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Quoc SD, Fujibuchi T, Arakawa H, Hamada K. Simulating the head of a TrueBeam linear particle accelerator and calculating the photoneutron spectrum on the central axis of a 10-MV photon using particle and heavy-ion transport system code. RADIATION PROTECTION DOSIMETRY 2024; 200:779-790. [PMID: 38767288 DOI: 10.1093/rpd/ncae124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 03/15/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024]
Abstract
Photon energy is higher than the (γ,n) threshold, allowing it to interact with the nuclei of materials with high z properties and liberate fast neutrons. This represents a potentially harmful source of radiation for humans and the environment. This study validated the Monte Carlo simulation, using the particle and heavy-ion transport code system (PHITS) on a TrueBeam 10-MV linear particle accelerator's head shielding model and then used this PHITS code to simulate a photo-neutron spectrum for the transport of the beam. The results showed that, when comparing the simulated to measured PDD and crosslines, 100% of the γ-indexes were <1 (γ3%/3mm) for both simulations, for both phase-space data source and a mono energy source. Neutron spectra were recorded in all parts of the TrueBeam's head, as well as photon neutron spectra at three points on the beamline.
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Affiliation(s)
- Soai Dang Quoc
- Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Toshioh Fujibuchi
- Division of Medical Quantum Science, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Hiroyuki Arakawa
- Division of Medical Quantum Science, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Keisuke Hamada
- Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
- Department of Radiological Technology, National Hospital Organization Kyushu Cancer Center, 3-1-1 Notame Minami-ku, Fukuoka, Fukuoka 811-1395, Japan
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Brekner MC, Imhoff D, Rödel C, Filmann N, Licher J, Ramm U, Köhn J. Stereotactic body radiotherapy with volumetric intensity-modulated arc therapy and flattening filter-free beams: dosimetric considerations. Strahlenther Onkol 2024; 200:346-357. [PMID: 38092967 DOI: 10.1007/s00066-023-02181-8] [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: 07/27/2023] [Accepted: 11/01/2023] [Indexed: 03/27/2024]
Abstract
PURPOSE The present study comparatively evaluates the impact of energy-matched flattening filter-free (FFF) photon beams with different energy levels on the physical-dosimetric quality of lung and liver stereotactic body radiotherapy (SBRT) treatment plans. METHODS For this purpose, 54 different lung and liver lesions from 44 patients who had already received SBRT combined with volumetric modulated arc therapy (VMAT) were included in this retrospective planning study. Planning computed tomography scans already available were used for the renewed planning with 6 MV, 6 MV-FFF, 10 MV, and 10 MV-FFF under constant planning objectives. The treatment delivery data, dosimetric distributions, and dose-volume histograms as well as parameters such as the conformity index and gradient indices were the basis for the evaluation and comparison of treatment plans. RESULTS A significant reduction of beam-on time (BOT) was achieved due to the high dose rates of FFF beams. In addition, we showed that for FFF beams compared to flattened beams of the same energy level, smaller planning target volumes (PTV) require fewer monitor units (MU) than larger PTVs. An equal to slightly superior target volume coverage and sparing of healthy tissue as well as organs at risk in both lung and liver lesions were found. Significant differences were seen mainly in the medium to lower dose range. CONCLUSION We found that FFF beams together with VMAT represent an excellent combination for SBRT of lung or liver lesions with shortest BOT for 10 MV-FFF but significant dose savings for 6 MV-FFF in lung lesions.
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Affiliation(s)
- Mark Christoph Brekner
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany.
