981-994. [PMID: 37378823 PMCID: PMC10480288 DOI: 10.1007/s13246-023-01255-2] [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: 12/12/2022] [Accepted: 03/31/2023] [Indexed: 06/29/2023]
Abstract
TaiChi, a new multi-modality radiotherapy platform that integrates a linear accelerator, a focusing gamma system, and a kV imaging system within an enclosed O-ring gantry, was introduced into clinical application. This work aims to assess the technological characteristics and commissioning results of the TaiChi platform. The acceptance testing and commissioning were performed following the manufacturer's customer acceptance tests (CAT) and several AAPM Task Group (TG) reports/guidelines. Regarding the linear accelerator (linac), all applicable validation measurements recommended by the MPPG 5.a (basic photon beam model validation, intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) validation, end-to-end(E2E) tests, and patient-specific quality assurance (QA)) were performed. For the focusing gamma system, the absorbed doses were measured using a PTW31014 ion chamber (IC) and PTW60016 diode detector. EBT3 films and a PTW60016 diode detector were employed to measure the relative output factors (ROFs). The E2E tests were performed using PTW31014 IC and EBT3 films. The coincidences between the imaging isocenter and the linac/gamma mechanical isocenter were investigated using EBT3 films. The image quality was evaluated regarding the contrast-to-noise ratio (CNR), spatial resolution, and uniformity. All tests included in the CAT met the manufacturer's specifications. All MPPG 5.a measurements complied with the tolerances. The confidence limits for IMRT/VMAT point dose and dose distribution measurements were achieved according to TG-119. The point dose differences were below 1.68% and gamma passing rates (3%/2 mm) were above 95.1% for the linac E2E tests. All plans of patient-specific QA had point dose differences below 1.79% and gamma passing rates above 96.1% using the 3%/2 mm criterion suggested by TG-218. For the focusing gamma system, the differences between the calculated and measured absorbed doses were below 1.86%. The ROFs calculated by the TPS were independently confirmed within 2% using EBT3 films and a PTW60016 detector. The point dose differences were below 2.57% and gamma passing rates were above 95.3% using the 2%/1 mm criterion for the E2E tests. The coincidences between the imaging isocenter and the linac/gamma mechanical isocenter were within 0.5 mm. The image quality parameters fully complied with the manufacturer's specifications regarding the CNR, spatial resolution, and uniformity. The multi-modality radiotherapy platform complies with the CAT and AAPM commissioning criteria. The commissioning results demonstrate that this platform performs well in mechanical and dosimetry accuracy.
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Affiliation(s)
- Zhongfei Wang
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Xiaohuan Sun
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Wei Wang
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Te Zhang
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Liting Chen
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Jie Duan
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Siqi Feng
- Our United Corporation, 710018, Xi'an, Shaanxi Province, P.R. China
| | - Yinzhu Chen
- Our United Corporation, 710018, Xi'an, Shaanxi Province, P.R. China
| | - Zhiwei Wei
- Our United Corporation, 710018, Xi'an, Shaanxi Province, P.R. China
| | - Jian Zang
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China
| | - Feng Xiao
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China.
| | - Lina Zhao
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, 710032, Xi'an, Shaanxi Province, P.R. China.
