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Plaza D, Sroka Ł, Orzechowska K, Ślosarek K. Comparison of the dose distribution of the VMAT radiotherapy technique depending on the beam used: FFF-X10MV and FFF-X15MV. Rep Pract Oncol Radiother 2023; 28:654-660. [PMID: 38179296 PMCID: PMC10764046 DOI: 10.5603/rpor.97508] [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: 03/27/2023] [Accepted: 09/18/2023] [Indexed: 01/06/2024] Open
Abstract
Background The aim of the study was to answer the question of whether flattening filter (FF) and flattening filter-free (FFF) beams can be used alternately in the volumetric modulated arc therapy (VMAT) treatment technique, regardless of the size of the irradiated volume [small (S) or large (L) planning target volume (PTV)]. Materials and methods Two groups of patients were examined: a group with a S-PTV-laryngeal cancer and a group with a L-PTV - gynecological volume. For each patient, two treatment plans were made for beams (energies): FFF-X10MV and FF-X15MV. Then, a statistical analysis, nonparametric test, and independent groups were performed, comparing the beams' impact on the analyzed treatment plans. Results In the case of laryngeal irradiation (S-PTV), there are no statistically significant differences between the energy used and the assessed parameters of the plan. In the case of gynecological volume (L-PTV), only statistically significant differences were noted for the number of monitor units depending on the energy used. For a large irradiated volume (gynecological case), the use of FFF beams increases the number of monitor units by 39,4% in relation to the FF beam. Conclusions In the case of gynecological neoplasms, statistically significant differences were found in the number of monitor units. Therefore, in the case of irradiation of L-PTV, it is recommended that flattening-filtering beams are used due to the smaller number of monitors. In the case of S-PTV, no statistically significant differences were found between the types of beams used (FF or FFF) and the treatment plan parameters analyzed in the study.
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Affiliation(s)
- Dominika Plaza
- Radiotherapy Planning Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
| | - Łukasz Sroka
- Radiotherapy Planning Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
| | - Klaudia Orzechowska
- Radiotherapy Planning Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
| | - Krzysztof Ślosarek
- Radiotherapy Planning Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
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Ghemiş DM, Marcu LG. Progress and prospects of flattening filter free beam technology in radiosurgery and stereotactic body radiotherapy. Crit Rev Oncol Hematol 2021; 163:103396. [PMID: 34146680 DOI: 10.1016/j.critrevonc.2021.103396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/25/2022] Open
Abstract
The aim of this work is to summarize and evaluate the current status of knowledge on flattening filter free (FFF) beams and their applications in stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). A PubMed search was undertaken in order to identify relevant publications using FFF and stereotactic radiotherapy as keywords. On a clinical aspect, lung tumors treated with FFF SBRT show promising results in terms of local control and overall survival with acute toxicities consistent with those that occur with standard radiotherapy. Beside lung, SBRT is suitable for different anatomical sites such as liver, prostate, cervix, etc. offering similar results: reduced treatment time, good tumor control and mild acute toxicities. Regarding brain tumors, the employment of SRS with FFF beams significantly reduces treatment time and provides notable normal tissue sparing due to the sharp dose fall-off outside the tumor.
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Affiliation(s)
- Diana M Ghemiş
- West University of Timisoara, Faculty of Physics, Timisoara, Romania; MedEuropa, Oradea, Romania
| | - Loredana G Marcu
- West University of Timisoara, Faculty of Physics, Timisoara, Romania; Faculty of Informatics & Science, University of Oradea, Oradea, 410087, Romania; Cancer Research Institute, University of South Australia, Adelaide, SA, 5001, Australia.
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Effects of flattening filter (FF) and flattening filter-free (FFF) beams on small-field and large-field dose distribution using the VMAT treatment plan. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2021. [DOI: 10.2478/pjmpe-2021-0016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
Introduction: The aim of the study was to evaluate the influence of flattening filter (FF) and flattening filter-free (FFF) beams on small-field and large-field dose distribution using the VMAT treatment plan.