| | - Detlef Imhoff
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Claus Rödel
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Natalie Filmann
- Institute for Biostatistics and Mathematical Modeling, University Hospital, Goethe University, 60590, Frankfurt, Germany
| | - Jörg Licher
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Ulla Ramm
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Janett Köhn
- Department of Radiation Oncology, University Hospital, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany
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Ramirez-Fort MK, Kardoust-Parizi M, Flannigan R, Bach P, Koch N, Gilman C, Suarez P, Fort DV, McClelland S, Lange CS, Mulhall JP, Fort M, Schlegel PN. Preservation of male fertility in patients undergoing pelvic irradiation. Rep Pract Oncol Radiother 2024; 28:835-845. [PMID: 38515820 PMCID: PMC10954274 DOI: 10.5603/rpor.98731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 12/04/2023] [Indexed: 03/23/2024] Open
Abstract
As the number of cancer survivors increases, so does the demand for preserving male fertility after radiation. It is important for healthcare providers to understand the pathophysiology of radiation-induced testicular injury, the techniques of fertility preservation both before and during radiation, and their role in counseling patients on the risks to their fertility and the means of mitigating these risks. Impaired spermatogenesis is a known testicular toxicity of radiation in both the acute and the late settings, as rapidly dividing spermatogonial germ cells are exquisitely sensitive to irradiation. The threshold for spermatogonial injury and subsequent impairment in spermatogenesis is ~ 0.1 Gy and the severity of gonadal injury is highly dose-dependent. Total doses < 4 Gy may allow for recovery of spermatogenesis and fertility potential, but with larger doses, recovery may be protracted or impossible. All patients undergoing gonadotoxic radiation therapy should be counseled on the possibility of future infertility, offered the opportunity for semen cryopreservation, and offered referral to a fertility specialist. In addition to this, every effort should be made to shield the testes (if not expected to contain tumor) during therapy.
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Affiliation(s)
- Marigdalia K. Ramirez-Fort
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
- Department of Urology, Weill Cornell Medicine, New York, NY, United States
| | - Mehdi Kardoust-Parizi
- Department of Urology, Medical University of Vienna, Vienna, Austria
- Department of Urology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ryan Flannigan
- Department of Urology, Weill Cornell Medicine, New York, NY, United States
| | - Phil Bach
- Department of Urology, Weill Cornell Medicine, New York, NY, United States
| | - Nicholas Koch
- Department of Medical Physics, CONE Health, Greensboro, NC, United States
| | - Casey Gilman
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
- Department of Psychiatry, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Paula Suarez
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
- Department of Psychiatry, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Digna V. Fort
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
| | - Shearwood McClelland
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Christopher S. Lange
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
- Department of Radiation Oncology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - John P. Mulhall
- Department of Sexual and Reproductive Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Migdalia Fort
- Life Sciences & BioDefense, BioFort Corp, Guaynabo, Puerto Rico, United States
| | - Peter N. Schlegel
- Department of Urology, Weill Cornell Medicine, New York, NY, United States
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Khilafath HRAS, Ganesan B, Sekar N, Mohapatra D, Vellingiri J, Prakasarao A, Mahadevan P, Singaravelu G. Comparison and estimation of photoneutron dose produce between 10 MV flattened and unflattened beam in Elekta Versa HD™ medical linac. J Cancer Res Ther 2023; 19:1899-1907. [PMID: 38376295 DOI: 10.4103/jcrt.jcrt_1465_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 04/01/2022] [Indexed: 02/21/2024]
Abstract
BACKGROUND In a high-energy medical linear accelerator (linac), if the interaction of photon energy is higher than the neutron binding energy of high atomic material, it emits a neutron field through photonuclear (γ, n) reaction. AIM The current study, evaluates the photoneutron dose equivalent (PNDE) produced between the 10 MV flattened and unflattened beams as a function of field sizes in the Elekta Versa HD™ linac. MATERIALS AND METHODS The PNDE produced from Versa linac was recorded along the patient plane using the bubble detector personal neutron dosimeter and from the measured PNDE values, the theoretical PNDE values were simulated for various field sizes using nonlinear least-squares curve-fitting as a function of a polynomial. The percentage of deviation (PoD) and Chi-square (χ2) tests were performed between the measured and simulated PNDE values to study the reliability and validity. RESULTS The results show that the mean PoD between the measured and simulated PNDE values for respective positions of a field size of FF beam was found to be -1.99% for 0.3×0.3, -4.39% for 5×5, -3.868% for 10×10, 0.590% for 15×15, 9.18% for 20×20, -4.133% for 25×25, and 0.467% for 30×30 cm2. Similarly, the mean PoD between the measured and simulated PNDE values for flattening filter-free (FFF) beam was found to be 1.36% for 0.3×0.3, -1.39% for 5×5, -5.38% for 10×10, 4.41% for 15×15, 3.84% for 20×20, 5.69% for 25×25, and -1.75% for 30×30 cm2. The maximum deviation between the measured and simulated PNDE values lies within the range ± 5%. CONCLUSIONS From the study, it is observed that the FFF beam produces lesser neutron contamination than the FF beam.
