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Fogliata A, Burger H, Groenewald A, Punt L, Parkes J, Cozzi L. Intensity Modulated Therapy for Patients With Breast Cancer. Practical Guidelines and Tips for an Effective Treatment Planning Strategy. Adv Radiat Oncol 2024; 9:101535. [PMID: 38993192 PMCID: PMC11233865 DOI: 10.1016/j.adro.2024.101535] [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: 04/14/2023] [Accepted: 03/16/2024] [Indexed: 07/13/2024] Open
Abstract
Purpose Practical guidelines and tips for effective and robust radiation therapy treatment planning for patients with breast cancer are addressed for fixed-field intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) techniques. The concepts described here are general and valid on all treatment planning systems. However, some details shown here have been applied to the Varian platforms used at the authors' institutions. Methods and Materials The specific aspects of using C-arm- or O-ring-mounted linear accelerators are covered in the document, as well as tips for dealing with certain resource constraints, target cropping, and skin flash aiming to reduce risks of skin toxicity and to manage (residual after breath control) respiration motion or edema. Results A decision tree is presented, and practical solutions for cases where a target volume is contoured or not and where volumetric modulated arc therapy or fixed-beam intensity modulation should be applied and details about the technical implementation (tangential IMRT, butterfly IMRT or VMAT, and large partial VMAT arcs) are discussed. Target cropping and skin flash implications are discussed in detail, and links to plan robustness are outlined. Conclusions Practical guidelines for breast planning are presented and summarized with a decision tree and technical summaries.
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Affiliation(s)
- Antonella Fogliata
- Department of Radiotherapy and Radiosurgery, Istituto di Ricovero e Cura a Carattere Scientifico Humanitas Research Hospital, Rozzano, Italy
| | - Hester Burger
- Department of Radiation Medicine, Groote Schuur Hospital and the University of Cape Town, Cape Town, South Africa
- Medical Affairs, Varian Medical Systems, a Siemens Healthineers Company, Palo Alto, California
| | - Annemari Groenewald
- Department of Radiation Medicine, Groote Schuur Hospital and the University of Cape Town, Cape Town, South Africa
| | - Lydia Punt
- Department of Radiation Medicine, Groote Schuur Hospital and the University of Cape Town, Cape Town, South Africa
| | - Jeannette Parkes
- Department of Radiation Medicine, Groote Schuur Hospital and the University of Cape Town, Cape Town, South Africa
| | - Luca Cozzi
- Department of Radiotherapy and Radiosurgery, Istituto di Ricovero e Cura a Carattere Scientifico Humanitas Research Hospital, Rozzano, Italy
- Medical Affairs, Varian Medical Systems, a Siemens Healthineers Company, Palo Alto, California
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Hayes C, King RB, Hounsell AR, Agnew CE. Impact of target degradation on the 6FFF output of a Varian TrueBeam Linac. Phys Med 2024; 124:103424. [PMID: 39002424 DOI: 10.1016/j.ejmp.2024.103424] [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: 03/04/2024] [Revised: 06/07/2024] [Accepted: 06/29/2024] [Indexed: 07/15/2024] Open
Abstract
The dosimetric output of a 6FFF beam, produced from a Varian TrueBeam linac exhibited an unexpected downward trend over time that was contrary to well-established expectations. To elucidate the cause of this uncharacteristic trend, a review of the linac's quality control results over its lifetime was performed, including, constancy checks of the dosimetric output, beam energy, flatness and symmetry, and percentage depth dose characteristics. These results were supplemented with a comprehensive series of measurements including flatness and symmetry measurements with a 1D-diode array, high-resolution measurements of the photon beam's build-up region with a parallel-plate chamber and measurement of the beam's output as a function of the x-ray target position. The review of the linac's QC results and supplemental tests identified no deviations in the linac's performance from its commissioning and baseline measurements. However, the 6FFF beam output exhibited a significant dependence on the target location relative to its default position, increasing by 5.43 % with a 0.5 mm target translation, indicating that target degradation was the cause of the atypical output trend. The change in output behaviour was believed to be the result of primary electrons escaping the degraded target and interacting with the linac's monitor chamber. Replacement of the x-ray target caused the 6FFF output to realign with expected trends. Target degradation was uncovered due to a robust quality control trending database and awareness of typical output behaviour. These results demonstrate the importance of data trending to identify component failure and provide centres with knowledge to recognise this potential fault.
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Affiliation(s)
- Chris Hayes
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom.
| | - Raymond B King
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom
| | - Alan R Hounsell
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Jubilee Road, Belfast, Northern Ireland, United Kingdom
| | - Christina E Agnew
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom
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El-Sayed SM, El-Gebaly RH, Fathy MM, Abdelaziz DM. Stereotactic body radiation therapy for prostate cancer: a dosimetric comparison of IMRT and VMAT using flattening filter and flattening filter-free beams. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2024:10.1007/s00411-024-01078-z. [PMID: 38969869 DOI: 10.1007/s00411-024-01078-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 06/14/2024] [Indexed: 07/07/2024]
Abstract
This retrospective study was performed to evaluate plan quality and treatment delivery parameters of stereotactic body radiation therapy (SBRT) for prostate cancer. The study utilized different isocentric modulated techniques: intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) using 6 MV flattening filter (FF) and 10 MV flattening filter-free beams (FFF). Fifteen retrospective prostate cancer patients were selected for this study. Sixty plans were created with an SBRT-prescribed dose of 36.25 Gy delivered in five fractions. Planning target volume (PTV) coverage, plan quality indices, doses delivered to organs at risk (OARs), and treatment delivery parameters were compared for all plans. It turned out that VMAT plans, particularly those using the FFF beam, provided superior target conformality and a steeper dose gradient as compared to IMRT plans. Additionally, VMAT plans showed better OARs sparing compared to IMRT plans. However, IMRT plans delivered a lower maximum dose to the target than VMAT plans. Importantly, the VMAT plans resulted in reduced treatment delivery parameters, including beam on time (BOT), monitor unit (MU), and modulation factor (MF), compared to IMRT plans. Furthermore, a statistically significant difference was observed in BOT and mean body dose between FF and FFF beams, with FFF beams showing superior performance. Considering all results, VMAT using 10 MV (FFF) is suggested for treating prostate cancer patients with SBRT. This offers the fastest delivery in addition to maintaining the highest plan quality.
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Affiliation(s)
- Sherif M El-Sayed
- Biophysics Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
- Radiotherapy Department, Baheya Hospital, Giza, Egypt.
| | - Reem H El-Gebaly
- Biophysics Department, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | - Mohamed M Fathy
- Biophysics Department, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | - Dina M Abdelaziz
- Radiotherapy Department, Baheya Hospital, Giza, Egypt
- Radiotherapy and Nuclear Medicine Department, National Cancer Institute, Cairo, Egypt
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Riis HL, Engstrøm KH, Slama L, Dass J, Ebert MA, Rowshanfarzad P. Assessing focal spot alignment in clinical linear accelerators: a comprehensive evaluation with triplet phantoms. Phys Eng Sci Med 2024:10.1007/s13246-024-01450-9. [PMID: 38954381 DOI: 10.1007/s13246-024-01450-9] [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: 03/04/2024] [Accepted: 05/21/2024] [Indexed: 07/04/2024]
Abstract
A fundamental parameter to evaluate the beam delivery precision and stability on a clinical linear accelerator (linac) is the focal spot position (FSP) measured relative to the collimator axis of the radiation head. The aims of this work were to evaluate comprehensive data on FSP acquired on linacs in clinical use and to establish the ability of alternative phantoms to detect effects on patient plan delivery related to FSP. FSP measurements were conducted using a rigid phantom holding two ball-bearings at two different distances from the radiation source. Images of these ball-bearings were acquired using the electronic portal imaging device (EPID) integrated with each linac. Machine QA was assessed using a radiation head-mounted PTW STARCHECK phantom. Patient plan QA was investigated using the SNC ArcCHECK phantom positioned on the treatment couch, irradiated with VMAT plans across a complete 360° gantry rotation and three X-ray energies. This study covered eight Elekta linacs, including those with 6 MV, 18 MV, and 6 MV flattening-filter-free (FFF) beams. The largest range in the FSP was found for 6 MV FFF. The FSP of one linac, retrofitted with 6 MV FFF, displayed substantial differences in FSP compared to 6 MV FFF beams on other linacs, which all had FSP ranges less than 0.50 mm and 0.25 mm in the lateral and longitudinal directions, respectively. The PTW STARCHECK phantom proved effective in characterising the FSP, while the SNC ArcCHECK measurements could not discern FSP-related features. Minor variations in FSP may be attributed to adjustments in linac parameters, component replacements necessary for beam delivery, and the wear and tear of various linac components, including the magnetron and gun filament. Consideration should be given to the ability of any particular phantom to detect a subsequent impact on the accuracy of patient plan delivery.
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Affiliation(s)
- Hans L Riis
- Department of Oncology, Odense University Hospital, Odense, Denmark.
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
- Radiofysisk Laboratorium, Odense University Hospital, Kløvervænget 19, DK-5000 Odense C, Odense, Denmark.
| | - Kenni H Engstrøm
- Department of Oncology, Odense University Hospital, Odense, Denmark
| | - Luke Slama
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia
| | - Joshua Dass
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia
- Centre for Advanced Technologies in Cancer Research (CATCR), Perth, WA, 6000, Australia
| | - Martin A Ebert
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia
- Centre for Advanced Technologies in Cancer Research (CATCR), Perth, WA, 6000, Australia
- School of Physics, Mathematics, and Computing, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Pejman Rowshanfarzad
- Centre for Advanced Technologies in Cancer Research (CATCR), Perth, WA, 6000, Australia
- School of Physics, Mathematics, and Computing, The University of Western Australia, Crawley, WA, 6009, Australia
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Sun SH, Kollitz E, Tseng WC, Schwarz A, Maloney L, Li J, Liu C, Yan G. MR-linac MLC positioning QA by digitally stitching dual double-exposed films. J Appl Clin Med Phys 2024; 25:e14325. [PMID: 38467039 PMCID: PMC11244661 DOI: 10.1002/acm2.14325] [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: 12/04/2023] [Revised: 01/31/2024] [Accepted: 02/28/2024] [Indexed: 03/13/2024] Open
Abstract
PURPOSE The picket fence (PF) test is highly recommended for multi-leaf collimator (MLC) quality assurance. However, since the electronic portal imaging device (EPID) on the Elekta Unity only covers a small area, it is not feasible to perform the PF test for the entire MLC. Here, we propose a technique for the PF test by stitching two double-exposed films. METHODS Two EBT3 films were used to encompass the entire MLC, with each one covering one half of the area. Two fields were employed to apply double exposure: a PF pattern consisting of 11 2 mm wide pickets and a 2.84 cm x 22 cm open field. The edges of the open field defined by the diaphragms were used to correct film rotation as well as align them horizontally. The PF pattern was also measured with the EPID where the pickets were used to align the films vertically. Individual leaf positions were detected on the merged film for quantitative analysis. Various MLC positioning errors were introduced to evaluate the technique's sensitivity. RESULTS The merged films covered 72 leaf pairs properly (four leaf pairs on both sides were outside the treatment couch). With the EPID, the leaf positioning accuracy was -0.02 ± 0.07 mm (maximum: 0.29 mm) and the picket width variation was 0.00 ± 0.03 mm (maximum: 0.11 mm); with the films, the position accuracy and width variation were -0.03 ± 0.13 mm (maximum: 0.80 mm) and 0.00 ± 0.13 mm (maximum: 0.74 mm), respectively. The EPID was able to detect errors of 0.5 mm or above with submillimeter accuracy; the films were only able to detect errors > 1.0 mm. CONCLUSION We developed a quantitative technique for the PF test on the Elekta Unity. The merged films covered nearly the entire MLC leaf banks. The technique exhibited clinically acceptable accuracy and sensitivity to MLC positioning errors.
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Affiliation(s)
- Sheng-Hsuan Sun
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Erika Kollitz
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Wen-Chih Tseng
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Amanda Schwarz
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Luke Maloney
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Jonathan Li
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Chihray Liu
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
| | - Guanghua Yan
- Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA
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Zhou Y, Liu Y, Chen M, Fang J, Xiao L, Huang S, Qi Z, Deng X, Zhang J, Peng Y. Commissioning and clinical evaluation of a novel high-resolution quality assurance digital detector array for SRS and SBRT. J Appl Clin Med Phys 2024; 25:e14258. [PMID: 38175960 PMCID: PMC11005972 DOI: 10.1002/acm2.14258] [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: 07/08/2023] [Revised: 12/03/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024] Open
Abstract
PURPOSE We aimed to perform the commissioning and clinical evaluation of myQA SRS detector array for patient-specific quality assurance (PSQA) of stereotactic radiosurgery (SRS)/ stereotactic body radiotherapy (SBRT) plans. METHODS To perform the commissioning of myQA SRS, its dose linearity, dose-rate dependence, angular dependence, and field-size dependence were investigated. Ten SBRT plans were selected for clinical evaluation: 1) Common clinical deviations based on the original SBRT plan (Plan0), including multileaf collimator (MLC) positioning deviation and treatment positioning deviation were introduced. 2) Compared the performance of the myQA SRS and a high-resolution EPID dosimetry system in PSQA measurement for the SBRT plans. Evaluation parameters include gamma passing rate (GPR) and distance-to-agreement (DTA) pass rate (DPR). RESULTS The dose linearity, angle dependence, and field-size dependence of myQA SRS system exhibit excellent performance. The myQA SRS is highly sensitive in the detection of MLC deviations. The GPR of (3%/1 mm) decreases from 90.4% of the original plan to 72.7%/62.9% with an MLC outward/inward deviation of 3 mm. Additionally, when the setup error deviates by 1 mm in the X, Y, and Z directions with the GPR of (3%/1 mm) decreasing by an average of -20.9%, -25.7%, and -24.7%, respectively, and DPR (1 mm) decreasing by an average of -33.7%, -32.9%, and -29.8%. Additionally, the myQA SRS has a slightly higher GPR than EPID for PSQA, However, the difference is not statistically significant with the GPR of (3%/1 mm) of (average 90.4%% vs. 90.1%, p = 0.414). CONCLUSION Dosimetry characteristics of the myQA SRS device meets the accuracy and sensitivity requirement of PSQA for SRS/SBRT treatment. The dose rate dependence should be adequately calibrated before its application and a more stringent GPR (3%/1 mm) evaluation criterion is suggested when it is used for SRS/SBRT QA.