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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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Damyanovich AZ, Tadic T, Foltz WD, Jelveh S, Bissonnette JP. Time-course assessment of 3D-image distortion on the 1.5 T Marlin/Elekta Unity MR-LINAC. Phys Med 2022; 100:90-98. [PMID: 35777256 DOI: 10.1016/j.ejmp.2022.05.009] [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: 01/05/2022] [Revised: 04/04/2022] [Accepted: 05/25/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The efficacy of MR-guided radiotherapy on a MR-LINAC (MR-L) is dependent on the geometric accuracy of its MR images over clinically relevant Fields-of-View (FOVs). Our objectives were to: evaluate gradient non-linearity (GNL) on the Elekta Unity MR-L across time via 76 weekly measurements of 3D-distortion over concentrically larger diameter spherical volumes (DSVs); quantify distortion measurement error; and assess the temporal stability of spatial distortion using statistical process control (SPC). METHODS MR-image distortion was assessed using a large-FOV 3D-phantom containing 1932 markers embedded in seven parallel plates, spaced 25 mm × 25 mm in- and 55 mm through-plane. Automatically analyzed T1 images yielded distortions in 200, 300, 400 and 500 mm concentric DSVs. Distortion measurement error was evaluated using median absolute difference analysis of imaging repeatability tests. RESULTS Over the measurement period absolute time-averaged distortion varied between: dr = 0.30 - 0.49 mm, 0.53 - 0.80 mm, 1.0 - 1.4 mm and 2.28 - 2.37 mm, for DSVs 200, 300, 400 and 500 mm at the 98th percentile level. Repeatability tests showed that imaging/repositioning introduces negligible error: mean ≤ 0.02 mm (max ≤ 0.3 mm). SPC analysis showed image distortion was stable across all DSVs; however, noticeable changes in GNL were observed following servicing at the one-year mark. CONCLUSIONS Image distortion on the MR-L is in the sub-millimeter range for DSVs ≤ 300 mm and stable across time, with SPC analysis indicating all measurements remain within control for each DSV.
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Affiliation(s)
- Andrei Z Damyanovich
- Department of Medical Physics, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Techna Institute, Toronto, Ontario, Canada.
| | - Tony Tadic
- Department of Medical Physics, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Techna Institute, Toronto, Ontario, Canada
| | - Warren D Foltz
- Department of Medical Physics, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Techna Institute, Toronto, Ontario, Canada
| | - Salomeh Jelveh
- Department of Medical Physics, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada
| | - Jean-Pierre Bissonnette
- Department of Medical Physics, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Techna Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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11
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Taylor PA, Moran JM, Jaffray DA, Buchsbaum JC. A roadmap to clinical trials for FLASH. Med Phys 2022; 49:4099-4108. [PMID: 35366339 PMCID: PMC9321729 DOI: 10.1002/mp.15623] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 02/17/2022] [Accepted: 03/17/2022] [Indexed: 11/29/2022] Open
Abstract
While FLASH radiation therapy is inspiring enthusiasm to transform the field, it is neither new nor well understood with respect to the radiobiological mechanisms. As FLASH clinical trials are designed, it will be important to ensure we can deliver dose consistently and safely to every patient. Much like hyperthermia and proton therapy, FLASH is a promising new technology that will be complex to implement in the clinic and similarly will require customized credentialing for multi‐institutional clinical trials. There is no doubt that FLASH seems promising, but many technologies that we take for granted in conventional radiation oncology, such as rigorous dosimetry, 3D treatment planning, volumetric image guidance, or motion management, may play a major role in defining how to use, or whether to use, FLASH radiotherapy. Given the extended time frame for patients to experience late effects, we recommend moving deliberately but cautiously forward toward clinical trials. In this paper, we review the state of quality assurance and safety systems in FLASH, identify critical pre‐clinical data points that need to be defined, and suggest how lessons learned from previous technological advancements will help us close the gaps and build a successful path to evidence‐driven FLASH implementation.
