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Spenkelink GB, Huijskens SC, Zindler JD, de Goede M, van der Star WJ, van Egmond J, Petoukhova AL. Comparative assessment and QA measurement array validation of Monte Carlo and Collapsed Cone dose algorithms for small fields and clinical treatment plans. J Appl Clin Med Phys 2024:e14522. [PMID: 39287551 DOI: 10.1002/acm2.14522] [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: 05/09/2024] [Revised: 07/12/2024] [Accepted: 08/06/2024] [Indexed: 09/19/2024] Open
Abstract
PURPOSE Many studies have demonstrated superior performance of Monte Carlo (MC) over type B algorithms in heterogeneous structures. However, even in homogeneous media, MC dose simulations should outperform type B algorithms in situations of electronic disequilibrium, such as small and highly modulated fields. Our study compares MC and Collapsed Cone (CC) dose algorithms in RayStation 12A. Under consideration are 6 MV and 6 MV flattening filter-free (FFF) photon beams, relevant for VMAT plans such as head-and-neck and stereotactic lung treatments with heterogeneities, as well as plans for multiple brain metastases in one isocenter, involving highly modulated small fields. We aim to investigate collimator angle dependence of small fields and performance differences between different combinations of ArcCHECK configuration and dose algorithm. METHODS Several verification tests were performed, ranging from simple rectangular fields to highly modulated clinical plans. To evaluate and compare the performance of the models, the agreements between calculation and measurement are compared between MC and CC. Measurements include water tank measurements for test fields, ArcCHECK measurements for test fields and VMAT plans, and film dosimetry for small fields. RESULTS AND CONCLUSIONS In very small or narrow fields, our measurements reveal a strong dependency of dose output to collimator angle for VersaHD with Agility MLC, reproduced by both dose algorithms. ArcCHECK results highlight a suboptimal agreement between measurements and MC calculations for simple rectangular fields when using inhomogeneous ArcCHECK images. Therefore, we advocate for the use of homogeneous phantom images, particularly for static fields, in ArcCHECK verification with MC. MC might offer performance benefits for more modulated treatment fields. In ArcCHECK results for clinical plans, MC performed comparable to CC for 6 MV. For 6 MV FFF and the preferred homogeneous phantom image, MC resulted in consistently better results (13%-64% lower mean gamma index) compared to CC.
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Affiliation(s)
- Guus B Spenkelink
- Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands
| | - Sophie C Huijskens
- Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands
| | - Jaap D Zindler
- Haaglanden Medical Center, Department of Radiation Oncology, Leidschendam, The Netherlands
- HollandPTC, Department of Radiotherapy, Delft, The Netherlands
| | - Marc de Goede
- Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands
| | | | - Jaap van Egmond
- Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands
| | - Anna L Petoukhova
- Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands
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Khaledi N, Khan R, Gräfe JL. Historical Progress of Stereotactic Radiation Surgery. J Med Phys 2023; 48:312-327. [PMID: 38223793 PMCID: PMC10783188 DOI: 10.4103/jmp.jmp_62_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 01/16/2024] Open
Abstract
Radiosurgery and stereotactic radiotherapy have established themselves as precise and accurate areas of radiation oncology for the treatment of brain and extracranial lesions. Along with the evolution of other methods of radiotherapy, this type of treatment has been associated with significant advances in terms of a variety of modalities and techniques to improve the accuracy and efficacy of treatment. This paper provides a comprehensive overview of the progress in stereotactic radiosurgery (SRS) over several decades, and includes a review of various articles and research papers, commencing with the emergence of stereotactic techniques in radiotherapy. Key clinical aspects of SRS, such as fixation methods, radiobiology considerations, quality assurance practices, and treatment planning strategies, are presented. In addition, the review highlights the technological advancements in treatment modalities, encompassing the transition from cobalt-based systems to linear accelerator-based modalities. By addressing these topics, this study aims to offer insights into the advancements that have shaped the field of SRS, that have ultimately enhanced the accuracy and effectiveness of treatment.
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Affiliation(s)
- Navid Khaledi
- Department of Medical Physics, Cancer Care Manitoba, Winnipeg, MB, Canada
| | - Rao Khan
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
- Department of Physics and Astronomy and Department of Radiation Oncology, Howard University, Washington, District of Columbia, USA
| | - James L. Gräfe
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
- Cancer Care Program, Dr. H. Bliss Murphy Cancer Center. 300 Prince Philip Drive St. John’s, NL, Canada
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Yadav P, Pankuch M, McCorkindale J, Mitra RK, Rouse L, Khelashvili G, Mittal BB, Das IJ. Dosimetric evaluation of high-Z inhomogeneity with modern algorithms: A collaborative study. Phys Med 2023; 112:102649. [PMID: 37544030 DOI: 10.1016/j.ejmp.2023.102649] [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: 04/12/2023] [Revised: 07/12/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
PURPOSE To evaluate modern dose calculation algorithms with high-Z prosthetic devices used in radiation treatment. METHODS A bilateral hip prosthetic patient was selected to see the effect of modern algorithms from the commercial system for plan comparisons. The CT data with dose constraints were sent to various institutions for dose calculations. The dosimetric parameters, D98%, D90%, D50% and D2% were compared. A water phantom with an actual prosthetic device was used to measure the dose using a parallel plate ionization chamber. RESULTS Dosimetric variability in PTV coverage was significant (>10%) among various treatment planning algorithms. The comparison of PTV dosimetric parameters, D98%, D90%, D50% and D2% as well as organs at risk (OAR) have large discrepancies compared to our previous publication with older algorithms (https://doi.org/10.1016/j.ejmp.2022.02.007) but provides realistic dose distribution with better homogeneity index (HI). Backscatter and forward scatter attenuation of the prosthesis was measured showing differences <15.7% at the interface among various algorithms. CONCLUSIONS Modern algorithms dose distributions have improved greatly compared to older generation algorithms. However, there is still significant differences at high-Z-tissue interfaces compared to the measurements. To ensure accuracy, it's important to take precautions avoiding placing any prosthesis in the beam direction and using type C algorithms.