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Affiliation(s)
- Yang Zhou
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
- Department of Radiation Oncology, Zhuzhou Hospital Affiliated to Xiangya School of MedicineCentral South UniversityZhuzhouP. R. China
| | - Yimei Liu
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Meining Chen
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Jianlan Fang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Liangjie Xiao
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Shaomin Huang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Zhenyu Qi
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Xiaowu Deng
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Jun Zhang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
| | - Yinglin Peng
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouP. R. China
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Gauter-Fleckenstein B, Schönig S, Mertens L, Oppitz H, Siebenlist K, Ehmann M, Fleckenstein J. Effect of simultaneous integrated boost concepts on photoneutron and distant out-of-field doses in VMAT for prostate cancer. Strahlenther Onkol 2024; 200:219-229. [PMID: 37707518 PMCID: PMC10876496 DOI: 10.1007/s00066-023-02138-x] [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: 04/16/2023] [Accepted: 08/08/2023] [Indexed: 09/15/2023]
Abstract
BACKGROUND A simultaneous integrated boost (SIB) may result in increased out-of-field (DOOF) and photoneutron (HPN) doses in volumetric modulated arc therapy (VMAT) for prostate cancer (PCA). This work therefore aimed to compare DOOF and HPN in flattened (FLAT) and flattening filter-free (FFF) 6‑MV and 10-MV VMAT treatment plans with and without SIB. METHODS Eight groups of 30 VMAT plans for PCA with 6 MV or 10 MV, with or without FF and with uniform (2 Gy) or SIB target dose (2.5/3.0 Gy) prescriptions (CONV, SIB), were generated. All 240 plans were delivered on a slab-phantom and compared with respect to measured DOOF and HPN in 61.8 cm distance from the isocenter. The 6‑ and 10-MV flattened VMAT plans with conventional fractionation (6- and 10-MV FLAT CONV) served as standard reference groups. Doses were analyzed as a function of delivered monitor units (MU) and weighted equivalent square field size Aeq. Pearson's correlation coefficients between the presented quantities were determined. RESULTS The SIB plans resulted in decreased HPN over an entire prostate RT treatment course (10-MV SIB vs. CONV -38.2%). Omission of the flattening filter yielded less HPN (10-MV CONV -17.2%; 10-MV SIB -22.5%). The SIB decreased DOOF likewise by 39% for all given scenarios, while the FFF mode reduced DOOF on average by 60%. A strong Pearson correlation was found between MU and HPN (r > 0.9) as well as DOOF (0.7 < r < 0.9). CONCLUSION For a complete treatment, SIB reduces both photoneutron and OOF doses to almost the same extent as FFF deliveries. It is recommended to apply moderately hypofractionated 6‑MV SIB FFF-VMAT when considering photoneutron or OOF doses.
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Affiliation(s)
- Benjamin Gauter-Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany.
| | - Sebastian Schönig
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Lena Mertens
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Hans Oppitz
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Kerstin Siebenlist
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Michael Ehmann
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Jens Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
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Alterio D, Zaffaroni M, Bossi P, Dionisi F, Elicin O, Falzone A, Ferrari A, Jereczek-Fossa BA, Sanguineti G, Szturz P, Volpe S, Scricciolo M. Reirradiation of head and neck squamous cell carcinomas: a pragmatic approach-part I: prognostic factors and indications to treatment. LA RADIOLOGIA MEDICA 2024; 129:160-173. [PMID: 37731151 DOI: 10.1007/s11547-023-01713-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/25/2023] [Indexed: 09/22/2023]
Abstract
INTRODUCTION Reirradiation (reRT) of locally recurrent/second primary tumors of the head and neck region is a potentially curative treatment for patients not candidate to salvage surgery. Aim of the present study is to summarize available literature on both prognostic factors and indications to curative reRT in this clinical setting. MATERIALS AND METHODS A narrative review of the literature was performed on two topics: (1) patients' selection according to prognostic factors and (2) dosimetric feasibility of reRT. Postoperative reRT and palliative intent treatments were out of the scope of this work. RESULTS Patient-tumor and treatment-related prognostic factors were analyzed, together with dosimetric parameters concerning target volume and organs at risk. Based on available evidence, a stepwise approach has been proposed aiming to provide a useful tool to identify suitable candidates for curative reRT in clinical practice. This was then applied to two clinical cases, proposed at the end of this work. CONCLUSION A second course of RT in head and neck recurrence/second primary tumors is a personalized approach that can be offered to selected patients only in centers with expertise and dedicated equipment following a multidisciplinary team discussion.
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Affiliation(s)
- Daniela Alterio
- Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Mattia Zaffaroni
- Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy.
| | - Paolo Bossi
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy
| | - Francesco Dionisi
- Radiotherapy Unit, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Olgun Elicin
- Department of Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Andrea Falzone
- Unità Operativa Multizonale di Radiologia Ospedale di Rovereto e Arco, Azienda Sanitaria per i Servizi Provinciali di Trento, Trento, Italy
| | - Annamaria Ferrari
- Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Barbara Alicja Jereczek-Fossa
- Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Giuseppe Sanguineti
- Radiotherapy Unit, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Petr Szturz
- Department of Oncology, University of Lausanne (UNIL) and Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Stefania Volpe
- Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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Hearn N, Leppien A, O’Connor P, Cahill K, Atwell D, Vignarajah D, Min M. Radiotherapy dose escalation using pre-treatment diffusion-weighted imaging in locally advanced rectal cancer: a planning study. BJR Open 2024; 6:tzad001. [PMID: 38352181 PMCID: PMC10860507 DOI: 10.1093/bjro/tzad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/14/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024] Open
Abstract
Objectives Diffusion-weighted MRI (DWI) may provide biologically relevant target volumes for dose-escalated radiotherapy in locally advanced rectal cancer (LARC). This planning study assessed the dosimetric feasibility of delivering hypofractionated boost treatment to intra-tumoural regions of restricted diffusion prior to conventional long-course radiotherapy. Methods Ten patients previously treated with curative-intent standard long-course radiotherapy (50 Gy/25#) were re-planned. Boost target volumes (BTVs) were delineated semi-automatically using 40th centile intra-tumoural apparent diffusion coefficient value with expansions (anteroposterior 11 mm, transverse 7 mm, craniocaudal 13 mm). Biased-dosed combined plans consisted of a single-fraction volumetric modulated arc therapy flattening-filter-free (VMAT-FFF) boost (phase 1) of 5, 7, or 10 Gy before long-course VMAT (phase 2). Phase 1 plans were assessed with reference to stereotactic conformality and deliverability measures. Combined plans were evaluated with reference to standard long-course therapy dose constraints. Results Phase 1 BTV dose targets at 5/7/10 Gy were met in all instances. Conformality constraints were met with only 1 minor violation at 5 and 7 Gy. All phase 1 and combined phase 1 + 2 plans passed patient-specific quality assurance. Combined phase 1 + 2 plans generally met organ-at-risk dose constraints. Exceptions included high-dose spillage to bladder and large bowel, predominantly in cases where previously administered, clinically acceptable non-boosted plans also could not meet constraints. Conclusions Targeted upfront LARC radiotherapy dose escalation to DWI-defined is feasible with appropriate patient selection and preparation. Advances in knowledge This is the first study to evaluate the feasibility of DWI-targeted upfront radiotherapy boost in LARC. This work will inform an upcoming clinical feasibility study.
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Affiliation(s)
- Nathan Hearn
- Department of Medical Imaging, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
- Thompson Institute, University of the Sunshine Coast, Birtinya, QLD 4575, Australia
| | - Alexandria Leppien
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
| | - Patrick O’Connor
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
- School of Information Technology and Electrical Engineering, University of Queensland, St Lucia, QLD 4072, Australia
| | - Katelyn Cahill
- Thompson Institute, University of the Sunshine Coast, Birtinya, QLD 4575, Australia
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
| | - Daisy Atwell
- Thompson Institute, University of the Sunshine Coast, Birtinya, QLD 4575, Australia
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
| | - Dinesh Vignarajah
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
- School of Medicine and Dentistry, Griffith University, Sunshine Coast Health Institute, Birtinya, QLD 4575, Australia
| | - Myo Min
- Thompson Institute, University of the Sunshine Coast, Birtinya, QLD 4575, Australia
- Department of Radiation Oncology, Sunshine Coast University Hospital, Birtinya, QLD 4575, Australia
- School of Medicine and Dentistry, Griffith University, Sunshine Coast Health Institute, Birtinya, QLD 4575, Australia
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10
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Kandasamy K, Samuel EJJ. Dosimetric Evaluation of Semiflex Three-dimensional Chamber under Unflatten Beam in Comparison among Different Detectors. J Med Phys 2024; 49:84-94. [PMID: 38828067 PMCID: PMC11141746 DOI: 10.4103/jmp.jmp_115_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: 09/02/2023] [Revised: 02/22/2024] [Accepted: 02/22/2024] [Indexed: 06/05/2024] Open
Abstract
Purpose The goal of this study is to investigate the dosimetric properties of a Semiflex three-dimensional (3D) chamber in an unflatten beam and compare its data from a small to a large field flattening filter-free (FFF) beam with different radiation detectors. Methods The sensitivity, linearity, reproducibility, dose rate dependency, and energy dependence of a Semiflex 3D detector in flattening filter and filter-free beam were fully investigated. The minimum radiation observed field widths for all detectors were calculated using lateral electronic charged particle equilibrium to investigate dosimetric characteristics such as percentage depth doses (PDDs), profiles, and output factors (OPFs) for Semiflex 3D detector under 6FFF Beam. The Semiflex 3D measured data were compared to that of other detectors employed in this study. Results The ion chamber has a dosage linearity deviation of +1.2% for <10 MU, a dose-rate dependency deviation of +0.5%, and significantly poorer sensitivity due to its small volume. There is a difference in field sizes between manufacturer specs and derived field sizes. The measured PDD, profiles, and OPFs of the Semiflex 3D chamber were within 1% of each other for all square field sizes set under linac for the 6FFF beam. Conclusion It was discovered to be an appropriate detector for relative dose measurements for 6 FFF beams with higher dose rates for field sizes more than or equal to 3 cm × 3 cm.
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Affiliation(s)
- Kanakavel Kandasamy
- Department of Physics, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu, India
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11
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Darréon J, Debnath SBC, Benkreira M, Fau P, Mailleux H, Ferré M, Benkemouche A, Tallet A, Annede P, Petit C, Salem N. A novel lung SBRT treatment planning: Inverse VMAT plan with leaf motion limitation to ensure the irradiation reproducibility of a moving target. Med Dosim 2023; 49:159-164. [PMID: 38061915 DOI: 10.1016/j.meddos.2023.11.001] [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: 07/24/2023] [Revised: 10/20/2023] [Accepted: 11/01/2023] [Indexed: 05/08/2024]
Abstract
This study exposed the implementation of a novel technique (VMATLSL) for the planning of moving targets in lung stereotactic body radiation therapy (SBRT). This new technique has been compared to static conformal radiotherapy (3D-CRT), volumetric-modulated arc therapy (VMAT), and dynamic conformal arc (DCA). The rationale of this study was to lower geometric complexity (54.9% lower than full VMAT) and hence ensure the reproducibility of the treatment delivery by reducing the risk for interplay errors induced by respiratory motion. Dosimetry metrics were studied with a cohort of 30 patients. Our results showed that leaf speed limitation provided conformal number (CN) close to the VMAT (median CN of VMATLSL is 0.78 vs 0.82 for full VMAT) and was a significant improvement on 3D-CRT and DCA with segment-weight optimized (respectively 0.55 and 0.57). This novel technique is an alternative to VMAT or DCA for lung SBRT treatments, combining independence from the patient's breathing pattern, from the size and amplitude of the lesion, free from interplay effect, and with dosimetry metrics close to the best that could be achieved with full VMAT.