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Affiliation(s)
- Paige A Taylor
- The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jean M Moran
- Memorial Sloan Kettering Cancer, New York, New York
| | - David A Jaffray
- The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jeffrey C Buchsbaum
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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12
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Pappas EP, Seimenis I, Kouris P, Theocharis S, Lampropoulos KI, Kollias G, Karaiskos P. Target localization accuracy in frame‐based stereotactic radiosurgery: Comparison between MR‐only and MR/CT co‐registration approaches. J Appl Clin Med Phys 2022; 23:e13580. [PMID: 35285583 PMCID: PMC9121047 DOI: 10.1002/acm2.13580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 11/28/2022] Open
Abstract
Purpose In frame‐based Gamma Knife (GK) stereotactic radiosurgery two treatment planning workflows are commonly employed; one based solely on magnetic resonance (MR) images and the other based on magnetic resonance/computed tomography (MR/CT) co‐registered images. In both workflows, target localization accuracy (TLA) can be deteriorated due to MR‐related geometric distortions and/or MR/CT co‐registration uncertainties. In this study, the overall TLA following both clinical workflows is evaluated for cases of multiple brain metastases. Methods A polymer gel‐filled head phantom, having the Leksell stereotactic headframe attached, was CT‐imaged and irradiated by a GK Perfexion unit. A total of 26 4‐mm shots were delivered at 26 locations directly defined in the Leksell stereotactic space (LSS), inducing adequate contrast in corresponding T2‐weighted (T2w) MR images. Prescribed shot coordinates served as reference locations. An additional MR scan was acquired to implement the “mean image” distortion correction technique. The TLA for each workflow was assessed by comparing the radiation‐induced target locations, identified in MR images, with corresponding reference locations. Using T1w MR and CT images of 15 patients (totaling 81 lesions), TLA in clinical cases was similarly assessed, considering MR‐corrected data as reference. For the MR/CT workflow, both global and region of interest (ROI)‐based MR/CT registration approaches were studied. Results In phantom measurements, the MR‐corrected workflow demonstrated unsurpassed TLA (median offset of 0.2 mm) which deteriorated for MR‐only and MR/CT workflows (median offsets of 0.8 and 0.6 mm, respectively). In real‐patient cases, the MR‐only workflow resulted in offsets that exhibit a significant positive correlation with the distance from the MR isocenter, reaching 1.1 mm (median 0.6 mm). Comparable results were obtained for the MR/CT‐global workflow, although a maximum offset of 1.4 mm was detected. TLA was improved with the MR/CT‐ROI workflow resulting in median/maximum offsets of 0.4 mm/1.1 mm. Conclusions Subpixel TLA is achievable in all workflows. For the MR/CT workflow, a ROI‐based MR/CT co‐registration approach could considerably increase TLA and should be preferred instead of a global registration.
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Affiliation(s)
- Eleftherios P. Pappas
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Ioannis Seimenis
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Panagiotis Kouris
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Stefanos Theocharis
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | | | - Georgios Kollias
- Medical Physics and Gamma Knife Department Hygeia Hospital Marousi Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
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13
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Kron T, Fox C, Ebert MA, Thwaites D. Quality management in radiotherapy treatment delivery. J Med Imaging Radiat Oncol 2022; 66:279-290. [PMID: 35243785 DOI: 10.1111/1754-9485.13348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022]
Abstract
Radiation Oncology continues to rely on accurate delivery of radiation, in particular where patients can benefit from more modulated and hypofractioned treatments that can deliver higher dose to the target while optimising dose to normal structures. These deliveries are more complex, and the treatment units are more computerised, leading to a re-evaluation of quality assurance (QA) to test a larger range of options with more stringent criteria without becoming too time and resource consuming. This review explores how modern approaches of risk management and automation can be used to develop and maintain an effective and efficient QA programme. It considers various tools to control and guide radiation delivery including image guidance and motion management. Links with typical maintenance and repair activities are discussed, as well as patient-specific quality control activities. It is demonstrated that a quality management programme applied to treatment delivery can have an impact on individual patients but also on the quality of treatment techniques and future planning. Developing and customising a QA programme for treatment delivery is an important part of radiotherapy. Using modern multidisciplinary approaches can make this also a useful tool for department management.