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Affiliation(s)
- Poonam Yadav
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mark Pankuch
- Northwestern Medicine Chicago Proton Center, 4455 Weaver Parkway, Warrenville, IL 60555, USA
| | - John McCorkindale
- Department of Radiation and Cellular Oncology, Northwestern Medicine 1000 N Westmoreland Rd, Lake Forest, IL 60045, USA
| | - Raj K Mitra
- Department of Radiation Oncology, Ochsner Health System, New Orleans, LA 7012, USA
| | - Luther Rouse
- Philips Healthcare, 100 Park Ave, Beachwood, OH 44122, USA
| | - Gocha Khelashvili
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Bharat B Mittal
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Indra J Das
- Department of Radiation Oncology, Northwest Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Ghemiș DM, Marcu LG, Virag V, Virag A. Dosimetric characteristics of 6MV flattening filter free and flattened beams among beam-matched linacs: a three-institutional study. Radiat Oncol 2023; 18:126. [PMID: 37507741 PMCID: PMC10375603 DOI: 10.1186/s13014-023-02313-5] [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: 02/02/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Beam matching is a concept in radiotherapy applied to clinics where more than one linac is employed to harmonise beam characteristics across linacs for allowing patients interchange without replanning. In view of this, the current study analyzes and compares dosimetric characteristics of 6MV flattening filter free and flattened beams of three beam-matched linear accelerators (linacs) from three different clinics with the aim to evaluate the matching under tight criteria for gamma analysis. METHODS Three Elekta linacs from three different clinics were included. The linacs have the same collimator assembly, Elekta Agility. Beam data were collected during commissioning process using PTW dosimetry systems. Dose profiles and percentage depth doses (PDD) were analyzed using 1D gamma analysis (1 mm/1%) as well as the following parameters: depth of maximum dose, PDD10, flatness, unflattnes, symmetry, penumbra, output factors. Additionally, five stereotactic treatment plans were optimized in one clinic and calculated by all three planning systems (Monaco) for a dosimetric comparison. RESULTS Gamma analysis of dose profiles and PDDs showed clinically acceptable results of 96.3% passing rate for profiles and 100% passing rate for PDDs. All dosimetric parameters were in good agreement with the reference data. Furthermore, dosimetric comparisons between stereotactic treatment plans showed a maximum standard deviation of 0.48 Gy for the maximum dose to PTV, and a maximum standard deviation of 0.1 Gy for the dose to the organs at risk. CONCLUSIONS All three linacs showed a strong agreement between parameters and passed the gamma analysis using 1% DD/1mm DTA criteria. This study confirmed the matching between linacs, offering the possibility to interchange patients with no replanning.
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Affiliation(s)
- Diana M Ghemiș
- Faculty of Physics, West University of Timisoara, Timisoara, Romania.
- MedEuropa, Oradea, 410191, Romania.
| | - Loredana G Marcu
- Faculty of Physics, West University of Timisoara, Timisoara, Romania
- Faculty of Informatics & Science, University of Oradea, Oradea, 410087, Romania
- UniSA Allied Health & Human Performance, University of South Australia, Adelaide, SA, 5001, Australia
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Manco L, Vega K, Maffei N, Gutierrez MV, Cenacchi E, Bernabei A, Bruni A, D'angelo E, Meduri B, Lohr F, Guidi G. Validation of RayStation Monte Carlo dose calculation algorithm for multiple LINACs. Phys Med 2023; 109:102588. [PMID: 37080156 DOI: 10.1016/j.ejmp.2023.102588] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 03/29/2023] [Accepted: 04/10/2023] [Indexed: 04/22/2023] Open
Abstract
PURPOSE A photon Monte Carlo (MC) model was commissioned for flattened (FF) and flattening filter free (FFF) 6 MV beam energy. The accuracy of this model, as a single model to be used for three beam matched LINACs, was evaluated. METHODS Multiple models were created in RayStation v.10A for three linacs equipped with Elekta "Agility" collimator. A clinically commissioned collapsed cone (CC) algorithm (GoldCC), a MC model automatically created from the CC algorithm without further optimization (CCtoMC) and an optimized MC model (GoldMC) were compared with measurements. The validation of the model was performed by following the recommendations of IAEA TRS 430 and comprised of basic validation in a water tank, validation in a heterogeneous phantom and validation of complex IMRT/VMAT paradigms using gamma analysis of calculated and measured dose maps in a 2D-Array. RESULTS Dose calculation with the GoldMC model resulted in a confidence level of 3% for point measurements in water tank and heterogeneous phantom for measurements performed in all three linacs. The same confidence level resulted for GoldCC model. Dose maps presented an agreement for all models on par to each other with γ criteria 2%/2mm. CONCLUSIONS The GoldMC model showed a good agreement with measured data and is determined to be accurate for clinical use for all three linacs in this study.
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Affiliation(s)
- Luigi Manco
- Medical Physics Unit, University Hospital of Modena, 41125 Modena, Italy; Medical Physics Unit, Azienda USL of Ferrara, 44124 Ferrara, Italy.