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Affiliation(s)
- Julien Darréon
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France.
| | | | - Mohamed Benkreira
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Pierre Fau
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Hugues Mailleux
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Marjorie Ferré
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Ahcene Benkemouche
- Département de Physique Médicale, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Agnès Tallet
- Institut Paoli-Calmettes, Service de Radiothérapie, Marseille, 13009, France
| | - Pierre Annede
- Centre de radiothérapie Saint Louis, Croix Rouge Française, Toulon, 83100, France
| | - Claire Petit
- Institut Paoli-Calmettes, Service de Radiothérapie, Marseille, 13009, France
| | - Naji Salem
- Institut Paoli-Calmettes, Service de Radiothérapie, Marseille, 13009, France
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12
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Hui CB, Pourmoghaddas A, Mutaf YD. The effects of flattening filter-free beams and aperture shape controller on the complexity of conventional large-field treatment plans. J Appl Clin Med Phys 2023; 24:e14108. [PMID: 37528683 PMCID: PMC10647973 DOI: 10.1002/acm2.14108] [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: 04/24/2023] [Revised: 06/23/2023] [Accepted: 07/14/2023] [Indexed: 08/03/2023] Open
Abstract
PURPOSE The purpose of this study was to investigate the impact of using flattening filter-free (FFF) beams and the aperture shape controller (ASC) on the complexity of conventional large-field treatment plans. METHODS AND MATERIALS A total of 24 head and neck (H&N) and 24 prostate with pelvic nodes treatment plans were used in this study. Each plan was reoptimized using the original clinical objectives with both flattened and FFF beams, as well as six different ASC settings. The dosimetric qualities of each plan cohort were evaluated using commonly used dose-volume histogram values, and plan complexities were assessed through metrics including monitor unit (MU)/Dose, change in gantry speed, multileaf collimator (MLC) speed, the edge area ratio metric (EM), and the equivalent square length. RESULTS No significant differences in dosimetric qualities were found between plans with flattened and FFF beams. The ASC settings did not have significant effects on dosimetric qualities in the H&N plan cohort, but the "very high" ASC setting resulted in poorer dosimetric results for the prostate plans. Plans with FFF beams had significantly higher MU/Dose compared to plans with flattened beams. The use of flattening filter (FF) had significant effects on the change in gantry speed, with flattened beams producing plans that required higher change in gantry speed. However, the FF did not have significant effects on MLC speed, EM, or equivalent square length. In contrast, ASC settings had significant effects on these three metrics; increasing the ASC level resulted in plans with decreasing MLC speed, lower edge area ratio, and higher equivalent square length. CONCLUSION This study demonstrated that using FFF beams with various ASC settings, except for the "very high" level, can produce plans with reduced complexities without compromising dosimetric qualities in conventional large-field treatment plans.
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Affiliation(s)
- Cheukkai B. Hui
- Department of Radiation OncologyKaiser PermanenteDublinCaliforniaUSA
| | | | - Yildirim D. Mutaf
- Department of Radiation OncologyKaiser PermanenteDublinCaliforniaUSA
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13
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Pokhrel D, Mallory R, Bernard ME, Kudrimoti M. How much rotational error is clinically acceptable for single-isocenter/two-lesion lung SBRT treatment on halcyon ring delivery system (RDS)? J Appl Clin Med Phys 2023:e14068. [PMID: 37311070 DOI: 10.1002/acm2.14068] [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: 11/11/2022] [Revised: 05/17/2023] [Accepted: 05/28/2023] [Indexed: 06/15/2023] Open
Abstract
PURPOSE SBRT treatment of two separate lung lesions via single-isocenter/multi-target (SIMT) plan on Halcyon RDS could improve patient comfort, compliance, patient throughput, and clinic efficiency. However, aligning two separate lung lesions synchronously via a single pre-treatment CBCT scan on Halcyon can be difficult due to rotational patient setup errors. Thus, to quantify the dosimetric impact, we simulated loss of target(s) coverage due to small, yet clinically observable rotational patient setup errors on Halcyon for SIMT treatments. METHODS Seventeen previously treated 4D-CT based SIMT lung SBRT patients with two separate lesions (total 34 lesions, 50 Gy in five fractions to each lesion) on TrueBeam (6MV-FFF) were re-planned on Halcyon (6MV-FFF) using a similar arc geometry (except couch rotation), dose engine (AcurosXB algorithm), and treatment planning objectives. Rotational patient setup errors of [± 0.5⁰ to ± 3.0⁰] on Halcyon were simulated via Velocity registration software in all three rotation axes and recalculated dose distributions in Eclipse treatment planning system. Dosimetric impact of rotational errors was evaluated for target coverage and organs at risk (OAR). RESULTS Average PTV volume and distance to isocenter were 23.7 cc and 6.1 cm. Average change in Paddick's conformity indexes were less than -5%, -10%, and -15% for 1°, 2°, and 3°, respectively for yaw, roll, and pitch rotation directions. Maximum drop off of PTV(D100%) coverage for 2° rotation was -2.0% (yaw), -2.2% (roll), and -2.5% (pitch). With ±1° rotational error, no PTV(D100%) loss was found. Due to anatomical complexity: irregular and highly variable tumor sizes and locations, highly heterogenous dose distribution, and steep dose gradient, no trend for loss of target(s) coverage as a function of distance to isocenter and PTV size was found. Change in maximum dose to OAR were acceptable per NRG-BR001 within ±1.0° rotation, but were up to 5 Gy higher to heart with 2° in the pitch rotation axis. CONCLUSION Our clinically realistic simulation results show that rotational patient setup errors up to 1.0° in any rotation axis could be acceptable for selected two separate lung lesions SBRT patients on Halcyon. Multivariable data analysis in large cohort is ongoing to fully characterize Halcyon RDS for synchronous SIMT lung SBRT.
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Affiliation(s)
- Damodar Pokhrel
- Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Richard Mallory
- Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mark E Bernard
- 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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McDermott PN, Drake D, Knill C, Sigler MD. Linac primary barrier transmission: Flattening filter free and field size dependence. J Appl Clin Med Phys 2023; 24:e13886. [PMID: 36601672 PMCID: PMC10018660 DOI: 10.1002/acm2.13886] [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: 07/18/2022] [Revised: 11/08/2022] [Accepted: 12/15/2022] [Indexed: 01/06/2023] Open
Abstract
There is widespread consensus in the literature that flattening filter free (FFF) beams have a lower primary barrier transmission than flattened beams. Measurements presented here, however, show that for energy compensated FFF beams, the barrier transmission can be as much as 70% higher than for flattened beams. The ratio of the FFF barrier transmission to the flattened beam barrier transmission increases with increasing barrier thickness. The use of published FFF TVL data for energy compensated FFF beams could lead to an order of magnitude underestimate of the air kerma rate. There are little data in the literature on the field size dependence of the barrier transmission for flattened beams. Barrier transmission depends on the field size at the barrier, not at isocenter Measurements are presented showing the relative dependence of barrier transmission on the field size, measured at the barrier, for 6 MV and 10 MV beams. An analytical fitting formula is provided for the field size dependence. For field sizes greater than about 150 cm in side length, the field size dependence is minimal. For field sizes less than about 100 cm, the transmission declines rapidly as the field size decreases.
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Affiliation(s)
| | | | - Cory Knill
- Beaumont Health System, Dearborn, Michigan, USA
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15
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Hermida-López M, García-Relancio D, Comino-Muriano M, Pérez-Esteve B, Castillo-Elías E, Carrera-García Y, Giralt J. Treatment time of image-guided radiotherapy with a Halcyon 2.0 system. J Med Imaging Radiat Sci 2023; 54:117-122. [PMID: 36535858 DOI: 10.1016/j.jmir.2022.12.002] [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: 08/25/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022]
Abstract
INTRODUCTION The treatment fraction time is a key indicator of the external beam radiotherapy process. The Halcyon system was designed to improve the clinical workflow, according to the manufacturer (Varian Medical Systems). Few works studied the actual delivery efficiency of the Halcyon system. This work analyzed the treatment time on a Halcyon 2.0 unit for a variety of sites along a period of 9 months. MATERIALS AND METHODS Treatment time included patient setup, image acquisition, image-guided online couch correction, and radiation delivery time. Data were extracted from the ARIA oncology information system and were studied as a function of the treatment site, the delivery modality, and the time from the first day of treatments with the Halcyon 2.0 system in our institution. RESULTS A total of 8599 fractions were delivered during the analyzed period (69.5% from VMAT plans, and 30.5% from IMRT plans). The number of fractions by site ranged from 30 for anal canal to 1933 for prostate. Five sites (prostate, lung, pelvis with prostate, breast, and gynecological sites) accounted for the 84% of the fractions. After a 2-week adaptation period of the staff, the daily mean treatment time was reduced to less than 12 min. The mean treatment time of all the fractions amounted to 10.5 ± 3.8 min. CONCLUSIONS The Halcyon 2.0 allowed delivering online image-guided radiation therapy in all fractions with total treatment time consistently below the 12-min standard time slot, for most of the analyzed treatment sites.
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Affiliation(s)
- Marcelino Hermida-López
- Servei de Fisica i Protecció Radiològica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain.
| | - David García-Relancio
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Marina Comino-Muriano
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Brenda Pérez-Esteve
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Esther Castillo-Elías
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Yolanda Carrera-García
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Jordi Giralt
- Servei d'Oncologia Radioteràpica, Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
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Lin CY, Chou LS, Wu YH, Kuo JS, Mehta MP, Shiau AC, Liang JA, Hsu SM, Wang TH. Developing an AI-assisted planning pipeline for hippocampal avoidance whole brain radiotherapy. Radiother Oncol 2023; 181:109528. [PMID: 36773828 DOI: 10.1016/j.radonc.2023.109528] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/04/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023]
Abstract
BACKGROUND AND PURPOSE Hippocampal avoidance whole brain radiotherapy (HA-WBRT) is effective for controlling disease and preserving neuro-cognitive function for brain metastases. However, contouring and planning of HA-WBRT is complex and time-consuming. We designed and evaluated a pipeline using deep learning tools for a fully automated treatment planning workflow to generate HA-WBRT radiotherapy plans. MATERIALS AND METHODS We retrospectively collected 50 adult patients who received HA-WBRT. Using RTOG- 0933 clinical trial protocol guidelines, all organs-at-risk (OARs) and the clinical target volume (CTV) were contoured by experienced radiation oncologists. A deep-learning segmentation model was designed and trained. Next, we developed a volumetric-modulated arc therapy (VMAT) auto-planning algorithm for 30 Gy in 10 fractions. Automated segmentations were evaluated using the Dice similarity coefficient (DSC) and 95th-percentile Hausdorff distance (95 % HD). Auto-plans were evaluated by the percentage of PTV volume that receives 30 Gy (V30Gy), conformity index (CI), and homogeneity index (HI) of planning target volume (PTV) and the minimum dose (D100%) and maximum dose (Dmax) for the hippocampus, Dmax for the lens, eyes, optic nerve, brain stem, and chiasm. RESULTS We developed a deep-learning segmentation model and an auto-planning script. For the 10 cases in the independent test set, the overall average DSC and 95 % HD of contours were greater than 0.8 and less than 7 mm, respectively. All auto-plans met the RTOG- 0933 criteria. The HA-WBRT plan automatically created time was about 10 min. CONCLUSIONS An artificial intelligence (AI)-assisted pipeline using deep learning tools can rapidly and accurately generate clinically acceptable HA-WBRT plans with minimal manual intervention and increase efficiency of this treatment for brain metastases.
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Affiliation(s)
- Chih-Yuan Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; Medical Physics and Radiation Measurements Laboratory, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Lin-Shan Chou
- Division of Radiation Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yuan-Hung Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; Medical Physics and Radiation Measurements Laboratory, National Yang Ming Chiao Tung University, Taipei, Taiwan; Division of Radiation Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - John S Kuo
- Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan; Department of Neurosurgery, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Minesh P Mehta
- Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, Florida, USA; Florida International University, Miami, Florida, USA
| | - An-Cheng Shiau
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan; Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan
| | - Ji-An Liang
- Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan; Department of Medicine, China Medical University, Taichung, Taiwan
| | - Shih-Ming Hsu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; Medical Physics and Radiation Measurements Laboratory, National Yang Ming Chiao Tung University, Taipei, Taiwan.
| | - Ti-Hao Wang
- Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan.
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Stepanek CJ, Haynes JA, Fletcher S. Evaluation of a complementary metal oxide semiconductor detector as a tool for stereotactic body radiotherapy plan quality assurance. Phys Imaging Radiat Oncol 2023; 25:100418. [PMID: 36755894 PMCID: PMC9900433 DOI: 10.1016/j.phro.2023.100418] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Background and purpose A sub-mm resolution Complementary Metal Oxide Semiconductor sensor has been developed for stereotactic radiotherapy quality assurance. Herein we evaluate its basic dosimetric performance and its application for linac C-arm stereotactic body radiotherapy (SBRT) plan quality assurance. Materials and methods The detector was integrated into its accompanying phantom or in Water Equivalent Plastic (WEP). The measurement reproducibility, stability, dose linearity and dependence on angularity, dose rate and field size were investigated. Clinical plan measurements were compared to our radiotherapy treatment planning system and radiochromic film. Sensitivity to introduced Multi Leaf Collimator (MLC) offsets was evaluated by simulating single MLC offsets in SBRT plans and comparing measurements to expected doses. Results Signal reproducibility was within ± 0.1 % and output calibration was stable over a 6 month period. Detector showed good linearity with dose (r2 = 1). Signal decreased by 5 % when dose rate was decreased from 1300 MU/min to 300 MU/min. Output factors agreed within 0.5 % of chamber measurements for 1x1 cm field sizes or greater. Angularity measurements showed good agreement with reference. For measurement of planned clinical doses, gamma pass-rates were 98.5 % ± 2.3 % (treatment planning system reference, 2 %/2mm) and 99.2 % ± 1.0 % (film reference, 2 %,2mm). The detector also showed sensitivity to errors of 1 mm offsets in MLC positioning. Conclusion The detector performed well when used for pre-treatment SBRT plan quality assurance, offering a good alternative to radiochromic film.