Material and methods: Dose distribution calculations were performed for the VMAT technique in two locations: the larynx (small irradiation field; average 30.1 cm2) and gynecology (large irradiation field; average 173.1 cm2) using X-6MV flattening filter (FF) and flattening filter-free (FFF) beams. The following values were compared: the number of monitor units, minimum doses, average doses in PTV and maximum average doses in OaR (spinal cord – in larynx radiotherapy, bladder and rectum - in gynecological radiotherapy) and RPI (Radiation Planning Index) coefficient.
Results and Discussion: The performed statistical tests indicate that there is a significant difference (p <0.05) between the number of monitor units in the irradiation of large (gynecological) fields between the FF and FFF beams. The dose distributions show no statistically significant differences between the flattening filter and flattening-free filter beams (regardless of the field size).
Conclusions: Due to the smaller number of monitor units, it is recommended to use flattening filter beams (FF) for large-field radiotherapy.
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Wang H, Chen K, Shi Y, Huang X, Sun W, Hou K, Jin Y, Jiang X, Yang D, Dong L. Technical Note: Induced radioactivity in stereotactic body radiation therapy with a flattening-filter-free 10 MV beam model. Med Phys 2021; 48:2010-2017. [PMID: 33524168 DOI: 10.1002/mp.14747] [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: 07/21/2020] [Revised: 11/11/2020] [Accepted: 01/25/2021] [Indexed: 01/03/2023] Open
Abstract
PURPOSE The induced radioactivity in stereotactic body radiation therapy with a flattening-filter-free 10 MV beam model (10 FFF SBRT) was investigated for the risk to therapists. METHODS This study was performed on a Varian TrueBeam linac. The induced radioisotopes were identified by γ spectroscopy. The dose rate from the induced activity was measured for 12 treatment cycles in 4 h continuously. The impacts of the characteristic factors of 10 FFF SBRT on the dose rate were investigated, including monitor units (MU), beam rate, field size, and flattening filter. The dose rate was compared between the SBRT plans and conventional fractionation plans. A mathematical model was used to analyze the results and estimate the annual dose to therapists. RESULTS (a) The induced radioisotopes included 24 Na, 28 Al, 38 Cl, 56 Mn, 66 Cu, 187 W, and 196 Au. (b) In 4 h, the total dose contribution ratios were more than 70% for 28 Al, about 20% for 56 Mn, and 10% for all other long-lived radioisotopes, combining doses at the isocenter and end of the treatment couch. (c) The dose rate showed a nonlinear growth with increasing MU and beam rate. The variation of the dose rate was complicated with the jaw field and not sensitive to the MLC field. The removal of the flattening filter reduced the dose rate by about 40%. The dose level of SBRT was two to three times that of conventional fractionation. (d) The estimated annual dose to therapists was up to 0.20 mSv/y. CONCLUSIONS The induced radioactivity in 10 FFF SBRT was higher compared with that in 10 MV conventional fractionation. More MU and higher beam rate were the primary factors that caused the increase. The therapists should wait longer after beam-off to reduce the occupational dose. In addition, aluminum and manganese should be less used in the treatment room.