| | - Kevin Vega
- International Center of Theoretical Physics, Trieste, Italy; Centro Nacional de Radioterapia, Physics Unit, San Salvador, El Salvador
| | - Nicola Maffei
- Medical Physics Unit, University Hospital of Modena, 41125 Modena, Italy
| | | | - Elisa Cenacchi
- Medical Physics Unit, University Hospital of Modena, 41125 Modena, Italy
| | - Annalisa Bernabei
- Medical Physics Unit, University Hospital of Modena, 41125 Modena, Italy
| | - Alessio Bruni
- Radiation Therapy Unit, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy
| | - Elisa D'angelo
- Radiation Therapy Unit, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy
| | - Bruno Meduri
- Radiation Therapy Unit, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy
| | - Frank Lohr
- Radiation Therapy Unit, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy
| | - Gabriele Guidi
- Medical Physics Unit, University Hospital of Modena, 41125 Modena, Italy
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Saini A, Verma T, Pandey VP, Singh A, Kumar P. Performance evaluation of Monaco radiotherapy treatment planning system using CIRS Thorax Phantom: Dosimetric assessment of flattened and non-flattened photon beams. J Cancer Res Ther 2023; 19:793-800. [PMID: 37470613 DOI: 10.4103/jcrt.jcrt_967_21] [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] [Indexed: 07/21/2023]
Abstract
Aim The present study was undertaken to evaluate the performance of different algorithms for flattening filter-free (FFF) and flattened (FF) photon beams in three different in-homogeneities. Materials and Method Computed tomography (CT) image sets of the CIRS phantom maintained in the SAD setup by placing the ionization chamber in the lung, bone, and tissue regions, respectively, were acquired. The treatment planning system (TPS) calculated and the ionization chamber measured the doses at the center of the chamber (in the three mediums) were recorded for the flattened and non-flattened photon beams. Results The results were reported for photon energies of 6 MV, 10 MV, 15 MV, 6 FFF, and 10 FFF of field sizes 5 × 5 cm2, 10 × 10 cm2, and 15 × 15 cm2. In the bone inhomogeneity, the pencil beam algorithm predicted that the maximum dose variation was 4.88% of measured chamber dose in 10-MV photon energy for the field size 10 × 10 cm2. In water inhomogeneity, both the collapsed cone and Monte Carlo algorithm predicted that the maximum dose variation was ± 3% of measured chamber dose in 10-MV photon energy for the field size 10 × 10 cm2 and in 10-MV FFF photon energy for the field size 5 × 5 cm2, whereas in lung inhomogeneity, the pencil beam algorithm predicted that the highest dose variation was - 6.9% of measured chamber dose in 10-MV FFF photon energy for the field size 5 × 5 cm2. Conclusion FF and FFF beams performed differently in lung, water, and bone mediums. The assessment of algorithms was conducted using the anthropomorphic phantom; therefore, these findings may help in the selection of appropriate algorithms for particular clinical settings in radiation delivery.
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Affiliation(s)
- Amit Saini
- Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab; Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
| | - Teerthraj Verma
- Department of Radiotherapy, King George Medical University, Lucknow, Uttar Pradesh, India
| | - V P Pandey
- Department of Medical Physics, Hind Institute of Medical Sciences, Safedabad, Barabanki, Uttar Pradesh, India
| | - Avtar Singh
- Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab; Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
| | - Pankaj Kumar
- Chitkara University Institute of Engineering and Technology; Centre for Liquid Crystal Research, Chitkara University Research and Innovation Network, Chitkara University, Punjab, India
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Fix MK, Frei D, Mueller S, Guyer G, Loebner HA, Volken W, Manser P. Auto-commissioning of a Monte Carlo electron beam model with application to photon MLC shaped electron fields. Phys Med Biol 2023; 68. [PMID: 36716491 DOI: 10.1088/1361-6560/acb755] [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: 09/30/2022] [Accepted: 01/30/2023] [Indexed: 02/01/2023]
Abstract
Objective.Presently electron beam treatments are delivered using dedicated applicators. An alternative is the usage of the already installed photon multileaf collimator (pMLC) enabling efficient electron treatments. Currently, the commissioning of beam models is a manual and time-consuming process. In this work an auto-commissioning procedure for the Monte Carlo (MC) beam model part representing the beam above the pMLC is developed for TrueBeam systems with electron energies from 6 to 22 MeV.Approach.The analytical part of the electron beam model includes a main source representing the primary beam and a jaw source representing the head scatter contribution each consisting of an electron and a photon component, while MC radiation transport is performed for the pMLC. The auto-commissioning of this analytical part relies on information pre-determined from MC simulations, in-air dose profiles and absolute dose measurements in water for different field sizes and source to surface distances (SSDs). For validation calculated and measured dose distributions in water were compared for different field sizes, SSDs and beam energies for eight TrueBeam systems. Furthermore, a sternum case in an anthropomorphic phantom was considered and calculated and measured dose distributions were compared at different SSDs.Main results.Instead of the manual commissioning taking up to several days of calculation time and several hours of user time, the auto-commissioning is carried out in a few minutes. Measured and calculated dose distributions agree generally within 3% of maximum dose or 2 mm. The gamma passing rates for the sternum case ranged from 96% to 99% (3% (global)/2 mm criteria, 10% threshold).Significance.The auto-commissioning procedure was successfully implemented and applied to eight TrueBeam systems. The newly developed user-friendly auto-commissioning procedure allows an efficient commissioning of an MC electron beam model and eases the usage of advanced electron radiotherapy utilizing the pMLC for beam shaping.
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Affiliation(s)
- M K Fix
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - D Frei
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - S Mueller
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - G Guyer
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - H A Loebner
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - W Volken
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
| | - P Manser
- Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland
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Rostami A, Neto AJDC, Paloor SP, Khalid AS, Hammoud R. Comparison of four commercial dose calculation algorithms in different evaluation tests. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2023; 31:1013-1033. [PMID: 37393487 DOI: 10.3233/xst-230079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2023]
Abstract
BACKGROUND Accurate and fast dose calculation is crucial in modern radiation therapy. Four dose calculation algorithms (AAA, AXB, CCC, and MC) are available in Varian Eclipse and RaySearch Laboratories RayStation Treatment Planning Systems (TPSs). OBJECTIVES This study aims to evaluate and compare dosimetric accuracy of the four dose calculation algorithms applying to homogeneous and heterogeneous media, VMAT plans (based on AAPM TG-119 test cases), and the surface and buildup regions. METHODS The four algorithms are assessed in homogeneous (IAEA-TECDOCE 1540) and heterogeneous (IAEA-TECDOC 1583) media. Dosimetric evaluation accuracy for VMAT plans is then analyzed, along with the evaluation of the accuracy of algorithms applying to the surface and buildup regions. RESULTS Tests conducted in homogeneous media revealed that all algorithms exhibit dose deviations within 5% for various conditions, with pass rates exceeding 95% based on recommended tolerances. Additionally, the tests conducted in heterogeneous media demonstrate high pass rates for all algorithms, with a 100% pass rate observed for 6 MV and mostly 100% pass rate for 15 MV, except for CCC, which achieves a pass rate of 94%. The results of gamma index pass rate (GIPR) for dose calculation algorithms in IMRT fields show that GIPR (3% /3 mm) for all four algorithms in all evaluated tests based on TG119, are greater than 97%. The results of the algorithm testing for the accuracy of superficial dose reveal variations in dose differences, ranging from -11.9% to 7.03% for 15 MV and -9.5% to 3.3% for 6 MV, respectively. It is noteworthy that the AXB and MC algorithms demonstrate relatively lower discrepancies compared to the other algorithms. CONCLUSIONS This study shows that generally, two dose calculation algorithms (AXB and MC) that calculate dose in medium have better accuracy than other two dose calculation algorithms (CCC and AAA) that calculate dose to water.