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Affiliation(s)
- Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Sir Peter MacCallum Institute of Oncology, Melbourne University, Melbourne, Victoria, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
| | - Chris Fox
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Martin A Ebert
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia.,Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,School of Physics, Mathematics and Computing, University of Western Australia, Perth, Western Australia, Australia.,5D Clinics, Perth, Western Australia, Australia
| | - David Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales, Australia.,Medical Physics Group, Leeds Institute of Cardiovascular and Metabolic Medicine and Leeds Institute of Medical Research, University of Leeds, Leeds, UK
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14
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Das IJ, Dawes SL, Dominello MM, Kavanagh B, Miyamoto CT, Pawlicki T, Santanam L, Vinogradskiy Y, Yeung AR. Quality and Safety Considerations in Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy: An ASTRO Safety White Paper Update. Pract Radiat Oncol 2022; 12:e253-e268. [DOI: 10.1016/j.prro.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/01/2022] [Indexed: 11/17/2022]
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15
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Duggar WN, Morris B, He R, Yang C. Total workflow uncertainty of frameless radiosurgery with the Gamma Knife Icon cone-beam computed tomography. J Appl Clin Med Phys 2022; 23:e13564. [PMID: 35157361 PMCID: PMC9121051 DOI: 10.1002/acm2.13564] [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: 10/29/2021] [Revised: 12/29/2021] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Objective Frameless treatment with the Gamma Knife Icon is still relatively new as a treatment option. As a result, additional confidence/knowledge about the uncertainty that exists within each portion of the treatment workflow could be gained especially regarding steps that have not been previously studied in the literature. Methods The Icon base delivery device (Perfexion) uncertainty is quantified and validated. The novel portions of the Icon such as mask immobilization, cone‐beam computed tomography image guidance, and the intrafraction motion management methods are studied specifically and to a greater extent to determine a total workflow uncertainty of frameless treatment with the Icon. Results The uncertainty of each treatment workflow step has been identified with the total workflow uncertainty being identified in this work as 1.3 mm with a standard deviation of 0.51 mm. Conclusion The total uncertainty of frameless treatment with the Icon has been evaluated and this data may indicate the need for setup margin in this setting with data that could be used by other institutions to calculate needed setup margin per their preferred recipe after validation of this data in their context.
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Affiliation(s)
- William N Duggar
- Department of Radiation Oncology, University of MS Medical Center, Jackson, Mississippi, USA
| | - Bart Morris
- Department of Radiation Oncology, University of MS Medical Center, Jackson, Mississippi, USA
| | - Rui He
- Department of Radiation Oncology, University of MS Medical Center, Jackson, Mississippi, USA
| | - Claus Yang
- Department of Radiation Oncology, University of MS Medical Center, Jackson, Mississippi, USA
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16
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Rudek B, Bernstein K, Osterman S, Qu T. Replacing gamma knife beam-profiles on film with point-detector scans. J Appl Clin Med Phys 2022; 23:e13522. [PMID: 35001499 DOI: 10.1002/acm2.13522] [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: 08/20/2021] [Revised: 12/02/2021] [Accepted: 12/15/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Detector arrays and profile-scans have widely replaced film-measurements for quality assurance (QA) on linear accelerators. Film is still used for relative output factor (ROF) measurements, positioning, and dose-profile verification for annual Leksell Gamma Knife (LGK) QA. This study shows that small-field active detector measurements can be performed in the easily accessed clinical mode and that they are an effective replacement to time-consuming and exacting film measurements. METHODS Beam profiles and positioning scans for 4-mm, 8-mm, and 16-mm-collimated fields were collected along the x-, y-, and z-axes. The Exradin W2-scintillator and the PTW microdiamond-detector were placed in custom inserts centered in the Elekta solid-water phantom for these scans. GafChromic EBT3-film was irradiated with single uniformly collimated exposures as the clinical-standard reference, using the same solid-water phantom for profile tests and the Elekta film holder for radiation focal point (RFP)/patient-positioning system (PPS) coincidence. All experimental data were compared to the tissue-maximum-ratio-based (TMR10) dose calculation. RESULTS The detector-measured beam profiles and film-based profiles showed excellent agreement with TMR10-predicted full-width, half-maximum (FWHM) values. Absolute differences between the measured FWHM and FWHM from the treatment-planning system were on average 0.13 mm, 0.08 mm, and 0.04 mm for film, microdiamond, and scintillator, respectively. The coincidence between the RFP and the PPS was measured to be ≤0.5 mm with microdiamond, ≤0.41 mm with the W2-1 × 1 scintillator, and ≤0.22 mm using the film-technique. CONCLUSIONS Small-volume field detectors, used in conjunction with a clinically available phantom, an electrometer with data-logging, and treatment plans created in clinical mode offer an efficient and viable alternative for film-based profile tests. Position verification can be accurately performed when CBCT-imaging is available to correct for residual detector-position uncertainty. Scans are easily set up within the treatment-planning-system and, when coupled with an automated analysis, can provide accurate measurements within minutes.