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Affiliation(s)
- Huidong Wang
- Department of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China
| | - Kunzhi Chen
- Department of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China
| | - Yinghua Shi
- Department of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China
| | | | - Wuji Sun
- College of Physics, Jilin University, Changchun, China
| | - Kairan Hou
- College of Physics, Jilin University, Changchun, China
| | - Yongli Jin
- China Institute of Atomic Energy, Beijing, China
| | - Xin Jiang
- Department of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China
| | - Dong Yang
- College of Physics, Jilin University, Changchun, China
| | - Lihua Dong
- Department of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun, China
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Yada R, Maenaka K, Miyamoto S, Okada G, Sasakura A, Ashida M, Adachi M, Sato T, Wang T, Akasaka H, Mukumoto N, Shimizu Y, Sasaki R. Real-time in vivo dosimetry system based on an optical fiber-coupled microsized photostimulable phosphor for stereotactic body radiation therapy. Med Phys 2020; 47:5235-5249. [PMID: 32654194 DOI: 10.1002/mp.14383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/21/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
PURPOSE To develop an in vivo dosimeter system for stereotactic body radiation therapy (SBRT) that can perform accurate and precise real-time measurements, using a microsized amount of a photostimulable phosphor (PSP), BaFBr:Eu2+ . METHODS The sensitive volume of the PSP was 1.26 × 10-5 cm3 . The dosimeter system was designed to apply photostimulation to the PSP after the decay of noise signals, in synchronization with the photon beam pulse of a linear accelerator (LINAC), to eliminate the noise signals completely using a time separation technique. The noise signals included stem signals, and radioluminescence signals generated by the PSP. In addition, the dosimeter system was built on a storage-type dosimeter that could read out a signal after an arbitrary preset number of photon beam pulses were incident. First, the noise and photostimulated luminescence (PSL) signal decay times were measured. Subsequently, we confirmed that the PSL signals could be exclusively read out within the photon beam pulse interval. Finally, using a water phantom, the basic characteristics of the dosimeter system were demonstrated under SBRT conditions, and the feasibility for clinical application was investigated. The reproducibility, dose linearity, dose-rate dependence, temperature dependence, and angular dependence were evaluated. The feasibility was confirmed by measurements at various dose gradients and using a representative treatment plan for a metastatic liver tumor. A clinical plan was created with a two-arc beam volumetric modulated arc therapy using a 10 MV flattening filter-free photon beam. For the water phantom measurements, the clinical plan was compiled into a plan with a fixed gantry angle of 0°. To evaluate the energy dependence during SBRT, the percent depth dose (PDD) was measured and compared with those calculated via Monte Carlo (MC) simulations. RESULTS All the PSL signals could be read out while eliminating the noise signals within the minimum pulse interval of the LINAC. Stable real-time measurements could be performed with a time resolution of 56 ms (i.e., number of pulses = 20). The dose linearity was good in the dose range of 0.01-100 Gy. The measurements agreed within 1% at dose rates of 40-2400 cGy/min. The temperature and angular dependence were also acceptable since these dependencies had only a negligible effect on the measurements in SBRT. At a dose gradient of 2.21 Gy/mm, the measured dose agreed with that calculated using a treatment planning system (TPS) within the measurement uncertainties due to the probe position. For measurements using a representative treatment plan, the measured dose agreed with that calculated using the TPS within 0.5% at the center of the beam axis. The PDD measurements agreed with the MC calculations to within 1% for field sizes <5 × 5 cm2 . CONCLUSION The in vivo dosimeter system developed using BaFBr:Eu2+ is capable of real-time, accurate, and precise measurement under SBRT conditions. The probe is smaller than a conventional dosimeter, has excellent spatial resolution, and can be valuable in SBRT with a steep dose distribution over a small field. The developed PSP dosimeter system appears to be suitable for in vivo SBRT dosimetry.
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Affiliation(s)
- Ryuichi Yada
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Kazusuke Maenaka
- Department of Electrical Engineering and Computer Science, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan
| | - Shuji Miyamoto
- Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigoricho, Akogun, Hyogo, 678-1205, Japan
| | - Go Okada
- Co-creative Research Center of Industrial Science and Technology, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa, 924-0838, Japan
| | - Aki Sasakura
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Motoi Ashida
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Masashi Adachi
- Meisyo Kiko Co., Ltd, 148 Numa, Hikamicho, Tamba, Hyogo, 669-3634, Japan
| | - Tatsuhiko Sato
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Tianyuan Wang
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Hiroaki Akasaka
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Naritoshi Mukumoto
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Yasuyuki Shimizu
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Ryohei Sasaki
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
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