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Alexander DA, Certa O, Haertter A, Li T, Taunk N, Zhu TC. Comparison of surface dose during whole breast radiation therapy on Halcyon and TrueBeam using Cherenkov imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12371:1237108. [PMID: 37101538 PMCID: PMC10128868 DOI: 10.1117/12.2652588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
The emergence of the Halcyon linear accelerator has allowed for increased patient throughput and improved treatment times for common treatment sites in radiation oncology. However, it has been shown that this can lead to increased surface dose in sites like breast cancer compared with treatments on conventional machines with flattened radiation beams. Cherenkov imaging can be used to estimate surface dose by detection of Cherenkov photons emitted in proportion to energy deposition from high energy electrons in tissue. Phantom studies were performed with both square beams in reference conditions and with clinical treatments, and dosimeter readings and Cherenkov images report higher surface dose (25% for flat phantom entrance dose, 5.9% for breast phantom treatment) from Halcyon beam deliveries than for equivalent deliveries from a TrueBeam linac. Additionally, the first Cherenkov images of a patient treated with Halcyon were acquired, and superficial dose was estimated.
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Affiliation(s)
- Daniel A. Alexander
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Olivia Certa
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Allison Haertter
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Taoran Li
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Neil Taunk
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
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The Study of Dosimetric Characteristics of the XHA600D Medical Linear Accelerator Based on a Monte Carlo Code. SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS 2022. [DOI: 10.1155/2022/7712498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
By investigating the influence of initial electrons on dosimetric characteristics, reasonable incident electron parameters for the nominal 6 MV photon beam of the XHA600D accelerator are finally established, i.e., a 6 MeV monoenergetic electron beam with a radial intensity FWHM of 2.5 mm and an angular divergency of 0.15°. Based on reasonable initial parameters, Percentage Depth Doses (PDDs), Off-Axis Ratios (OARs), total scatter factors, beam qualities, and penumbra widths of both flatteningfilter (FF) and flattening-filter-free (FFF) beams for fields ranging from 4 × 4 to 30 × 30 cm2 are simulated systematically with EGSnrc codes. Not only the simulated dosimetric properties are in excellent agreement with the measurements, but also the dosimetric discrepancies between FF and FFF beams are consistent with the laws of previous studies on other accelerators. Therefore, reasonable incident electron parameters are able to accurately verify the performance of the XHA600D accelerator and can be used for further dosimetry research.
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Thrower S, Prajapati S, Holmes S, Schüler E, Beddar S. Characterization of the Plastic Scintillator Detector System Exradin W2 in a High Dose Rate Flattening-Filter-Free Photon Beam. SENSORS (BASEL, SWITZERLAND) 2022; 22:6785. [PMID: 36146135 PMCID: PMC9505273 DOI: 10.3390/s22186785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/02/2022] [Accepted: 09/04/2022] [Indexed: 06/16/2023]
Abstract
(1) Background: The Exradin W2 is a commercially available scintillator detector designed for reference and relative dosimetry in small fields. In this work, we investigated the performance of the W2 scintillator in a 10 MV flattening-filter-free photon beam and compared it to the performance of ion chambers designed for small field measurements. (2) Methods: We measured beam profiles and percent depth dose curves with each detector and investigated the linearity of each system based on dose per pulse (DPP) and pulse repetition frequency. (3) Results: We found excellent agreement between the W2 scintillator and the ion chambers for beam profiles and percent depth dose curves. Our results also showed that the two-voltage method of calculating the ion recombination correction factor was sufficient to correct for the ion recombination effect of ion chambers, even at the highest DPP. (4) Conclusions: These findings show that the W2 scintillator shows excellent agreement with ion chambers in high DPP conditions.
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Affiliation(s)
- Sara Thrower
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Surendra Prajapati
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Medical Physics Program, The University of Texas MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | | | - Emil Schüler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Medical Physics Program, The University of Texas MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Sam Beddar
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Medical Physics Program, The University of Texas MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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Monte Carlo computation of photon energy spectra in central axis of flattened and unflattened beams and doses in critical organs in a water phantom model of prostate radiotherapy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Fetal dose estimation for Virtual Tangential-fields Arc Therapy whole breast irradiation by optically stimulated luminescence dosimeters. Phys Med 2022; 101:44-49. [PMID: 35944444 DOI: 10.1016/j.ejmp.2022.07.007] [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: 12/17/2021] [Revised: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 11/21/2022] Open
Abstract
Breast cancer is the most frequently diagnosed tumor in pregnant women and radiation therapy should carefully be weighted up because of the dose to the fetus. The aim of this study was to investigate fetal dose in a patient treated with Virtual Tangential-fields Arc Therapy (ViTAT), an innovative technique for whole breast irradiation. Optically stimulated luminescence detectors (OSLDs) were calibrated on a Varian TrueBeam linac, with both a 6X and 6XFFF beam quality, and used for out-of-field measurements. Fetal dose related with ViTAT technique was compared to the standard 3D conformal radiation therapy technique (3DCRT). The fetal dose delivered with a ViTAT technique planned with 6XFFF beam was also investigated. Measurements were taken on a phantom composed of Rando Alderson Phantom slices and solid water slabs. OSLDs were placed in a region identified by the height of the fundus from conception to the twentieth week using a custom made PMMA grid. Due to the higher number of monitor units, the peripheral dose of ViTAT delivered with 6X beams is higher than that of 3DCRT. However, nanoDots measurements prove that ViTAT can be used in place of 3DCRT while maintaining similar fetal dose levels if 6XFFF beams are used.
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IBA myQA SRS Detector for CyberKnife Robotic Radiosurgery Quality Assurance. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12157791] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The IBA myQA® SRS high-resolution solid-state detector was evaluated in the context of robotic radiosurgery delivered using CyberKnife®. The performance was investigated for periodic machine delivery quality assurance (DQA) and patient-specific treatment verification. myQA® SRS is a 140 × 120 mm CMOS matrix with 400 µm resolution, allocated in a cylindrical ABS phantom topped by a hemispheric cap. Evaluations included: periodic DQA tests, angular response, dose-rate dependence and Iris variable aperture collimator field size measurements. For patient-specific QA various intracranial targets were studied (Gamma Index, 3%/1 mm agreement criteria), taking into account also the detector’s angular response. Results for periodic DQA were in accordance with the machine commissioning data. Dose-rate dependence was confirmed, and angular response tests resulted in a signal decay >5% when beams were delivered outside a ±50° amplitude cone with respect to the vertical direction. Concerning patient-specific QA, >50° angled beams elimination led to a Gamma Index passing rates improvement ranging between +3% and +115%. IBA myQA® SRS proved to be a suitable device for many CyberKnife® constancy DQA checks, providing high-resolution real-time results. Patient-specific Gamma tests showed high passing rates once angular dependence corrections were performed, even in high complexity treatments such as those for trigeminal neuralgia targets.
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Kuah T, Vellayappan BA, Makmur A, Nair S, Song J, Tan JH, Kumar N, Quek ST, Hallinan JTPD. State-of-the-Art Imaging Techniques in Metastatic Spinal Cord Compression. Cancers (Basel) 2022; 14:cancers14133289. [PMID: 35805059 PMCID: PMC9265325 DOI: 10.3390/cancers14133289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 12/23/2022] Open
Abstract
Metastatic Spinal Cord Compression (MSCC) is a debilitating complication in oncology patients. This narrative review discusses the strengths and limitations of various imaging modalities in diagnosing MSCC, the role of imaging in stereotactic body radiotherapy (SBRT) for MSCC treatment, and recent advances in deep learning (DL) tools for MSCC diagnosis. PubMed and Google Scholar databases were searched using targeted keywords. Studies were reviewed in consensus among the co-authors for their suitability before inclusion. MRI is the gold standard of imaging to diagnose MSCC with reported sensitivity and specificity of 93% and 97% respectively. CT Myelogram appears to have comparable sensitivity and specificity to contrast-enhanced MRI. Conventional CT has a lower diagnostic accuracy than MRI in MSCC diagnosis, but is helpful in emergent situations with limited access to MRI. Metal artifact reduction techniques for MRI and CT are continually being researched for patients with spinal implants. Imaging is crucial for SBRT treatment planning and three-dimensional positional verification of the treatment isocentre prior to SBRT delivery. Structural and functional MRI may be helpful in post-treatment surveillance. DL tools may improve detection of vertebral metastasis and reduce time to MSCC diagnosis. This enables earlier institution of definitive therapy for better outcomes.
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Affiliation(s)
- Tricia Kuah
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Correspondence: ; Tel.: +65-6779-5555
| | - Balamurugan A. Vellayappan
- Department of Radiation Oncology, National University Cancer Institute Singapore, National University Hospital, Singapore 119074, Singapore;
| | - Andrew Makmur
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| | - Shalini Nair
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
| | - Junda Song
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
| | - Jiong Hao Tan
- University Spine Centre, Department of Orthopaedic Surgery, National University Health System, 1E Lower Kent Ridge Road, Singapore 119228, Singapore; (J.H.T.); (N.K.)
| | - Naresh Kumar
- University Spine Centre, Department of Orthopaedic Surgery, National University Health System, 1E Lower Kent Ridge Road, Singapore 119228, Singapore; (J.H.T.); (N.K.)
| | - Swee Tian Quek
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| | - James Thomas Patrick Decourcy Hallinan
- Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; (A.M.); (S.N.); (J.S.); (S.T.Q.); (J.T.P.D.H.)
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
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Pokhrel D, Mallory R, Bush M, St Clair W, Bernard ME. Feasibility Study of Stereotactic Radiosurgery Treatment of Glomus Jugulare Tumors via HyperArc VMAT. Med Dosim 2022; 47:307-311. [PMID: 35717426 DOI: 10.1016/j.meddos.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 03/08/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
Abstract
This study aims to report on the clinical validation and feasibility of utilizing a novel fully automated treatment planning and delivery system, HyperArc VMAT stereotactic radiosurgery (SRS) for glomus jugulare tumors (GJT). Independent dose verification of the HyperArc module via the MD Anderson's SRS head phantom irradiation and credentialing results showed compliance with the SRS treatment requirements per IROC MD Anderson's standard. Following the Alliance clinical trial, AAPM, RTOG protocols, and QUENTAC requirements, utilizing selected three-partial arc geometry of HyperArc module on TrueBeam Linac with 6MV-FFF beam, GJT SRS plans were generated for nine previously treated Gamma Knife (GK) radiosurgery patients using advanced Acuros-based algorithm to account for tissue inhomogeneity corrections and frameless immobilization with Q-fix mask and Encompass device insert. HyperArc VMAT produced highly conformal SRS dose distributions to GJT, a steep dose gradient around the GJT, and spared adjacent critical organs including the spinal cord (< 3.0 Gy). Due to faster patient setup and less MLC modulation through the target (average beam-on time, 6.2 minutes), the HyperArc VMAT plan can deliver a single high-dose of 18 Gy to the GJT in less than 15 minutes overall treatment time, significantly improving patient comfort and clinic workflow. Pretreatment portal dosimetry quality assurance results and independent dose verification via Monte Carlo-based physics second check met our clinical SRS protocol's requirements for treatment. Due to the highly conformal dose distribution, rapid dose fall-off, excellent sparing of adjacent critical organs, and highly precise and accurate treatment, clinical implementation of frameless HyperArc VMAT for GJT patients who may not have access to nor tolerate frame-based GK SRS treatment are underway.
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Affiliation(s)
- Damodar Pokhrel
- Department of Radiation Medicine, University of Kentucky, Lexington KY, 40536, USA.
| | - Richard Mallory
- Department of Radiation Medicine, University of Kentucky, Lexington KY, 40536, USA
| | - Matthew Bush
- Department of Otolaryngology - Head and Neck Surgery, University of Kentucky, Lexington KY, 40536, USA
| | - William St Clair
- Department of Radiation Medicine, University of Kentucky, Lexington KY, 40536, USA
| | - Mark E Bernard
- Department of Radiation Medicine, University of Kentucky, Lexington KY, 40536, USA
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Evaluation of SRS MapCHECK with StereoPHAN phantom as a new pre-treatment system verification for SBRT plans. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2022. [DOI: 10.2478/pjmpe-2022-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Introduction: The aim of this study was to evaluate the new 2-Dimensional diode array SRS MapCHECK (SunNuclear, Melbourne, USA) with dedicated phantom StereoPHAN (SunNuclear, Melbourne, USA) for the pre-treatment verification of the stereotactic body radiotherapy (SBRT).