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Affiliation(s)
- Benedikt Rudek
- Department of Radiation Oncology, Laura and Isaac Perlmutter Cancer Center, NYU Langone Health, New York, New York, USA
| | - Kenneth Bernstein
- Department of Radiation Oncology, Laura and Isaac Perlmutter Cancer Center, NYU Langone Health, New York, New York, USA
| | - Sunshine Osterman
- Department of Radiation Oncology, NYU Grossman School of Medicine, New York University, New York, New York, USA
| | - Tanxia Qu
- Department of Radiation Oncology, NYU Grossman School of Medicine, New York University, New York, New York, USA
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17
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Schlesinger DJ, Sanders JC, Muller DA, Nordström H, Sheehan JP. 8+ Year Performance of the Gamma Knife Perfexion/Icon Patient Positioning System and Possibilities for Preemptive Fault Detection Using Statistical Process Control. Med Phys 2021; 48:3425-3437. [PMID: 33959977 DOI: 10.1002/mp.14924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/23/2021] [Accepted: 04/24/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The large fractional doses, steep dose gradients, and small targets found in intracranial radiosurgery require extremely low beam delivery uncertainty. In the case of Gamma Knife radiosurgery (GKRS), this includes minimizing patient positioning system (PPS) positioning uncertainty. Existing QA techniques are recipe based, and feature point in time pass/fail tolerances. However, modern treatment machines, including the Gamma Knife Perfexion/Icon systems, record extensive internal data in treatment logs. These data can be analyzed through statistical process control (SPC) methods which are designed to detect changes in process behavior. The purpose of this study was to characterize the long-term (8+ year) performance of a Perfexion/Icon unit and use SPC methods to determine if performance changes could be detected at levels lower than existing QA and internal manufacturer performance tolerances. METHODS In-house software was developed to parse Perfexion/Icon log-files and store relevant information on shot delivery in a relational database. A last-in, first-out (LIFO) queuing algorithm was created to heuristically match messages associated with a given delivered shot. Filtering criteria were developed to filter QA and uncompleted shots. The resulting matched shots were extracted. Achieved versus planned PPS position was determined for each PPS motor as well as for the vector magnitude difference in PPS position. Exponentially weighted moving average (EWMA) control charts were plotted to determine when process behavior changed over time. RESULTS 53833 shots were delivered over an 8+ year span in the study. The mean vector magnitude PPS difference was 32.7 µm, with 97.5% of all shots within 70.1 µm. Several changes in PPS positioning behavior were observed over time, corresponding with control system faults on several occasions requiring PPS recalibration. EWMA control charts clearly demonstrate that these faults could be identified and possibly predicted as many as 3 years before there were faults beyond control system tolerance. CONCLUSION The PPS of Gamma Knife Perfexion/Icon systems has extremely low positioning uncertainties. EWMA control chart method can be utilized to track PPS performance over time and can potentially detect changes in performance that may indicate a component requiring maintenance. This would allow planned service visits to mitigate problems and prevent unplanned downtime.