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Affiliation(s)
- Aram Rostami
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | | | - Satheesh Prasad Paloor
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | - Abdul Sattar Khalid
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
| | - Rabih Hammoud
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar
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Dosimetric evaluation of a treatment planning system using the AAPM Medical Physics Practice Guideline 5.a (MPPG 5.a) validation tests. Phys Eng Sci Med 2022; 45:1341-1353. [PMID: 36352316 DOI: 10.1007/s13246-022-01194-4] [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: 10/26/2021] [Accepted: 10/21/2022] [Indexed: 11/11/2022]
Abstract
Verifying the accuracy of the dose calculation algorithm is considered one of the most critical steps in radiotherapy treatment for delivering an accurate dose to the patient. This work aimed to evaluate the dosimetric performance of the treatment planning system (TPS) algorithms; the AAA (v. 15.6), AXB (v. 15.6) and eMC (v. 15.6) following the AAPM medical physics practice guideline 5.a (MPPG 5.a) validation tests package in a Varian iX Linear Accelerator (Linac). A series of tests were developed based on the MPPG 5.a. on a Varian's Eclipse TPS (v. 15.6) (Varian Medical Systems). First, the basic photon and electron tests were validated by comparing the TPS calculated dose with the measurements. Next, for heterogeneity tests, we verified the Computed Tomography number to electron density (CT-to-ED) curve by comparing it with the baseline values, and TPS calculated point doses beyond heterogeneous media were compared to the measurements. Finally, for IMRT/VMAT dose validation tests, clinical reference plans were re-calculated on ArcCheck's virtual phantom (Sun Nuclear Corporation, Melbourne, FL, USA) and exported to the Linac for delivery using the ArcCheck dosimetry system. All validation tests were evaluated following the MPPG 5.a recommended tolerances. In basic dose validation tests, the TPS calculated depth dose profiles agreed well with the measurements, with a minimum gamma passing rate of 95% at 2%/2 mm criteria. However, disagreements are seen in the build-up and penumbra region. Results for most point doses in homogeneous water phantoms were within the MPPG 5.a tolerance. For the heterogeneity tests, the CT-to-ED curve was established, and calculated point doses were all within 3% of the measurements for heterogeneous media for both photon algorithms at three energies. These results are within the MPPG5.a the recommended tolerance of 3%. Moreover, for electron beams, the differences between the calculated and measured point doses averaged 5% and 7%, but were just within the MPPG 5.a tolerance of 7%. For IMRT and VMAT validation tests using a gamma criteria of a 2%/2 mm, IMRT plans showed maximum and minimum passing rates of 98.2% and 97.4%, respectively. Whereas VMAT plans showed maximum and minimum passing rates of 100% and 94.3%, respectively. We conclude that the dosimetric accuracy of the Eclipse TPS (v15.6) algorithm is adequate for clinical use. The MPPG 5.a tests are valuable for evaluating dose calculation accuracy and are very useful for TPS upgrade checks, commissioning tests, and routine TPS QA.
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Snyder JE, St-Aubin J, Yaddanapudi S, Marshall S, Strand S, Kruger S, Flynn R, Hyer DE. Reducing MRI-guided radiotherapy planning and delivery times via efficient leaf sequencing and segment shape optimization algorithms. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac5299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/07/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. Extended treatment session times are an operational limitation in magnetic resonance imaging guided adaptive radiotherapy (MRIgRT). In this study a novel leaf sequencing algorithm called optimal fluence levels (OFL) and an optimization algorithm called pseudo gradient descent (PGD) are evaluated with respect to plan quality, beam complexity, and the ability to reduce treatment session times on the Elekta Unity MRIgRT system. Approach. Ten total patients were evaluated on this Institutional Review Board approved study: three with prostate cancer, three with oligometastases, two with pancreatic cancer, and two with liver cancer. Plans were generated using the clinical Monaco Hyperion optimizer and leaf sequencer and then re-optimized using OFL and PGD (OFL + PGD) while holding all IMRT constraints and planning parameters constant. All plans were normalized to ensure 95% of the PTV received the prescription dose. A paired t-test was used to evaluate statistical significance. Main Results. Plan quality in terms of dosimetric OAR sparing was found to be equivalent between the OFL + PGD and conventional Monaco Hyperion optimizer plans. The OFL + PGD plans had a reduction in optimization time of 51.4% ± 5.0% (p = 0.002) and reduction in treatment delivery time of 10.6% ± 7.5% (p = 0.005). OFL + PGD generated plans had on average 13.2% ± 12.6% fewer multi-leaf collimator (MLC) segments (p = 0.009) and 0.1 ± 0.1 lower plan averaged beam modulation (PM) (p = 0.004) relative to the Monaco Hyperion plans. Significance. The OFL + PGD algorithms more quickly generate Unity treatment plans that are faster to deliver than with the conventional approach and without compromising dosimetric plan quality. This is likely due to a delivery complexity reduction enabled by OFL + PGD relative to the Monaco Hyperion plans.