Material and methods: For the system, the short and mid-long stability, dose linearity with MU, angular dependence, and field size dependence (ratio of relative output factor) were measured. The results of verification for 15 pre-treatment cancer patients (5 brains, 5 lungs, and 5 livers) performed with SRS MapCHECK and EBT3 Gafchromic films were compared. All the SBRT plans were optimized with the Eclipse (v. 15.6, Varian, Palo Alto, USA) treatment planning system (TPS) using the Acuros XB (Varian, Palo Alto, USA) dose calculation algorithm and were delivered to the Varian EDGE® (Varian, Palo Alto, USA) accelerator equipped with a high-definition multileaf collimator. The 6MV flattening-filter-free beam (FFF) was used.
Results: Short and mid-long stability of SRS MapCHECK was very good (0.1%-0.2%), dose linearity with MU and dependence of the response of the detector on field size results were also acceptable (for dose linearity R2 = 1 and 6% difference between microDiamond and SRS MapCHECK response for the smallest field of 1 × 1 cm2). The angular dependence was very good except for the angles close to 90° and 270°. For pre-treatment plan verification, the gamma method was used with the criteria of 3% dose difference and 3 mm distance to agreement (3%/3 mm), and 2%/2 mm, 1%/1 mm, 3%/1 mm, and 2%/1 mm. The highest passing rate for all criteria was observed on the SRS MapCHECK system.
Conclusions: It is concluded that SRS MapCHECK with StereoPHAN has sufficient potential for pre-treatment verification of the SBRT plans, so that verification of stereotactic plans can be significantly accelerated.
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Quantification of Nanoscale Dose Enhancement in Gold Nanoparticle-Aided External Photon Beam Radiotherapy. Cancers (Basel) 2022; 14:cancers14092167. [PMID: 35565296 PMCID: PMC9102439 DOI: 10.3390/cancers14092167] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 01/27/2023] Open
Abstract
The recent progress in Nanotechnology has introduced Gold Nanoparticles (AuNPs) as promising radiosensitizing agents in radiation oncology. This work aims to estimate dose enhancement due to the presence of AuNPs inside an irradiated water region through Monte Carlo calculations. The GATE platform was used to simulate 6 MV photon histories generated from a TrueBeam® linear accelerator with and without a Flattening Filter (FF) and model AuNPs clusters. The AuNPs size, concentration and distribution pattern were examined. To investigate different clinical irradiation conditions, the effect of field size, presence of FF and placement of AuNPs in water were evaluated. The range of Dose Enhancement Factors (DEF = DoseAu/DoseWater) calculated in this study is 0.99 ± 0.01-1.26 ± 0.02 depending on photon beam quality, distance from AuNPs surface, AuNPs size and concentration and pattern of distribution. The highest DEF is reported for irradiation using un-flattened photon beams and at close distances from AuNPs. The obtained findings suggest that dose deposition could be increased in regions that represent whole cells or subcellular targets (mitochondria, cell nucleus, etc.). Nevertheless, further and consistent research is needed in order to make a step toward AuNP-aided radiotherapy in clinical practice.
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Farr J, Grilj V, Malka V, Sudharsan S, Schippers M. Ultra‐High dose rate radiation production and delivery systems intended for FLASH. Med Phys 2022; 49:4875-4911. [PMID: 35403262 PMCID: PMC9544515 DOI: 10.1002/mp.15659] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 02/21/2022] [Accepted: 03/15/2022] [Indexed: 11/05/2022] Open
Abstract
Higher dose rates, a trend for radiotherapy machines, can be beneficial in shortening treatment times for radiosurgery and mitigating the effects of motion. Recently, even higher doses (e.g., 100 times greater) have become targeted because of their potential to generate the FLASH effect (FE). We refer to these physical dose rates as ultra‐high (UHDR). The complete relationship between UHDR and the FE is unknown. But UHDR systems are needed to explore the relationship further and to deliver clinical UHDR treatments, where indicated. Despite the challenging set of unknowns, the authors seek to make reasonable assumptions to probe how existing and developing technology can address the UHDR conditions needed to provide beam generation capable of producing the FE in preclinical and clinical applications. As a preface, this paper discusses the known and unknown relationships between UHDR and the FE. Based on these, different accelerator and ionizing radiation types are then discussed regarding the relevant UHDR needs. The details of UHDR beam production are discussed for existing and potential future systems such as linacs, cyclotrons, synchrotrons, synchrocyclotrons, and laser accelerators. In addition, various UHDR delivery mechanisms are discussed, along with required developments in beam diagnostics and dose control systems.
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Affiliation(s)
- Jonathan Farr
- Applications of Detectors and Accelerators to Medicine Meyrin 1217 Switzerland
| | - Veljko Grilj
- Lausanne University Hospital Lausanne 1011 Switzerland
| | - Victor Malka
- Weizmann Institute of Science Rehovot 7610001 Israel
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Yang B, Tang KK, Huang CY, Geng H, Lam WW, Wong YS, Tse MY, Lau KK, Cheung KY, Yu SK. Out-of-field dose and its constituent components for a 1.5 T MR-Linac. Phys Med Biol 2021; 66. [PMID: 34700308 DOI: 10.1088/1361-6560/ac3346] [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: 08/07/2021] [Accepted: 10/26/2021] [Indexed: 11/11/2022]
Abstract
This study aims to quantify the relative contributions of phantom scatter, collimator scatter and head leakage to the out-of-field doses (OFDs) of both static fields and clinical intensity-modulated radiation therapy (IMRT) treatments in a 1.5 T MR-Linac. The OFDs of static fields were measured at increasing distances from the field edge in an MR-conditional water phantom. Inline scans at depths of dmax (14 mm), 50 and 100 mm were performed for static fields of 5 × 5, 10 × 10 and 15 × 15 cm2under three different conditions: full scatter, with phantom scatter prevented, and head leakage only. Crossline scans at isocenter and offset positions were performed in full scatter condition. EBT3 radiochromic films were placed at 100 mm depth of solid water phantom to measure the OFD of clinical IMRT plans. All water tank data were normalized to Dmax of a 10 × 10 cm2field and the film results were presented as a fraction of the target mean dose.The OFD in the inline direction varied from 3.5% (15 × 15 cm2, 100 mm depth, 50 mm distance) to 0.014% (5 × 5 cm2, dmax, 400 mm distance). For all static fields, the collimator scatter was higher than the phantom scatter and head leakage at a distance of 100-400 mm. Head leakage remained the smallest among the three components, except at long distances (>375 mm) with small field size. Compared to the inline scans, the crossline scans at the isocenter showed higher doses at distances longer than 80 mm. All crossline profiles at longitudinal offset positions showed a cone shape with laterally shifted maxima. The OFD of IMRT deliveries varied with different target size. For prostate stereotactic body radiation therapy (SBRT) treatment, the OFD decreased from 2% to 0.03% at a distance of 50-500 mm. The OFDs have been measured for a 1.5 T MR-Linac. The presented dosimetric data are valuable for radiation safety assessments on patients treated with the MR-Linac, such as evaluating carcinogenic risk and radiation exposure to cardiac implantable electronic devices.
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Affiliation(s)
- Bin Yang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Ka Keung Tang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Chen-Yu Huang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Hui Geng
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Wai Wang Lam
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Yeung Sum Wong
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Mei Yan Tse
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Ka Ki Lau
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Kin Yin Cheung
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Siu Ki Yu
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
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Thongsawad S, Chanton T, Saiyo N, Udee N. Planar EPID-Based Dosimetry for SRS and SRT Patient-Specific QA. Life (Basel) 2021; 11:life11111159. [PMID: 34833035 PMCID: PMC8624341 DOI: 10.3390/life11111159] [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: 07/08/2021] [Revised: 09/08/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022] Open
Abstract
The study’s purpose was to develop and validate Electronic Portal Imaging Device (EPID)-based dosimetry for Stereotactic Radiosurgery (SRS) and Stereotactic Radiation Therapy (SRT) patient-specific Quality Assurance (QA). The co-operation between extended Source-to-Imager Distance (SID) to reduce the saturation effect and simplify the EPID-based dosimetry model was used to perform patient-specific QA in SRS and SRT plans. The four parameters were included for converting the image to dose at depth 10 cm; dose-response linearity with MU, beam profile correction, collimator scatter and water kernel. The model accuracy was validated with 10 SRS/SRT plans. The traditional diode arrays with MapCHECK were also used to perform patient-specific QA for assuring model accuracy. The 150 cm-SID was found a possibility to reduce the saturation effect. The result of model accuracy was found good agreement between our EPID-based dosimetry and TPS calculation with GPR more than 98% for gamma criteria of 3%/3 mm, more than 95% for gamma criteria of 2%/2 mm, and the results related to the measurement with MapCHECK. This study demonstrated the method to perform SRT and SRT patient-specific QA using EPID-based dosimetry in the FFF beam by co-operating between the extended SID that can reduce the saturation effect and estimate the planar dose distribution with the in-house model.
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Affiliation(s)
- Sangutid Thongsawad
- Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok 10210, Thailand
- Department of Radiation Oncology, Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok 10210, Thailand;
- Correspondence:
| | - Tadchapong Chanton
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand; (T.C.); (N.U.)
| | - Nipon Saiyo
- Department of Radiation Oncology, Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok 10210, Thailand;
- Faculty of Health Science Technology, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok 10210, Thailand
| | - Nuntawat Udee
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand; (T.C.); (N.U.)
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McAloney J, Biggs S, Sobolewski M. Linac reported steering error insensitive to 6 MV FFF transverse beam position deviations. Phys Eng Sci Med 2021; 44:1377-1382. [PMID: 34694587 DOI: 10.1007/s13246-021-01067-2] [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: 05/26/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022]
Abstract
Clinically significant beam position deviations were observed for a 6 MV FFF beam during patient specific QA on an Elekta linear accelerator. There was no significant reported transverse steering error from the machine ion chamber, and routine linac QA practices, including cardinal angle Winston-Lutz test, did not identify the deviations. Subsequent investigation using an electronic portal imaging device (EPID) revealed clinically significant beam position deviations for small steering errors. This prompted investigation into further impact and possible solutions. Testing set-points were established by adjusting transverse steering current to achieve introduced 2 T steering errors. Tests at each set-point included scanning water tank profiles and EPID images. A proposed method for adjusting the 2 T error sensitivity was tested via adjusting the 2 T loop parameter such that a reported error corresponds to specific beam position deviations. The testing set-points resulted in positional deviations of greater than 3 mm for reported errors of less than 1. A new method for improving 2 T error sensitivity was implemented. This work has shown that existing vendor protocol for establishing beam steering error for 6 MV FFF beams can lead to beam position deviations without machine interlocks or significant reported steering errors. Thus, an alternative method of establishing steering error sensitivity based on positional deviations is presented.
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Affiliation(s)
| | | | - Matthew Sobolewski
- Riverina Cancer Care Centre, Wagga Wagga, Australia.,Northern Beaches Cancer Care, Frenchs Forest, Australia
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Takakusagi Y, Usui K, Mizoguchi N, Nagatsuka J, Hikage T, Kodama Y, Ezura T, Kusunoki T, Oizumi Y. Comparison of Moderate Hypofractionated Volumetric-Modulated Arc Therapy Plans With and Without Flattening Filter for Localized Prostate Cancer. Cureus 2021; 13:e18034. [PMID: 34671522 PMCID: PMC8520568 DOI: 10.7759/cureus.18034] [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] [Accepted: 09/16/2021] [Indexed: 12/24/2022] Open
Abstract
Background/Aim The aim of this study was to compare volumetric-modulated arc therapy (VMAT) radiation plans between conventional VMAT with flattening filter (cFF-VMAT) and flattening filter-free VMAT (FFF-VMAT) for localized prostate cancer. Materials and methods Ten patients with localized prostate cancer who underwent cFF-VMAT at Yokosuka General Hospital Uwamachi, Yokosuka, Japan, from July 2020 to October 2020 were enrolled. Dose-volume histogram (DVH) parameters of the target volume, normal organs, monitor units (MU), and beam-on time (BOT) were compared between cFF-VMAT and FFF-VMAT plans. Results No significant difference was observed for DVH parameters for the target volume. No significant difference was observed in all parameters for the bladder and rectum between the cFF-VMAT and FFF-VMAT groups. The mean values of MU were 686 ± 52 and 784 ± 80 in cFF-VMAT and FFF-VMAT, respectively (p < 0.001). The mean BOT was 97.0 ± 6.6 s and 72.9 ± 1.4 s for cFF-VMAT and FFF-VMAT, respectively (p < 0.001). Conclusion DVH parameters of the target volume and normal organs were not significantly different between the cFF-VMAT and FFF-VMAT plans. In FFF-VMAT, MU was significantly higher, and the BOT was significantly shorter than those in cFF-VMAT.