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Affiliation(s)
| | - Bharanidharan Ganesan
- Department of Medical Physics, College of Engineering, Anna University, Chennai, Tamil Nadu, India
| | - Nandakumar Sekar
- Department of Medical Physics, College of Engineering, Anna University, Chennai, Tamil Nadu, India
| | - Dinakrushna Mohapatra
- Department of Medical Physics, College of Engineering, Anna University, Chennai, Tamil Nadu, India
| | | | - Aruna Prakasarao
- Department of Medical Physics, College of Engineering, Anna University, Chennai, Tamil Nadu, India
| | - Pramod Mahadevan
- Department of Radiation Oncology, VPS Lakeshore Hospital, Kochi, Kerala, India
| | - Ganesan Singaravelu
- Department of Medical Physics, College of Engineering, Anna University, Chennai, Tamil Nadu, India
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Saroj DK, Yadav S, Paliwal N, Haldar S, Jagtap A, Kumar A. Assessment of Treatment Plan Quality between Flattening Filter and Flattening Filter Free Photon Beam for Carcinoma of the Esophagus with IMRT Technique. J Biomed Phys Eng 2023; 13:227-238. [PMID: 37312893 PMCID: PMC10258210 DOI: 10.31661/jbpe.v0i0.2108-1381] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/17/2022] [Indexed: 06/15/2023]
Abstract
Background As compared to the flattened photon beam, removing the flattening filter (FF) from the head of a gantry decreases the average energy of the photon beam and increases the dose rate, leading to an impact on the quality of treatment plans. Objective This study aimed to compare the quality of intensity-modulated radiation therapy (IMRT) treatment plans for esophageal cancer with and without a flattened filter photon beam. Material and Methods In this analytical study, 12 patients, who had already been treated with a 6X FF photon beam, were treated based on new IMRT methods using a 6X the flattening filter-free (FFF) photon beam. Both 6X FF IMRT and 6X FFF IMRT plans used identical beam parameters and planning objectives. All plans were evaluated with planning indices and doses for organs at risk (OARs). Results Insignificant dose variation was for HI, CI, D98%, and V95% between FF and FFF photon beam IMRT plans. FF-based IMRT plan delivered a 15.51 % and 11.27% higher mean dose to both lungs and heart than the FFF plan, respectively. The integral dose (ID) for the heart and lungs was 11.21% and 15.51%, respectively, less in the IMRT plan with an FFF photon beam. Conclusion In contrast to the FF photon beam, a filtered photon beam-oriented IMRT plan provides significant OAR sparing without losing the quality of the treatment plan. High monitor units (MUs), low ID, and Beam on Time (BOT) are major highlights of the IMRT plan with FFF beam.
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Affiliation(s)
- Dinesh Kumar Saroj
- Department of Radiotherapy, Alexis Multispecialty Hospital Nagpur-440030 (Maharashtra), India
- Department of Science, Rabindranath Tagore University, Bhopal, Madhya Pradesh, India
| | - Suresh Yadav
- Department of Radiotherapy, Gandhi Medical College, Bhopal-462001 (M.P.), India
| | - Neetu Paliwal
- Department of Science, Rabindranath Tagore University, Bhopal, Madhya Pradesh, India
| | - Subhas Haldar
- Department of Radiotherapy, Saroj Gupta Cancer Center and Research Institute, Kolkata-700063 (West Bengal), India
| | - Amol Jagtap
- Department of Radiotherapy, Alexis Multispecialty Hospital Nagpur-440030 (Maharashtra), India
| | - Arvind Kumar
- Department of Radiation Oncology, All India Institute of Medical Sciences (AIIMS), Rishikesh-249203 (U.K.), India
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Wu J, Song H, Li J, Tang B, Wu F. Evaluation of flattening-filter-free and flattening filter dosimetric and radiobiological criteria for lung SBRT: A volume-based analysis. Front Oncol 2023; 13:1108142. [PMID: 36761961 PMCID: PMC9903338 DOI: 10.3389/fonc.2023.1108142] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/06/2023] [Indexed: 01/26/2023] Open
Abstract