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Feygelman V, Latifi K, Bowers M, Greco K, Moros EG, Isacson M, Angerud A, Caudell J. Maintaining dosimetric quality when switching to a Monte Carlo dose engine for head and neck volumetric-modulated arc therapy planning. J Appl Clin Med Phys 2022; 23:e13572. [PMID: 35213089 PMCID: PMC9121035 DOI: 10.1002/acm2.13572] [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: 08/18/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 11/13/2022] Open
Abstract
Head and neck cancers present challenges in radiation treatment planning due to the large number of critical structures near the target(s) and highly heterogeneous tissue composition. While Monte Carlo (MC) dose calculations currently offer the most accurate approximation of dose deposition in tissue, the switch to MC presents challenges in preserving the parameters of care. The differences in dose‐to‐tissue were widely discussed in the literature, but mostly in the context of recalculating the existing plans rather than reoptimizing with the MC dose engine. Also, the target dose homogeneity received less attention. We adhere to strict dose homogeneity objectives in clinical practice. In this study, we started with 21 clinical volumetric‐modulated arc therapy (VMAT) plans previously developed in Pinnacle treatment planning system. Those plans were recalculated “as is” with RayStation (RS) MC algorithm and then reoptimized in RS with both collapsed cone (CC) and MC algorithms. MC statistical uncertainty (0.3%) was selected carefully to balance the dose computation time (1–2 min) with the planning target volume (PTV) dose‐volume histogram (DVH) shape approaching that of a “noise‐free” calculation. When the hot spot in head and neck MC‐based treatment planning is defined as dose to 0.03 cc, it is exceedingly difficult to limit it to 105% of the prescription dose, as we were used to with the CC algorithm. The average hot spot after optimization and calculation with RS MC was statistically significantly higher compared to Pinnacle and RS CC algorithms by 1.2 and 1.0 %, respectively. The 95% confidence interval (CI) observed in this study suggests that in most cases a hot spot of ≤107% is achievable. Compared to the 95% CI for the previous clinical plans recalculated with RS MC “as is” (upper limit 108%), in real terms this result is at least as good or better than the historic plans.
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Affiliation(s)
- Vladimir Feygelman
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Kujtim Latifi
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Mark Bowers
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Kevin Greco
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Eduardo G Moros
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Max Isacson
- RaySearch Laboratories AB, Stockholm, Sweden
| | | | - Jimmy Caudell
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida, USA
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13
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Beam modeling and commissioning for Monte Carlo photon beam on an Elekta Versa HD LINAC. Appl Radiat Isot 2021; 180:110054. [PMID: 34875475 DOI: 10.1016/j.apradiso.2021.110054] [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: 03/08/2021] [Revised: 11/23/2021] [Accepted: 11/28/2021] [Indexed: 11/22/2022]
Abstract
PURPOSE This study aims at analyzing beam data commissioning along with verifying Monte Carlo-based treatment planning system on the basis of the manufacturer guidelines for Elekta Versa HD Linear Accelerator. Moreover, evaluating the beam match process in terms of quality index, photon profile and multi leaf collimator (MLC) offset is aimed as well. MATERIALS AND METHODS The process of collecting beam data for Monaco 5.51 Treatment Planning System commissioning was done based on the instructions provided by the manufacturer as well as AAPM TG-106. Monte Carlo analysis was done for output factors in water, percent depth dose and beam profiles. A set of eight static and intensity modulated radiation therapy fields were used to verify the MLC parameters. RESULTS The difference between the measured and modeled penetrative quality (D10) was achieved to be 0.54%. The output factors for 6 MV photon energy were measured and the difference between the measured and Monte Carlo output results was smaller than 1% for all the fields. The average percentage of passing the gamma criteria for commissioning test fields was (95+-4)%, however, the minimum agreement was 87.5% belonging to "7SEGA". Additionally, the agreement between both LINAC is 96%, however, the second LINAC reveals a positive offset in the point of approximately -4 cm on the x-axis at the crossplane. CONCLUSION Test commissioning was successfully verified using a homogeneous phantom for point dose measurements, post modelling MLC parameters and patient QA plans. All plan parameters pass the gamma criteria. 6 MV photon beam was successfully commissioned for Elekta VersaHD LINAC and is ready for clinical implementation.
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14
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Ferrer C, Huertas C, Plaza R, de la Monja P, Ocanto A, Escribano A, Pérez A, Sáez M. Simple template-based optimization for pediatric total lymphoid irradiation (TLI) radiotherapy treatments. Med Dosim 2021; 46:201-207. [PMID: 33309515 DOI: 10.1016/j.meddos.2020.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/27/2020] [Accepted: 11/18/2020] [Indexed: 10/22/2022]
Abstract
Total lymphoid irradiation (TLI) is used in the management of pediatric allogeneic hematopoietic stem cell transplantation (HSCT. This work aims to simplify the treatment planning process for TLI via a proposed template using the volumetric modulated arc therapy (VMAT) technique. Fifteen pediatric patients were planned, prescribed to 8 Gy in 4 fractions. Cost functions included in the template were the ones for the planning target volume (PTV), and conformality cost function (CCF) for the rest of the patient's volume. Conformity index (CI), homogeneity index (HI), conformation number (CN), gradient index (GI), integral dose, and doses to the organs at risk achieved with the template were reported. Cost function influence over various indexes was studied by Wilcoxon signed ranks test. Same 15 patients were planned with 3-dimensional conventional radiotherapy (3D-CRT) technique for comparison. Mean CI and HI were 1.33 and 0.13, respectively, which indicates good dose conformation and homogeneity. Mean CN and GI values were 0.69 and 4.51, respectively. Mean PTV coverage was reached (V100% > 95%). No correlation between the CCF and indexes values was found (p > 0.05). Doses to organs at risk (OARs) were as low as possible without losing PTV coverage. VMAT plan showed higher levels of conformation and similar homogeneity as 3D-CRT plans. Doses to OARs were inferior with VMAT except for the right kidney. The proposed template simplifies the planning of TLI treatments, and it is able to create acceptable plans with little modification in order to reduce doses to certain organs like the kidneys or the heart. VMAT technique showed higher conformation and lower doses to OAR compared to 3D-CRT.