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Affiliation(s)
- Yosuke Takakusagi
- Department of Radiation Oncology, Kanagawa Cancer Center, Yokohama, JPN
| | - Keisuke Usui
- Department of Radiation Oncology, Juntendo University, Tokyo, JPN
| | | | - Jun Nagatsuka
- Department of Radiology, Yokosuka General Hospital Uwamachi, Yokosuka, JPN
| | - Takeshi Hikage
- Department of Radiology, Yokosuka General Hospital Uwamachi, Yokosuka, JPN
| | - Yasuhiko Kodama
- Department of Radiology, Yokosuka General Hospital Uwamachi, Yokosuka, JPN
| | - Takatomo Ezura
- Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, JPN
| | - Terufumi Kusunoki
- Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, JPN
| | - Yukio Oizumi
- Department of Radiation Oncology, Yokosuka General Hospital Uwamachi, Yokosuka, JPN
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Visak J, Webster A, Bernard ME, Kudrimoti M, Randall ME, McGarry RC, Pokhrel D. Fast generation of lung SBRT plans with a knowledge-based planning model on ring-mounted Halcyon Linac. J Appl Clin Med Phys 2021; 22:54-63. [PMID: 34562308 PMCID: PMC8598154 DOI: 10.1002/acm2.13427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/23/2021] [Accepted: 09/07/2021] [Indexed: 12/31/2022] Open
Abstract
Purpose To demonstrate fast treatment planning feasibility of stereotactic body radiation therapy (SBRT) for centrally located lung tumors on Halcyon Linac via a previously validated knowledge‐based planning (KBP) model to support offline adaptive radiotherapy. Materials/methods Twenty previously treated non‐coplanar volumetric‐modulated arc therapy (VMAT) lung SBRT plans (c‐Truebeam) on SBRT‐dedicated C‐arm Truebeam Linac were selected. Patients received 50 Gy in five fractions. c‐Truebeam plans were re‐optimized for Halcyon manually (m‐Halcyon) and with KBP model (k‐Halcyon). Both m‐Halcyon and k‐Halcyon plans were normalized for identical or better target coverage than clinical c‐Truebeam plans and compared for target conformity, dose heterogeneity, dose fall‐off, and dose tolerances to the organs‐at‐risk (OAR). Treatment delivery parameters and planning times were evaluated. Results k‐Halcyon plans were dosimetrically similar or better than m‐Halcyon and c‐Truebeam plans. k‐Halcyon and m‐Halcyon plan comparisons are presented with respect to c‐Truebeam. Differences in conformity index were statistically insignificant in k‐Halcyon and on average 0.02 higher (p = 0.04) in m‐Halcyon plans. Gradient index was on average 0.43 (p = 0.006) lower and 0.27 (p = 0.02) higher for k‐Halcyon and m‐Halcyon, respectively. Maximal dose 2 cm away in any direction from target was statistically insignificant. k‐Halcyon increased maximal target dose on average by 2.9 Gy (p < 0.001). Mean lung dose was on average reduced by 0.10 Gy (p = 0.004) in k‐Halcyon and increased by 0.14 Gy (p < 0.001) in m‐Halcyon plans. k‐Halcyon plans lowered bronchial tree dose on average by 1.2 Gy. Beam‐on‐time (BOT) was increased by 2.85 and 1.67 min, on average for k‐Halcyon and m‐Halcyon, respectively. k‐Halcyon plans were generated in under 30 min compared to estimated dedicated 180 ± 30 min for m‐Halcyon or c‐Truebeam plan. Conclusion k‐Halcyon plans were generated in under 30 min with excellent plan quality. This adaptable KBP model supports high‐volume clinics in the expansion or transfer of lung SBRT patients to Halcyon.
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Affiliation(s)
- Justin Visak
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Aaron Webster
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Mahesh Kudrimoti
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Marcus E Randall
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Ronald C McGarry
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
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Dosimetric impact of FFF over FF beam using VMAT for brain neoplasms treated with radiotherapy. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2021. [DOI: 10.2478/pjmpe-2021-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Background: This study was conducted to assess the dosimetric impact of FFF beam plans on high-grade brain neoplasms using the VMAT technique when compared with FF beam plans.
Material and Methods: Thirty patients with high-grade brain neoplasms, who had received radiotherapy using VMAT technique retrospectively were selected for this study. All the patients were planned for VMAT using 6MV_FF beam and the same plan was re-optimized using 6MV_FFF beam keeping the same dose constraint. Radiotherapy dose distribution on planning target volume (PTV) and organs at risk (OAR), target conformity index (CI), Homogeneity Index (HI), Low dose volume in the patient (V5, V10, V20, and V30), and Integral dose to the whole body in both plans were compared.
Results: The PTV coverage and OAR’s showed no significant differences in dose distribution between the FFF and FF beam VMAT planning. There was a reduction of the average maximum dose in the right eye, left eye, right optic nerve, and left optic nerve using FFF beams. The reduction in average low dose volume was observed in V5, V10, V20, V30, and Mean Dose. Also, a significant reduction was observed in the integral dose to the whole body using the FFF beam.
Conclusions: Using FFF beams with VMAT is doable for the treatment of high-grade brain neoplasms, and the delivery mode of the FFF beam in VMAT may yield similar results to FF beam which should be confirmed in a large scale prospective clinical trial.
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Kaliyaperumal V, Abraham S, Veni M, Banerjee S, Tamilselvan S, Gupta D, Dayanithi K, Manigandan D, Mishra S, Bisht SS, Kataria T. Dosimetric Comparison of Robotic and Linear Accelerator Multi-Leaf Collimator-Based Stereotactic Radiosurgery for Arteriovenous Malformation. J Med Phys 2021; 46:16-25. [PMID: 34267485 PMCID: PMC8240906 DOI: 10.4103/jmp.jmp_79_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose: To investigate the dosimetric comparison of different collimators which are used in robotic radiosurgery (cyberknife-CK) and linear accelerator (LINAC) for stereotactic radiosurgery (SRS) in arteriovenous malformation (AVM). Materials and Methods: Twenty-five AVM patients were planned in CK using FIXED cone, IRIS collimator, and multi-leaf collimator (MLC) based in LINAC. Dosimetric comparison was performed using Paddick conformity index (CIPaddick) and International Commission on Radiation Units and measurements (ICRU) homogeneity index (HIICRU), gradient score (GS), normal brain dose received by 10cc (D10cc) and critical structure (brain stem, optic chiasma, optic nerves) doses. Paired sample t-test was used for statistical analysis. Results: Mean treatment volume was 3.16cc (standard deviation ± 4.91cc). No significant deviation (P =0.45, 0.237 for FIXED vs. IRIS and FIXED vs. MLC, respectively) was found in target coverage. For CIPaddick, the mean difference (MD) between FIXED- and MLC-based plans was 0.16(P = 0.001); For HIICRU, difference between FIXED and IRIS was insignificant (0.5, P = 0.823); but, when FIXED versus MLC, the deviation was 7.99% (P = 0.002). In FIXED- and MLC-based plans, significant difference was found in GS70 and GS40 (P < 0.041 and 0.005, respectively). MD between FIXED- and MLC-based plans for normal brain for 5Gy, 10Gy, 12Gy, and 20Gy were 36.08cc (P = 0.009), 7.12cc (P = 0.000), 5.84cc (P = 0.000) and 1.56cc (P = 0.000), respectively. AVM volume <0.7cc should be treated with CK FIXED and >0.7cc were treated by using FIXED or IRIS collimators. AVM volume > 1.4cc can be treated by either LINAC MLC-based SRS or CK. Conclusion: Our study shows CK collimator (IRIS and FIXED) could be able to treat brain AVMs in any size. Linac MLC-based SRS has some limitations in terms of conformity and low-dose spillage, and advantages like reduced treatment time and MU.
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Affiliation(s)
- Venkatesan Kaliyaperumal
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Susan Abraham
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Maragatha Veni
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Susovan Banerjee
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - S Tamilselvan
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Deepak Gupta
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - K Dayanithi
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - D Manigandan
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Saumyaranjan Mishra
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Shyam Singh Bisht
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
| | - Tejinder Kataria
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India
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Kodama T, Yasui K, Nishioka S, Miyaura K, Takakura T, Katayose T, Nakamura M. Survey on utilization of flattening filter-free photon beams in Japan. JOURNAL OF RADIATION RESEARCH 2021; 62:726-734. [PMID: 34036361 PMCID: PMC8273795 DOI: 10.1093/jrr/rrab042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/08/2021] [Indexed: 06/12/2023]
Abstract
To understand the current state of flattening filter-free (FFF) beam implementation in C-arm linear accelerators (LINAC) in Japan, the quality assurance (QA)/quality control (QC) 2018-2019 Committee of the Japan Society of Medical Physics (JSMP) conducted a 37-question survey, designed to investigate facility information and specifications regarding FFF beam adoption and usage. The survey comprised six sections: facility information, devices, clinical usage, standard calibration protocols, modeling for treatment planning (TPS) systems and commissioning and QA/QC. A web-based questionnaire was developed. Responses were collected between 18 June and 18 September 2019. Of the 846 institutions implementing external radiotherapy, 323 replied. Of these institutions, 92 had adopted FFF beams and 66 had treated patients using them. FFF beams were used in stereotactic radiation therapy (SRT) for almost all disease sites, especially for the lungs using 6 MV and liver using 10 MV in 51 and 32 institutions, respectively. The number of institutions using FFF beams for treatment increased yearly, from eight before 2015 to 60 in 2018. Farmer-type ionization chambers were used as the standard calibration protocol in 66 (72%) institutions. In 73 (80%) institutions, the beam-quality conversion factor for FFF beams was calculated from TPR20,10, via the same protocol used for beams with flattening filter (WFF). Commissioning, periodic QA and patient-specific QA for FFF beams also followed the procedures used for WFF beams. FFF beams were primarily used in high-volume centers for SRT. In most institutions, measurement and QA was conducted via the procedures used for WFF beams.
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Affiliation(s)
- Takumi Kodama
- Department of Radiation Oncology, Saitama Cancer Center, 780 Ooazakomuro, Inamachi, Kitaadachi-gun, Saitama 362-0806, Japan
| | - Keisuke Yasui
- Faculty of Radiological Technology, School of Health Science, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470–1192, Japan
| | - Shie Nishioka
- Department of Medical Physics, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104–0045, Japan
| | - Kazunori Miyaura
- Graduate School of Health Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142–8666, Japan
| | - Toru Takakura
- Department of Radiation Therapy, Uji-Tokushukai Medical Center, 145 Ishibashi, Makichima-cho, Uji-shi, Kyoto 611–0041, Japan
| | - Tetsurou Katayose
- Department of Radiation Oncology, Chiba Cancer Center, 666-2 Nitona-cho, Chuo-ku, Chiba 260–8717, Japan
| | - Mitsuhiro Nakamura
- Department of Information Technology and Medical engineering, Human Health Science, Graduate School of Medicine, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
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Critchfield LS, Bernard ME, Randall ME, McGarry RC, Pokhrel D. A novel restricted single-isocenter stereotactic body radiotherapy (RESIST) method for synchronous multiple lung lesions to minimize setup uncertainties. Med Dosim 2021; 46:419-425. [PMID: 34148728 DOI: 10.1016/j.meddos.2021.05.005] [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: 11/13/2020] [Revised: 04/01/2021] [Accepted: 05/18/2021] [Indexed: 10/21/2022]
Abstract
Treating multiple lung lesions synchronously using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can improve treatment efficiency and patient compliance. However, due to set up uncertainty, aligning multiple lung tumors on a single daily cone beam CT (CBCT) image has shown clinically unacceptable loss of target(s) coverage. Herein, we propose a Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST), an alternative treatment that mitigates patient setup uncertainties. Twenty-one patients with two lung lesions were treated with single-isocenter VMAT-SBRT using a 6MV-FFF beam to 54 Gy in 3 fractions (n = 7) or 50 Gy in 5 fractions (n = 14) prescribed to 70-80% isodose line. To minimize setup uncertainties, each plan was re-planned using the RESIST method, utilizing a single-isocenter placed at the patient's mediastinum. It allows for an individual plan to be created for each tumor, using the first plan as the base-dose for the second plan, while still allowing both tumors to be treated in the same session. The technique uses novel features in Eclipse, including dynamic conformal arc (DCA)-based dose and aperture shape controller before each VMAT optimization. RESIST plans provided better target dose conformity (p < 0.001) and gradient indices (p < 0.001) and lower dose to adjacent critical organs. Using RESIST to treat synchronous lung lesions with VMAT-SBRT significantly reduces plan complexity as demonstrated by smaller beam modulation factors (p < 0.001), without unreasonably increasing treatment time. RESIST reduces the chance of a geometric miss due by allowing CBCT matching of one tumor at a time. Placement of isocenter at the mediastinum avoids potential patient/gantry collisions, provides greater flexibility of noncoplanar arcs and eliminates the need for multiple couch movements during CBCT imaging. Efficacy of RESIST has been demonstrated for two lesions and can potentially be used for more lesions. Clinical implementation of this technique is ongoing.