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Affiliation(s)
- David J Schlesinger
- Departments of Radiation Oncology, University of Virginia, Charlottesville, VA, USA.,Department of Neurological Surgery, University of Virginia, Charlottesville, VA, USA
| | - Jason C Sanders
- Departments of Radiation Oncology, University of Virginia, Charlottesville, VA, USA
| | - Donald A Muller
- Departments of Radiation Oncology, University of Virginia, Charlottesville, VA, USA
| | | | - Jason P Sheehan
- Departments of Radiation Oncology, University of Virginia, Charlottesville, VA, USA.,Department of Neurological Surgery, University of Virginia, Charlottesville, VA, USA.,Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
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18
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Das IJ, Francescon P, Moran JM, Ahnesjö A, Aspradakis MM, Cheng CW, Ding GX, Fenwick JD, Saiful Huq M, Oldham M, Reft CS, Sauer OA. Report of AAPM Task Group 155: Megavoltage photon beam dosimetry in small fields and non-equilibrium conditions. Med Phys 2021; 48:e886-e921. [PMID: 34101836 DOI: 10.1002/mp.15030] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/06/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022] Open
Abstract
Small-field dosimetry used in advance treatment technologies poses challenges due to loss of lateral charged particle equilibrium (LCPE), occlusion of the primary photon source, and the limited choice of suitable radiation detectors. These challenges greatly influence dosimetric accuracy. Many high-profile radiation incidents have demonstrated a poor understanding of appropriate methodology for small-field dosimetry. These incidents are a cause for concern because the use of small fields in various specialized radiation treatment techniques continues to grow rapidly. Reference and relative dosimetry in small and composite fields are the subject of the International Atomic Energy Agency (IAEA) dosimetry code of practice that has been published as TRS-483 and an AAPM summary publication (IAEA TRS 483; Dosimetry of small static fields used in external beam radiotherapy: An IAEA/AAPM International Code of Practice for reference and relative dose determination, Technical Report Series No. 483; Palmans et al., Med Phys 45(11):e1123, 2018). The charge of AAPM task group 155 (TG-155) is to summarize current knowledge on small-field dosimetry and to provide recommendations of best practices for relative dose determination in small megavoltage photon beams. An overview of the issue of LCPE and the changes in photon beam perturbations with decreasing field size is provided. Recommendations are included on appropriate detector systems and measurement methodologies. Existing published data on dosimetric parameters in small photon fields (e.g., percentage depth dose, tissue phantom ratio/tissue maximum ratio, off-axis ratios, and field output factors) together with the necessary perturbation corrections for various detectors are reviewed. A discussion on errors and an uncertainty analysis in measurements is provided. The design of beam models in treatment planning systems to simulate small fields necessitates special attention on the influence of the primary beam source and collimating devices in the computation of energy fluence and dose. The general requirements for fluence and dose calculation engines suitable for modeling dose in small fields are reviewed. Implementations in commercial treatment planning systems vary widely, and the aims of this report are to provide insight for the medical physicist and guidance to developers of beams models for radiotherapy treatment planning systems.
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Affiliation(s)
- Indra J Das
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Paolo Francescon
- Department of Radiation Oncology, Ospedale Di Vicenza, Vicenza, Italy
| | - Jean M Moran
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Anders Ahnesjö
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Maria M Aspradakis
- Institute of Radiation Oncology, Cantonal Hospital of Graubünden, Chur, Switzerland
| | - Chee-Wai Cheng
- Department of Radiation Oncology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - George X Ding
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - John D Fenwick
- Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - M Saiful Huq
- Department of Radiation Oncology, University of Pittsburgh, School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Mark Oldham
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - Chester S Reft
- Department of Radiation Oncology, University of Chicago, Chicago, IL, USA
| | - Otto A Sauer
- Department of Radiation Oncology, Klinik fur Strahlentherapie, University of Würzburg, Würzburg, Germany
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