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Affiliation(s)
- C Ferrer
- Department of Medical Physics and Radiation Protection, Hospital Universitario La Paz, Madrid, Spain.
| | - C Huertas
- Department of Medical Physics and Radiation Protection, Hospital Universitario La Paz, Madrid, Spain
| | - R Plaza
- Department of Medical Physics and Radiation Protection, Hospital Universitario La Paz, Madrid, Spain
| | - P de la Monja
- Department of Medical Physics and Radiation Protection, Hospital Universitario La Paz, Madrid, Spain
| | - A Ocanto
- Radiation Oncology Department, Hospital Universitario La Paz, Madrid, Spain
| | - A Escribano
- Radiation Oncology Department, Hospital Universitario La Paz, Madrid, Spain
| | - A Pérez
- Pediatric Hematology-Oncology Department, Hospital Universitario La Paz, Madrid, Spain
| | - M Sáez
- Department of Medical Physics and Radiation Protection, Hospital Universitario La Paz, Madrid, Spain
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15
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Neutron and photon out-of-field doses at cardiac implantable electronic device (CIED) depths. Appl Radiat Isot 2021; 176:109895. [PMID: 34419874 DOI: 10.1016/j.apradiso.2021.109895] [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: 12/23/2020] [Revised: 08/08/2021] [Accepted: 08/08/2021] [Indexed: 11/20/2022]
Abstract
The accuracy of an out-of-field dose from an Elekta Synergy accelerator calculated using the X-ray Voxel Monte Carlo (XVMC) dose algorithm in the Monaco treatment planning system (TPS) for both low-energy (6 MV) and high-energy (15 MV) photons at cardiac implantable electronic device (CIED) depths was investigated through a comparison between MCNPX simulated out-of-field doses and measured out-of-field doses using three high spatial and sensitive active detectors. In addition, total neutron equivalent dose and fluence at CIED depths of a 15-MV dose from an Elekta Synergy accelerator were calculated, and the corresponding CIED relative neutron damage was quantified. The results showed that for 6-MV photons, the XVMC dose algorithm in Monaco underestimated out-of-field doses in all off-axis distances (average errors: -17% at distances X < 10 cm from the field edge and -31% at distances between 10 < X ≤ 16 cm from the field edge), with an increasing magnitude of underestimation for high-energy (15 MV) photons (up to 11%). According to the results, an out-of-field photon dose at a shallower CIED depth of 1 cm was associated with greater statistical uncertainty in the dose estimate compared to a CIED depth of 2 cm and clinical depth of 10 cm. Our results showed that the relative neutron damage at a CIED depth range for 15 MV photon is 36% less than that reported for 18 MV photon in the literature.
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16
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Dose Calculation Algorithms for External Radiation Therapy: An Overview for Practitioners. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11156806] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Radiation therapy (RT) is a constantly evolving therapeutic technique; improvements are continuously being introduced for both methodological and practical aspects. Among the features that have undergone a huge evolution in recent decades, dose calculation algorithms are still rapidly changing. This process is propelled by the awareness that the agreement between the delivered and calculated doses is of paramount relevance in RT, since it could largely affect clinical outcomes. The aim of this work is to provide an overall picture of the main dose calculation algorithms currently used in RT, summarizing their underlying physical models and mathematical bases, and highlighting their strengths and weaknesses, referring to the most recent studies on algorithm comparisons. This handy guide is meant to provide a clear and concise overview of the topic, which will prove useful in helping clinical medical physicists to perform their responsibilities more effectively and efficiently, increasing patient benefits and improving the overall quality of the management of radiation treatment.
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17
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Strand S, Boczkowski A, Smith B, Snyder JE, Hyer DE, Yaddanapudi S, Dunkerley DAP, St‐Aubin J. Analysis of patient-specific quality assurance for Elekta Unity adaptive plans using statistical process control methodology. J Appl Clin Med Phys 2021; 22:99-107. [PMID: 33756059 PMCID: PMC8035570 DOI: 10.1002/acm2.13219] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 02/05/2021] [Accepted: 02/15/2021] [Indexed: 11/08/2022] Open
Abstract
The Elekta Unity MR-linac utilizes daily magnetic resonance imaging (MRI) for online plan adaptation. In the Unity workflow, adapt to position (ATP) and adapt to shape (ATS) treatment planning options are available which represent a virtual shift or full re-plan with contour adjustments respectively. Both techniques generate a new intensity modulated radiation therapy (IMRT) treatment plan while the patient lies on the treatment table and thus adapted plans cannot be measured prior to treatment delivery. A statistical process control methodology was used to analyze 512 patient-specific IMRT QA measurements performed on the MR-compatible SunNuclear ArcCheck with a gamma criterion of 3%/2 mm using global normalization and a 10% low dose threshold. The lower control limit (LCL) was determined from 68 IMRT reference plan measurements, and a one-sided process capability ratio ( C p , l ) was used to assess the pass rates from 432 measured ATP and 80 measured ATS plans. Further analysis was performed to assess differences between SBRT or conventional fractionation pass rates and to determine whether there was any correlation between the pass rates and plan complexity. The LCL of the reference plans was determined to be a gamma pass rate of 0.958, and the C p , l of the measured ATP plans and measured ATS plans were determined to be 1.403 and 0.940 for ATP and ATS plans, respectively, while a C p , l of 0.902 and 1.383 was found for SBRT and conventional fractionations respectively. For plan complexity, no correlation was found between modulation degree and gamma pass rate, but a statistically significant correlation was observed between the beam-averaged aperture area and gamma pass rate. All adaptive plans passed the TG-218 guidelines, but the ATS and SBRT plans tended to have a smaller beam-averaged aperture area with slightly lower gamma pass rates.