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Affiliation(s)
- Lana Sanford Critchfield
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Marcus E Randall
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Ronald C McGarry
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
| | - Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Oncology, University of Kentucky, Lexington KY, USA
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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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Out-of-field dose in stereotactic radiotherapy for paediatric patients. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 19:1-5. [PMID: 34307913 PMCID: PMC8295843 DOI: 10.1016/j.phro.2021.05.006] [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: 12/22/2020] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 11/23/2022]
Abstract
Background and purpose Stereotactic radiotherapy combines image guidance and high precision delivery with small fields to deliver high doses per fraction in short treatment courses. In preparation for extension of these treatment techniques to paediatric patients we characterised and compared doses out-of-field in a paediatric anthropomorphic phantom for small flattened and flattening filter free (FFF) photon beams. Method and materials Dose measurements were taken in several organs and structures outside the primary field in an anthropomorphic phantom of a 5 year old child (CIRS) using thermoluminescence dosimetry (LiF:Mg,Cu,P). Out-of-field doses from a medical linear accelerator were assessed for 6 MV flattened and FFF beams of field sizes between 2 × 2 and 10 × 10 cm2. Results FFF beams resulted in reduced out-of-field doses for all field sizes when compared to flattened beams. Doses for FFF and flattened beams converged for all field sizes at larger distances (>40 cm) from the central axis as leakage becomes the primary source of out-of-field dose. Rotating the collimator to place the MLC bank in the longitudinal axis of the patient was shown to reduce the peripheral doses measured by up to 50% in Varian linear accelerators. Conclusion Minimising out-of-field doses by using FFF beams and aligning the couch and collimator to provide tertiary shielding demonstrated advantages of small field, FFF treatments in a paediatric setting.
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Pokhrel D, Visak J. Letter to the Editor: In Response to Sarkar et al. J Appl Clin Med Phys 2021; 22:283-285. [PMID: 34043270 PMCID: PMC8200499 DOI: 10.1002/acm2.13277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/22/2022] Open
Affiliation(s)
- Damodar Pokhrel
- Department of Radiation Medicine, Medical Physics Graduate program, University of Kentucky, Lexington, KY, USA
| | - Justin Visak
- Department of Radiation Medicine, Medical Physics Graduate program, University of Kentucky, Lexington, KY, USA
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Hanley J, Dresser S, Simon W, Flynn R, Klein EE, Letourneau D, Liu C, Yin FF, Arjomandy B, Ma L, Aguirre F, Jones J, Bayouth J, Holmes T. AAPM Task Group 198 Report: An implementation guide for TG 142 quality assurance of medical accelerators. Med Phys 2021; 48:e830-e885. [PMID: 34036590 DOI: 10.1002/mp.14992] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/16/2021] [Accepted: 04/28/2021] [Indexed: 11/11/2022] Open
Abstract
The charges on this task group (TG) were as follows: (a) provide specific procedural guidelines for performing the tests recommended in TG 142; (b) provide estimate of the range of time, appropriate personnel, and qualifications necessary to complete the tests in TG 142; and (c) provide sample daily, weekly, monthly, or annual quality assurance (QA) forms. Many of the guidelines in this report are drawn from the literature and are included in the references. When literature was not available, specific test methods reflect the experiences of the TG members (e.g., a test method for door interlock is self-evident with no literature necessary). In other cases, the technology is so new that no literature for test methods was available. Given broad clinical adaptation of volumetric modulated arc therapy (VMAT), which is not a specific topic of TG 142, several tests and criteria specific to VMAT were added.
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Affiliation(s)
- Joseph Hanley
- Princeton Radiation Oncology, Monroe, New Jersey, 08831, USA
| | - Sean Dresser
- Winship Cancer Institute, Radiation Oncology, Emory University, Atlanta, Georgia, 30322, USA
| | | | - Ryan Flynn
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Eric E Klein
- Brown university, Rhode Island Hospital, Providence, Rhode Island, 02905, USA
| | | | - Chihray Liu
- University of Florida, Gainesville, Florida, 32610-0385, USA
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Bijan Arjomandy
- Karmanos Cancer Institute at McLaren-Flint, Flint, Michigan, 48532, USA
| | - Lijun Ma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, 94143-0226, USA
| | | | - Jimmy Jones
- Department of Radiation Oncology, The University of Colorado Health-Poudre Valley, Fort Collins, Colorado, 80525, USA
| | - John Bayouth
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, 53792-0600, USA
| | - Todd Holmes
- Varian Medical Systems, Palo Alto, California, 94304, USA
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Tattenberg S, Hyde D, Milette MP, Parodi K, Araujo C, Carlone M. Assessment of the Sun Nuclear ArcCHECK to detect errors in 6MV FFF VMAT delivery of brain SABR using ROC analysis. J Appl Clin Med Phys 2021; 22:35-44. [PMID: 34021691 PMCID: PMC8200516 DOI: 10.1002/acm2.13276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/24/2021] [Accepted: 04/19/2021] [Indexed: 11/11/2022] Open
Abstract
Institutions use a range of different detector systems for patient-specific quality assurance (QA) measurements conducted to assure that the dose delivered by a patient's radiotherapy treatment plan matches the calculated dose distribution. However, the ability of different detectors to detect errors from different sources is often unreported. This study contains a systematic evaluation of Sun Nuclear's ArcCHECK in terms of the detectability of potential machine-related treatment errors. The five investigated sources of error were multileaf collimator (MLC) leaf positions, gantry angle, collimator angle, jaw positions, and dose output. The study encompassed the clinical treatment plans of 29 brain cancer patients who received stereotactic ablative radiotherapy (SABR). Six error magnitudes were investigated per source of error. In addition, the Eclipse AAA beam model dosimetric leaf gap (DLG) parameter was varied with four error magnitudes. Error detectability was determined based on the area under the receiver operating characteristic (ROC) curve (AUC). Detectability of DLG errors was good or excellent (AUC >0.8) at an error magnitude of at least ±0.4 mm, while MLC leaf position and gantry angle errors reached good or excellent detectability at error magnitudes of at least 1.0 mm and 0.6°, respectively. Ideal thresholds, that is, gamma passing rates, to maximize sensitivity and specificity ranged from 79.1% to 98.7%. The detectability of collimator angle, jaw position, and dose output errors was poor for all investigated error magnitudes, with an AUC between 0.5 and 0.6. The ArcCHECK device's ability to detect errors from treatment machine-related sources was evaluated, and ideal gamma passing rate thresholds were determined for each source of error. The ArcCHECK was able to detect errors in DLG value, MLC leaf positions, and gantry angle. The ArcCHECK was unable to detect the studied errors in collimator angle, jaw positions, and dose output.
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Affiliation(s)
- Sebastian Tattenberg
- Department of Medical Physics, Ludwig Maximilian University of Munich, Garching, Germany.,Irving K. Barber Faculty of Science, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada
| | - Derek Hyde
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada.,Centre for the Southern Interior, Department of Medical Physics, BC Cancer Agency, Kelowna, BC, Canada
| | - Marie-Pierre Milette
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada.,Centre for the Southern Interior, Department of Medical Physics, BC Cancer Agency, Kelowna, BC, Canada
| | - Katia Parodi
- Department of Medical Physics, Ludwig Maximilian University of Munich, Garching, Germany
| | - Cynthia Araujo
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada.,Centre for the Southern Interior, Department of Medical Physics, BC Cancer Agency, Kelowna, BC, Canada
| | - Marco Carlone
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada.,Centre for the Southern Interior, Department of Medical Physics, BC Cancer Agency, Kelowna, BC, Canada
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Chofor N, Bopda P, Bücker R, Ivo A, Okonkwo E, Joel K, Tung Z, Ige T, Wirtz H, Ngwa W. Mobilising stakeholders to improve access to state-of-the-art radiotherapy in low- and middle-income countries. Ecancermedicalscience 2021; 15:1227. [PMID: 34158831 PMCID: PMC8183652 DOI: 10.3332/ecancer.2021.1227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Indexed: 12/24/2022] Open
Abstract
In an ongoing effort to improve access to state-of-the-art radiotherapy in low- and middle-income countries (LMICs), a joint symposium was organised by the non-governmental, non-profit organisation Medical physicists in diaspora for Africa e.V. (MephidA e.V.) in collaboration with the Germany-based Cameroon-German medical doctor’s association (Camfomedics e.V.) and the Harvard-based Global Health Catalyst summit. The goal of the symposium was to discuss the technical and structural challenges faced in African LMIC settings, re-evaluate strategies to overcome the shortfall of radiotherapy services and ameliorate the situation. The meeting brought together industry partners, including radiotherapy machine vendors and dosimetry solution providers, alongside public health, oncology and medical physics experts. This paper summarises the deliberations and recommendations based on the ongoing efforts including the use of information and communication technologies towards the provision of expert knowledge and telemedicine, the use of solar energy to avoid power outages and the use of high-end technology for enhanced quality assurance. We also present the experiences on the first linac installation at the Rwanda Military Hospital, the challenges faced in this LMIC as well as the patient’s demography, reflecting the reality in most sub-Saharan LMICs.
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Affiliation(s)
| | - Pierre Bopda
- Strahlentherapie Agaplesion Diakonieklinikum Rotenburg, Elise-Averdieck-Str. 17, 27356 Rotenburg, Germany
| | - Rebecca Bücker
- Strahlentherapie Klinikum Lippe GmbH, Rintelner Straße 85, 32657 Lemgo, Germany
| | - Azeh Ivo
- Onkologische Praxis und Tagesklinik, Ahstr. 2, 45879 Gelsenkirchen, Germany
| | - Ernest Okonkwo
- Strahlentherapie Ortenau Klinikum, Weingartenstr. 70, 77654 Offenburg, Germany
| | - Kra Joel
- Radiotherapy Department, Military Hospital, PO Box 3377, Kigali, Rwanda
| | - Zanzem Tung
- Zentrum für Strahlentherapie und Radioonkologie, Mozartstraße 30, 26655 Westerstede, Germany
| | - Taofeeq Ige
- Medical Physics Department, National Hospital Abuja, Abuja, FCT 900001, Nigeria.,University of Abuja, Abuja, Nigeria
| | - Holger Wirtz
- Strahlentherapie Singen-Friedrichshafen, Virchowstraße 10b D-78224 Singen/Hohentwiel, Germany
| | - Wilfred Ngwa
- Harvard Medical School, Brigham and Women's Hospital, Dana Farber Cancer Institute, Boston, MA 02115, USA.,University of Massachusetts Lowell, Boston, MA 02115, USA
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Hermida-López M, Sánchez-Artuñedo D, Rodríguez M, Brualla L. Monte Carlo simulation of conical collimators for stereotactic radiosurgery with a 6 MV flattening-filter-free photon beam. Med Phys 2021; 48:3160-3171. [PMID: 33715167 DOI: 10.1002/mp.14837] [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: 11/15/2020] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Conical collimators, or cones, are tertiary collimators that attach to a radiotherapy linac and are suited for the stereotactic radiosurgery treatment of small brain lesions. The small diameter of the most used cones makes difficult the acquisition of the dosimetry data needed for the commissioning of treatment planning systems. Although many publications report dosimetric data of conical collimators for stereotactic radiosurgery, most of the works use different setups, which complicates comparisons. In other cases, the cone output factors reported do not take into account the effect of the small cone diameter on the detector response. Finally, few data exist on the dosimetry of cones with flattening-filter-free (FFF) beams from modern linac models. This work aims at obtaining a dosimetric characterization of the conical collimators manufactured by Brainlab AG (Munich, Germany) in a 6 MV FFF beam from a TrueBeam STx linac (Varian Medical Systems). METHODS Percentage depth dose curves, lateral dose profiles and cone output factors were obtained using Monte Carlo simulations for the cones with diameters of 4, 5, 6, 7.5, 8, 10, 12.5, 15, 17.5, 20, 25, and 30 mm. The simulation of the linac head was carried out with the PRIMO Monte Carlo software, and the simulations of the cones and the water phantom were run with the general-purpose Monte Carlo code PENELOPE. The Monte Carlo model was validated by comparing the simulation results with measurements performed for the cones of 4, 5, and 7.5 mm of diameter using a stereotactic field diode, a microDiamond detector and EBT3 radiochromic film. In addition, for those cones, simulations and measurements were done for comparison purposes, by reproducing the experimental setups from the available publications. RESULTS The experimental data acquired for the cones of 4, 5, and 7.5 mm validated the developed Monte Carlo model. The simulations accurately reproduced the experimental depths of maximum dose and the dose ratio at 20- and 10-cm depth (PDD20/10 ). A good agreement was obtained between simulated and experimental lateral dose profiles: The differences in the full-width at half-maximum were smaller than 0.2 mm, and the differences in the penumbra 80%-20% were smaller than 0.25 mm. The difference between the simulated and the average of the experimental output factors for the cones of 4, 5, and 7.5 mm of diameter was 0.0%, 0.0%, and 3.0%, respectively, well within the statistical uncertainty of the simulations (4.4% with coverage factor k = 2). It was also found that the simulated cone output factors agreed within 2% with the average of output factors reported in the literature for a variety of setup conditions, detectors, beam qualities, and cone manufacturers. CONCLUSION A Monte Carlo model of cones for stereotactic radiosurgery has been developed and validated. The cone dosimetry dataset obtained in this work, consisting of percentage depth doses, lateral dose profiles and output factors, is useful to benchmark data acquired for the commissioning of cone-based radiosurgery treatment planning systems.