Introduction The use of volumetric modulated arc therapy (VMAT) with flattening-filter-free (FFF) beams is becoming more prevalent in lung cancer stereotactic body radiotherapy (SBRT). The aim in this study was to assess the impact of dosimetric and radiobiological differences between FFF and flattening filter (FF) beams for lung SBRT based on the target volume. Methods A total of 198 lung stereotactic body radiation therapy treatment plans with FFF beams and FF beams were retrospectively selected for this study. For all plans, the prescribed dose was 50 Gy/5 fractions, and the dose volume histogram (DVH) for the target and organs at risk (OAR) and the normal tissue complication probability (NTCP) of the lung were recorded and compared. Moreover, monitor units (MUs), the beam on-time and the treatment time were evaluated. Results The study was performed following the Radiation Therapy Oncology Group (RTOG) 0813 and 0915 protocols. No significant differences in D90, coverage rate (CR) or conformity index (CI) of the target were observed between FFF beams and FF beams (p>0.05). The D2, R50% and gradient index (GI) for the target improved with FFF beams compared with FF beams (p<0.05). FFF beams also significantly reduced the dose for the lung, heart, spinal cord, esophagus and NTCP of the lung (p<0.05), compared with FF beams. However, there was no significant difference in sparing of the trachea (p>0.05). The mean MUs, beam on-time and treatment time were 1871 ± 278 MUs, 3.2 ± 0.2 min and 3.9 ± 0.3 min for FFF beams, and 1890 ± 260 MUs, 4.2 ± 0.3 min and 4.8 ± 0.4 min for FF beams, respectively. Discussion The FFF beam technique for lung SBRT with VMAT results in a better dose fall-off, better dose-sparing of OAR, lower NTCP of the lung and a shorter beam on-time compared with the FF beam technique. Additionally, the improvement in target and OAR-sparing for FFF beams was increased with increasing target volume.
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Affiliation(s)
- Junxiang Wu
- Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Hongchang Song
- Department of Oncology, Xichang People’s Hospital, Xichang, China
| | - Jie Li
- Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bin Tang
- Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Fan Wu
- Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,*Correspondence: Fan Wu,
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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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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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Matuszak N, Kruszyna-Mochalska M, Skrobala A, Ryczkowski A, Romanski P, Piotrowski I, Kulcenty K, Suchorska WM, Malicki J. Nontarget and Out-of-Field Doses from Electron Beam Radiotherapy. Life (Basel) 2022; 12:858. [PMID: 35743890 PMCID: PMC9225003 DOI: 10.3390/life12060858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023] Open
Abstract
In clinical radiotherapy, the most important aspects are the dose distribution in the target volume and healthy organs, including out-of-field doses in the body. Compared to photon beam radiation, dose distribution in electron beam radiotherapy has received much less attention, mainly due to the limited range of electrons in tissues. However, given the growing use of electron intraoperative radiotherapy and FLASH, further study is needed. Therefore, in this study, we determined out-of-field doses from an electron beam in a phantom model using two dosimetric detectors (diode E and cylindrical Farmer-type ionizing chamber) for electron energies of 6 MeV, 9 MeV and 12 MeV. We found a clear decrease in out-of-field doses as the distance from the field edge and depth increased. The out-of-field doses measured with the diode E were lower than those measured with the Farmer-type ionization chamber at each depth and for each electron energy level. The out-of-field doses increased when higher energy megavoltage electron beams were used (except for 9 MeV). The out-of-field doses at shallow depths (1 or 2 cm) declined rapidly up to a distance of 3 cm from the field edge. This study provides valuable data on the deposition of radiation energy from electron beams outside the irradiation field.
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Affiliation(s)
- Natalia Matuszak
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Marta Kruszyna-Mochalska
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland; (A.R.); (P.R.)
| | - Agnieszka Skrobala
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland; (A.R.); (P.R.)
| | - Adam Ryczkowski
- Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland; (A.R.); (P.R.)
| | - Piotr Romanski
- Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland; (A.R.); (P.R.)
| | - Igor Piotrowski
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Katarzyna Kulcenty
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Wiktoria Maria Suchorska
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Julian Malicki
- Department of Electroradiology, Poznan University of Medical Sciences, 61-866 Poznan, Poland; (M.K.-M.); (A.S.); (I.P.); (W.M.S.); (J.M.)
- Department of Medical Physics, Greater Poland Cancer Centre, 61-866 Poznan, Poland; (A.R.); (P.R.)