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Affiliation(s)
- Sarah Strand
- University of Iowa Hospitals and ClinicsIowa CityIAUSA
| | | | - Blake Smith
- University of Iowa Hospitals and ClinicsIowa CityIAUSA
| | | | | | | | | | - Joel St‐Aubin
- University of Iowa Hospitals and ClinicsIowa CityIAUSA
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18
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Duncan-Gelder P, Moggré A, Cousins A, Wilder B, Marsh S. Accurate dosimetric measurement of large extended SSD fields for comparison to TPS models. Phys Med 2021; 84:220-227. [PMID: 33741247 DOI: 10.1016/j.ejmp.2021.03.001] [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: 09/11/2020] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 10/21/2022] Open
Abstract
PURPOSE There is little evidence in the literature which quantifies the accuracy of Treatment Planning Systems (TPSs) using large fields at extended SSD (eSSD). This paper introduces the approach taken at Christchurch Hospital, New Zealand to validate the use of the Monaco TPS for Total Body Irradiation (TBI) treatments. METHODS A purpose-built device for allowing precise movements of block-like phantoms called a Phantom Mobility Device (PMD) was used for collecting measurements at eSSD. These measurements were used for determining the ability of the Monaco TPS (originally validated for SSDs between 80 and 110 cm) to accurately model dose distributions for TBI treatments at Christchurch Hospital on either treatment machine one (T1) or two (T2) with SSD values of 341 and 432.6 and clinically useful field sizes of 120 and 170 cm, respectively. RESULTS We found that within the limits of measurement uncertainty the PMD contributed no determinable scatter to the measurements and proved a reliable approach for eSSD dose measurements. Additionally, by applying depth and off-axis distance constraints of use for TPS information it is possible to use the existing Monaco CCC model at eSSD for block phantom geometries. Dose Difference (DD) analysis showed a clinically acceptable agreement between the CCC model and measured data over a range of depths and off-axis distances. CONCLUSIONS The PMD was determined to be a useful tool for accurate measurement of extended SSD treatment fields. Monaco TPS CCC model agreed well for block phantoms so future comparisons to anthropomorphic phantoms or patient data are feasible.
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Affiliation(s)
| | - Alicia Moggré
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Andrew Cousins
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Benjamin Wilder
- University of Canterbury and Canterbury District Health Board, New Zealand.
| | - Steven Marsh
- University of Canterbury and Canterbury District Health Board, New Zealand.
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19
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Felisi M, Monti AF, Lizio D, Nici S, Pellegrini RG, Riga S, Bortolato B, Brambilla MG, Carbonini C, Abujami M, Carsana C, Sibio D, Potente C, Vanzulli A, Palazzi MF, Torresin A. MRI only in a patient with prostate cancer with bilateral metal hip prostheses: case study. TUMORI JOURNAL 2021; 107:NP41-NP44. [PMID: 33629653 DOI: 10.1177/0300891621997549] [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] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To outline a practical method of performing prostate cancer radiotherapy in patients with bilateral metal hip prostheses with the standard resources available in a modern general hospital. The proposed workflow is based exclusively on magnetic resonance imaging (MRI) to avoid computed tomography (CT) artifacts. CASE DESCRIPTION This study concerns a 73-year-old man with bilateral hip prostheses with an elevated risk prostate cancer. Magnetic resonance images with assigned electron densities were used for planning purposes, generating a synthetic CT (sCT). Imaging acquisition was performed with an optimized Dixon sequence on a 1.5T MRI scanner. The images were contoured by autosegmentation software, based on an MRI database of 20 patients. The sCT was generated assigning averaged electron densities to each contour. Two volumetric modulated arc therapy plans, a complete arc and a partial one, where the beam entrances through the prostheses were avoided for about 50° on both sides, were compared. The feasibility of matching daily cone beam CT (CBCT) with MRI reference images was also tested by visual evaluations of different radiation oncologists. CONCLUSIONS The use of magnetic resonance images improved accuracy in targets and organs at risk (OARs) contouring. The complete arc plan was chosen because of 10% lower mean and maximum doses to prostheses with the same planning target volume coverage and OAR sparing. The image quality of the match between performed CBCTs and MRI was considered acceptable. The proposed method seems promising to improve radiotherapy treatments for this complex category of patients.
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Affiliation(s)
- Marco Felisi
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Angelo Filippo Monti
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Domenico Lizio
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Stefania Nici
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | | | - Stefano Riga
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Barbara Bortolato
- Radiotherapy Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | | | - Claudia Carbonini
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Mohammed Abujami
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Chiara Carsana
- Radiotherapy Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Daniela Sibio
- Radiotherapy Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Carmelina Potente
- Radiotherapy Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Angelo Vanzulli
- Radiology Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | | | - Alberto Torresin
- Medical Physics Department, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
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20
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Richmond N, Angerud A, Tamm F, Allen V. Comparison of the RayStation photon Monte Carlo dose calculation algorithm against measured data under homogeneous and heterogeneous irradiation geometries. Phys Med 2021; 82:87-99. [PMID: 33601165 DOI: 10.1016/j.ejmp.2021.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/02/2021] [Accepted: 02/06/2021] [Indexed: 10/22/2022] Open
Abstract
PURPOSE This work compares Monte Carlo dose calculations performed using the RayStation treatment planning system against data measured on a Varian Truebeam linear accelerator with 6 MV and 10 MV FFF photon beams. METHODS The dosimetric performance of the RayStation Monte Carlo calculations was evaluated in a variety of irradiation geometries employing homogeneous and heterogeneous phantoms. Profile and depth dose comparisons against measurement were carried out in relative mode using the gamma index as a quantitative measure of similarity within the central high dose regions. RESULTS The results demonstrate that the treatment planning system dose calculation engine agrees with measurement to within 2%/1 mm for more than 95% of the data points in the high dose regions for all test cases. A systematic underestimation was observed at the tail of the profile penumbra and out of field, with mean differences generally <0.5 mm or 1% of curve dose maximum respectively. Out of field agreement varied between evaluated beam models. CONCLUSIONS The RayStation implementation of photon Monte Carlo dose calculations show good agreement with measured data for the range of scenarios considered in this work and is deemed sufficiently accurate for introduction into clinical use.
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Affiliation(s)
- Neil Richmond
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK.