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Affiliation(s)
- Marcelino Hermida-López
- Servei de Física i Protecció Radiològica, Hospital Universitari Vall d'Hebron, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain
| | - David Sánchez-Artuñedo
- Servei de Física i Protecció Radiològica, Hospital Universitari Vall d'Hebron, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain
| | - Miguel Rodríguez
- Centro Médico Paitilla, Calle 53 y ave. Balboa, Panama City, Panama.,Instituto de Investigaciones Científicas y de Alta Tecnología, INDICASAT-AIP, City of Knowledge, Building 219, Panama City, Panama
| | - Lorenzo Brualla
- West German Proton Therapy Centre Essen (WPE), Hufelandstr. 55, Essen, 45147, Germany.,West German Cancer Centre (WTZ), Hufelandstr. 55, Essen, 45147, Germany.,Faculty of Medicine, University of Duisburg-Essen, Hufelandstr. 55, Essen, 45147, Germany
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Lorenz FH, Paris MI. Identification of a potential source of error for 6FFF beams delivered on an Agility TM multileaf collimator. J Appl Clin Med Phys 2021; 22:92-98. [PMID: 33675145 PMCID: PMC8035561 DOI: 10.1002/acm2.13212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 01/02/2021] [Accepted: 01/02/2021] [Indexed: 11/07/2022] Open
Abstract
Purpose The performance of the AgilityTM multileaf collimator was investigated with a focus on dynamic, small fields for flattening filter free (FFF) beams. Methods In this study we have developed a simple tool to test the robustness of the control mechanisms during dynamic beam delivery for Elekta’s VersaHD linear accelerator with Integrity 4.0.4 control software. We have programed the planning system to calculate dose for delivery of sweeping gaps. These sweeping gaps have a constant speed, constant size, and are delivered at a constant dose rate. Therefore they specifically identify delivery problems in dynamic mode. Results The Elekta AgilityTM control mechanism fails to maintain accurate delivery for small, dynamic sweeping gaps. For small gap sizes, the AgilityTM control mechanism delivers a field that is more than four times the size of the planned field width without generating an interlock. This has dosimetric implications: The discrepancy between calculated and measured doses increases with decreasing gap size and exceeds 10% and 60% at isocenter for a 3.5 mm and 1 mm gap size, respectively. Conclusion A deficiency of the AgilityTM control system was identified in this study. This deficiency is a potential source of error for volumetric modulated arc therapy fields and could therefore contribute to relatively high failure rates in quality assurance measurements, especially for FFF beams.
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Affiliation(s)
- Friedlieb H. Lorenz
- Department of Radiation OncologySouthern District Health BoardDunedinNew Zealand
| | - Matthew I. Paris
- Department of Radiation OncologySouthern District Health BoardDunedinNew Zealand
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Martin-Martin G, Walter S, Guibelalde E. Dose accuracy improvement on head and neck VMAT treatments by using the Acuros algorithm and accurate FFF beam calibration. ACTA ACUST UNITED AC 2021; 26:73-85. [PMID: 33948305 DOI: 10.5603/rpor.a2021.0014] [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: 09/18/2020] [Accepted: 12/22/2020] [Indexed: 11/25/2022]
Abstract
Background The purpose of this study was to assess dose accuracy improvement and dosimetric impact of switching from the anisotropic analytical algorithm (AA) to the Acuros XB algorithm (AXB) when performing an accurate beam calibration in head and neck (H&N) FFF-VMAT treatments. Materials and methods Twenty H&N cancer patients treated with FFF-VMAT techniques were included. Calculations were performed with the AA and AXB algorithm (dose-to-water - AXBw- and dose-to-medium - AXBm-). An accurate beam calibration was used for AXB calculations. Dose prescription to the tumour (PTV70) and at-risk-nodal region (PTV58.1) were 70 Gy and 58.1 Gy, respectively. A PTV70_bone including bony structures in PTV70 was contoured. Dose-volume parameters were compared between the algorithms. Statistical tests were used to analyze the differences in mean values and the correlation between compliance with the D95 > 95% requirement and occurrence of local recurrence. Results AA systematically overestimated the dose compared to AXB algorithm with mean dose differences within 1.3 Gy/2%, except for the PTV70_bone (2.2 Gy/3.2%). Dose differences were significantly higher for AXBm calculations when including accurate beam calibration (maximum dose differences up to 2.8 Gy/4.1% and 4.2 Gy/6.3% for PTV70 and PTV70_bone, respectively). 80% of AA-calculated plans did not meet the D95 > 95% requirement after recalculation with AXBm and accurate beam calibration. The reduction in D95 coverage in the tumour was not clinically relevant. Conclusions Using the AXBm algorithm and carefully reviewing the beam calibration procedure in H&N FFF-VMAT treatments ensures (1) dose accuracy increase by approximately 3%; (2) a consequent dose increase in targets; and (3) a dose reporting mode that is consistent with the trend of current algorithms.
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Affiliation(s)
- Guadalupe Martin-Martin
- Medical Physics and Radiation Protection Service, Hospital Universitario de Fuenlabrada, Madrid, Spain
| | - Stefan Walter
- Department of Medicine and Public Health, Rey Juan Carlos University, Alcorcón, Spain
| | - Eduardo Guibelalde
- Medical Physics Group, Department of Radiology, University Complutense of Madrid, Madrid, Spain
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Sun T, Lin X, Zhang G, Qiu Q, Li C, Yin Y. Treatment planning comparison of volumetric modulated arc therapy with the trilogy and the Halcyon for bilateral breast cancer. Radiat Oncol 2021; 16:35. [PMID: 33602267 PMCID: PMC7890882 DOI: 10.1186/s13014-021-01763-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/11/2021] [Indexed: 12/12/2022] Open
Abstract
Background The Halcyon is a new machine from the Varian company. The purpose of this study was to evaluate the dosimetry of the Halcyon in treatment of bilateral breast cancer with volumetric modulated arc therapy. Methods On CT images of 10 patients with bilateral breast cancer, four Halcyon plans with different setup fields were generated, and dosimetric comparisons using Bonferroni’s multiple comparisons test were conducted among the four plans. Whole and partial arc plans on the Trilogy and the Halcyon, referred to as T-4arc, T-8arc, H-4arc and H-8arc, were designed. The prescription dose was 50 Gy in 2-Gy fractions. All plans were designed with the Eclipse version 15.5 treatment planning system. The dosimetric differences between whole and partial arc plans in the same accelerator were compared using the Mann–Whitney U test. The better Halcyon plan was selected for the further dosimetric comparison of the plan quality and delivery efficiency between the Trilogy and the Halcyon. Results Halcyon plans with high‐quality megavoltage cone beam CT setup fields increased the Dmean, D2 and V107 of the planning target volume (PTV) and the V5 and Dmean of the heart, left ventricle (LV) and lungs compared with other Halcyon setup plans. The mean dose and low dose volume of the heart, lungs and liver were significantly decreased in T-8arc plans compared to T-4arc plans. In terms of the V5, V20, V30, V40 and Dmean of the heart, the V20, V30, V40 and Dmean of the LV, the V30, V40, Dmax and Dmean of the left anterior descending artery (LAD), and the V5 and V40 of lungs, H-8arc was significantly higher than H-4arc (p < 0.05). Compared with the Trilogy’s plans, the Halcyon’s plans reduced the high-dose volume of the heart and LV but increased the mean dose of the heart. For the dose of the LAD and the V20 and V30 of lungs, there was no significant difference between the two accelerators. Compared with the Trilogy, plans on the Halcyon significantly increased the skin dose but also significantly reduced the delivery time. Conclusion For the Halcyon, the whole-arc plans have more dosimetric advantages than partial-arc plans in bilateral breast cancer radiotherapy. Although the mean dose of the heart and the skin dose are increased, the doses of the cardiac substructure and other OARs are comparable to the Trilogy, and the delivery time is significantly reduced.
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Affiliation(s)
- Tao Sun
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China
| | - Xiutong Lin
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China
| | - Guifang Zhang
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China
| | - Qingtao Qiu
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China
| | - Chengqiang Li
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China
| | - Yong Yin
- Department of Radiation Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, 440 Jiyan Road, Jinan, 250117, Shandong, China.
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Lam S, Bradley D, Khandaker M. Small-field radiotherapy photon beam output evaluation: Detectors reviewed. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.108950] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Pokhrel D, Visak J, Critchfield LC, Stephen J, Bernard ME, Randall M, Kudrimoti M. Clinical validation of ring-mounted halcyon linac for lung SBRT: comparison to SBRT-dedicated C-arm linac treatments. J Appl Clin Med Phys 2020; 22:261-270. [PMID: 33342070 PMCID: PMC7856490 DOI: 10.1002/acm2.13146] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/19/2020] [Accepted: 12/04/2020] [Indexed: 12/31/2022] Open
Abstract
Stereotactic body radiotherapy (SBRT) of lung tumors via the ring‐mounted Halcyon Linac, a fast kilovoltage cone beam CT‐guided treatment with coplanar geometry, a single energy 6MV flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a fast, safe, and feasible treatment modality for selected lung cancer patients. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB algorithm with heterogeneity corrections using an SBRT board and Halcyon couch insert. Halcyon VMAT‐SBRT plans with stacked and staggered multileaf collimators produced highly conformal radiosurgical dose distribution to the target, lower intermediate dose spillage, and similar dose to adjacent organs at risks (OARs) compared to SBRT‐dedicated highly conformal clinical noncoplanar Truebeam VMAT plans following the RTOG‐0813 requirements. Due to low monitor units per fraction and less multileaf collimator (MLC) modulation, the Halcyon VMAT plan can deliver lung SBRT fractions with an overall treatment time of less than 15 min (for 50 Gy in five fractions), significantly improving patient comfort and clinic workflow. Higher pass rates of quality assurance results demonstrate a more accurate treatment delivery on Halcyon. We have implemented Halcyon for lung SBRT treatment in our clinic. We suggest others use Halcyon for lung SBRT treatments using abdominal compression or 4D CT‐based treatment planning, thus expanding the access of curative ultra‐hypofractionated treatments to other centers with only a Halcyon Linac. Clinical follow‐up results for patients treated on Halcyon Linac with lung SBRT is ongoing.
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Affiliation(s)
- Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Justin Visak
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Lana C Critchfield
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Joseph Stephen
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Marcus Randall
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Mahesh Kudrimoti
- Medical Physics Graduate Program, Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
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Critchfield LC, Bernard ME, Randall ME, McGarry RC, Pokhrel D. Risk of target coverage loss for stereotactic body radiotherapy treatment of synchronous lung lesions via single-isocenter volumetric modulated arc therapy. J Appl Clin Med Phys 2020; 22:251-260. [PMID: 33342042 PMCID: PMC7856510 DOI: 10.1002/acm2.13145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/21/2020] [Accepted: 12/07/2020] [Indexed: 12/31/2022] Open
Abstract
Treating multiple lung lesions synchronously via single‐isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) improves treatment efficiency and patient compliance. However, aligning multiple lung tumors accurately on single pretreatment cone beam CTs (CBCTs) can be problematic. Tumors misaligned could lead to target coverage loss. To quantify this potential target coverage loss due to small, clinically realistic setup errors, a novel simulation method was developed. This method was used on 26 previously treated patients with two metastatic lung lesions. Patients were treated with 4D CT‐based, highly conformal noncoplanar VMAT plans (clinical VMAT) with 6MV‐flattening filter free (FFF) beam using AcurosXB dose calculation algorithm with heterogeneity corrections. A single isocenter was placed approximately between the lesions to improve patient convenience and clinic workflow. Average isocenter to tumor distance was 5.9 cm. Prescription dose was 54 Gy/50 Gy in 3/5 fractions. For comparison, a plan summation (simulated VMAT) was executed utilizing randomly simulated, clinically relevant setup errors, obtained from pretreatment setup, per treatment fraction, in Eclipse treatment planning system for each of the six degrees of freedom within ± 5.0 mm and ± 2°. Simulations yielded average deviations of 27.4% (up to 72% loss) (P < 0.001) from planned target coverage when treating multiple lung lesions using a single‐isocenter plan. The largest deviations from planned coverage and desired biological effective dose (BED10, with α/β = 10 Gy) were seen for the smallest targets (<10 cc), some of which received < 100 Gy BED10. Patient misalignment resulted in substantial decrease in conformity and increase in the gradient index, violating major characteristics of SBRT. Statistically insignificant differences were seen for normal tissue dose. Although, clinical follow‐up of these patients is ongoing, the authors recommend an alternative treatment planning strategy to minimize the probability of a geometric miss when treating small lung lesions synchronously with single‐isocenter VMAT SBRT plans.
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Affiliation(s)
- Lana C Critchfield
- Medical Physics Graduate Program, Department of Radiation Medicine, University Kentucky, Lexington, KY, USA
| | - Mark E Bernard
- Medical Physics Graduate Program, Department of Radiation Medicine, University Kentucky, Lexington, KY, USA
| | - Marcus E Randall
- Medical Physics Graduate Program, Department of Radiation Medicine, University Kentucky, Lexington, KY, USA
| | - Ronald C McGarry
- Medical Physics Graduate Program, Department of Radiation Medicine, University Kentucky, Lexington, KY, USA
| | - Damodar Pokhrel
- Medical Physics Graduate Program, Department of Radiation Medicine, University Kentucky, Lexington, KY, USA
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