| | | | | | - Vincent Allen
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK
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21
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Chen J, Dai J, Nobah A, Bai S, Bi N, Lai Y, Li M, Tian Y, Wang X, Fu Q, Liang B, Zhang T, Xia W, Xu Y, Ren W, Yan X, Zhu J, Chen D, Yang J. A Special Report on 2019 International Planning Competition and a Comprehensive Analysis of Its Results. Front Oncol 2020; 10:571644. [PMID: 33344231 PMCID: PMC7746833 DOI: 10.3389/fonc.2020.571644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/30/2020] [Indexed: 02/05/2023] Open
Abstract
Purpose The aim of this work is to introduce the 2019 International Planning Competition and to analyze its results. Methods and materials A locally advanced non-small cell lung cancer (LA-NSCLC) case using the simultaneous integrated boost approach was selected. The plan quality was evaluated by using a ranking system in accordance with practice guidelines. Planners used their clinical Treatment Planning System (TPS) to generate the best possible plan along with a survey, designed to obtain medical physics aspects information. We investigated the quality of the large population of plans designed by worldwide planners using different planning and delivery systems. The correlations of plan quality with relevant planner characteristics (work experience, department scale, and competition experience) and with technological parameters (TPS and modality) were examined. Results The number of the qualified plans was 287 with a wide range of scores (38.61–97.99). The scores showed statistically significant differences by the following factors: 1) department scale: the mean score (89.76 ± 8.36) for planners from the departments treating >2,000 patients annually was the highest of all; 2) competition experience: the mean score for the 107 planners with previous competition experience was 88.92 ± 9.59, statistically significantly from first-time participants (p = .001); 3) techniques: the mean scores for planners using VMAT (89.18 ± 6.43) and TOMO (90.62 ± 7.60) were higher than those using IMRT (82.28 ± 12.47), with statistical differences (p <.001). The plan scores were negligibly correlated with the planner’s years of work experience or the type of TPS used. Regression analysis demonstrated that plan score was associated with dosimetric objectives that were difficult to achieve, which is generally consistent with a clinical practice evaluation. However, 51.2% of the planners abandoned the difficult component of total lung receiving a dose of 5 Gy in their plan design to achieve the optimal plan. Conclusion The 2019 international planning competition was carried out successfully, and its results were analyzed. Plan quality was not correlated with work experiences or the TPS used, but it was correlated with department scale, modality, and competition experience. These findings differed from those reported in previous studies.
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Affiliation(s)
- Jiayun Chen
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ahmad Nobah
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Sen Bai
- Department of Radiation Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Nan Bi
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Youqun Lai
- Department of Radiation Oncology, Fujian Medical University Xiamen Humanity Hospital, Xiamen, China
| | - Minghui Li
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuan Tian
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuetao Wang
- Department of Radiation Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Qi Fu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bin Liang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Zhang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wenlong Xia
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuan Xu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wenting Ren
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuena Yan
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ji Zhu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Deqi Chen
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiming Yang
- Department of Radiotherapy and Chemotherapy, Ningbo First Hospital, Ningbo, China
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22
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Assessing the accuracy of treatment planning system based radiotherapy structure volumes. JOURNAL OF RADIOTHERAPY IN PRACTICE 2020. [DOI: 10.1017/s1460396920000771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractAim:The purpose of the present study was to assess the accuracy of radiotherapy (RT) structure volume generated by the Monaco treatment planning system (TPS) for three different computed tomography (CT) slice thicknesses. Further, this study addressed the important issue of ‘different volumes of the same RT structure shown at different places’ in the Monaco TPS. Also, the practical impact of this difference in structure volumes has been studied for brain or head and neck patients.Materials and Methods:Objects of known volumes were scanned with different CT slice thicknesses and contoured as an RT structure in Monaco TPS and two different volumes provided by the TPS for each RT structure were noted and compared with the real volumes of these objects. In addition, correlation was also assessed between TPS provided volumes and real volumes of these objects. The study was further extended to obtain correlation of volumes in cases of organs that exist in pairs (e.g., eye) in the human body.Results:Monaco TPS overestimates structure volumes except for objects with sharp corners. Although, volumes shown at different places of the same structure have nearly a linear correlation, volumes under structure table are more accurate than those shown under dose–volume histogram (DVH) statistics (total volume) table. Difference in magnitude between these two volumes has no correlation if this difference is analysed for paired organs.Findings:This study confirmed that Monaco TPS provides ‘different value at different places’ of the volume of a given contoured structure. It is recommended that this issue should be reviewed and resolved by the supplier.
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23
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Snyder JE, St-Aubin J, Yaddanapudi S, Boczkowski A, Dunkerley DAP, Graves SA, Hyer DE. Commissioning of a 1.5T Elekta Unity MR-linac: A single institution experience. J Appl Clin Med Phys 2020; 21:160-172. [PMID: 32432405 PMCID: PMC7386194 DOI: 10.1002/acm2.12902] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/17/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
MR image-guided radiotherapy has the potential to improve patient care, but integration of an MRI scanner with a linear accelerator adds complexity to the commissioning process. This work describes a single institution experience of commissioning an Elekta Unity MR-linac, including mechanical testing, MRI scanner commissioning, and dosimetric validation. Mechanical testing included multileaf collimator (MLC) positional accuracy, measurement of radiation isocenter diameter, and MR-to-MV coincidence. Key MRI tests included magnetic field homogeneity, geometric accuracy, image quality, and the accuracy of navigator-triggered imaging for motion management. Dosimetric validation consisted of comparison between measured and calculated PDDs and profiles, IMRT measurements, and end-to-end testing. Multileaf collimator positional accuracy was within 1.0 mm, the measured radiation isocenter walkout was 0.20 mm, and the coincidence between MR and MV isocenter was 1.06 mm, which is accounted for in the treatment planning system (TPS). For a 350-mm-diameter spherical volume, the peak-to-peak deviation of the magnetic field homogeneity was 4.44 ppm and the geometric distortion was 0.8 mm. All image quality metrics were within ACR recommendations. Navigator-triggered images showed a maximum deviation of 0.42, 0.75, and 3.0 mm in the target centroid location compared to the stationary target for a 20 mm motion at 10, 15, and 20 breaths per minute, respectively. TPS-calculated PDDs and profiles showed excellent agreement with measurement. The gamma passing rate for IMRT plans was 98.4 ± 1.1% (3%/ 2 mm) and end-to-end testing of adapted plans showed agreement within 0.4% between ion-chamber measurement and TPS calculation. All credentialing criteria were satisfied in an independent end-to-end test using an IROC MRgRT phantom.
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Affiliation(s)
- Jeffrey E Snyder
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
| | - Joël St-Aubin
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
| | | | - Amanda Boczkowski
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
| | | | | | - Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
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24
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A convolution neural network for higher resolution dose prediction in prostate volumetric modulated arc therapy. Phys Med 2020; 72:88-95. [DOI: 10.1016/j.ejmp.2020.03.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/21/2020] [Accepted: 03/26/2020] [Indexed: 12/31/2022] Open
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