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Cellular Damage in the Target and Out-Of-Field Peripheral Organs during VMAT SBRT Prostate Radiotherapy: An In Vitro Phantom-Based Study. Cancers (Basel) 2022; 14:cancers14112712. [PMID: 35681692 PMCID: PMC9179488 DOI: 10.3390/cancers14112712] [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: 03/25/2022] [Revised: 05/18/2022] [Accepted: 05/27/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary New developments show that patients with prostate cancer can benefit from radiotherapy delivered with a hypo-fractionated regimen. The aim of our study was to investigate the effect of hypo-fractionated stereotactic body radiation therapy (SBRT) of prostate cancer on out-of-field organs. We used a humanoid phantom to irradiate prostate cells in conditions similar to patient therapy, using SBRT planning. Our results show that radiation doses in the location of the intestine and lung resulted in significantly higher radiation doses than the further locations. We observed a high radiotoxic effect in the cells irradiated in the prostate, and a small increase in DNA damage and cell killing in the intestine location. Gene expression analysis revealed significant enrichment of the biological processes related to the radiation response in the prostate. In the lung and thyroid, the enrichment of several gene groups was revealed, however the processes were not clearly related to the response to radiation. Our study provides extensive data on out-of-field safety of prostate SBRT. Abstract Hypo-fractionated stereotactic body radiation therapy (SBRT) is an effective treatment for prostate cancer (PCa). Although many studies have investigated the effects of SBRT on the prostate and adjacent organs, little is known about the effects further out-of-field. The aim of this study was to investigate, both in vitro and in a quasi-humanoid phantom, the biological effects (using a dose-scaling approach) of radiation in the out-of-field peripheral organs delivered by 6 MV volumetric modulated arc therapy (VMAT) SBRT in a prostate cancer model. Healthy prostate cells were irradiated in a phantom at locations corresponding to the prostate, intestine, lung, thyroid, and brain. Seven 10 Gy fractions of VMAT SBRT were delivered to the target in a single session without intermission (scaled-up method). Radiochromic films were used to measure the doses. The radiobiological response was assessed by measuring DNA breaks, the cell survival fraction, and differences in gene expression profile. Our results showed a strong, multiparametric radiobiological response of the cells in the prostate. Outside of the radiation field, the highest doses were observed in the intestine and lung. A small increase (not statistically significant) in DNA damage and cell death was observed in the intestines. Several gene groups (cell cycle, DNA replication) were depleted in the lung and thyroid (DNA replication, endocytosis), but further analysis revealed no changes in the relevant biological processes. This study provides extensive evidence of the types and extent of radiobiological responses during VMAT SBRT in a prostate cancer model. Additional research is needed to determine whether the radiobiological effects observed in the peripheral organs are validated in a clinical context.
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11
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Influence of Specific Treatment Parameters on Nontarget and Out-of-Field Doses in a Phantom Model of Prostate SBRT with CyberKnife and TrueBeam. Life (Basel) 2022; 12:life12050628. [PMID: 35629296 PMCID: PMC9146748 DOI: 10.3390/life12050628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 11/30/2022] Open
Abstract
The aim of the study was to determine the influence of a key treatment plan and beam parameters on overall dose distribution and on doses in organs laying in further distance from the target during prostate SBRT. Multiple representative treatment plans (n = 12) for TrueBeam and CyberKnife were prepared and evaluated. Nontarget doses were measured with anionization chamber, in a quasi-humanoid phantom at four sites corresponding to the intestines, right lung, thyroid, and head. The following parameters were modified: radiotherapy technique, presence or not of a flattening filter, degree of modulation, and use or not of jaw tracking function for TrueBeam and beam orientation set-up, optimization techniques, and number of MUs for CyberKnife. After usual optimization doses in intestines (near the target) were 0.73% and 0.76%, in head (farthest from target) 0.05% and 0.19% for TrueBeam and CyberKnife, respectively. For TrueBeam the highest peripheral (head, thyroid, lung) doses occurred for the VMAT with the flattening filter while the lowest for 3DCRT. For CyberKnife the highest doses were for gantry with caudal direction beams blocked (gantry close to OARs) while the lowest was the low modulated VOLO optimization technique. The easiest method to reduce peripheral doses was to combine FFF with jaw tracking and reducing monitor units at TrueBeam and to avoid gantry position close to OARs together with reduction of monitor units at CyberKnife, respectively. The presented strategies allowed to significantly reduce out-of-field and nontarget doses during prostate radiotherapy delivered with TrueBeam and CyberKnife. A different approach was required to reduce peripheral doses because of the difference in dose delivery techniques: non-coplanar using CyberKnife and coplanar using TrueBeam, respectively.
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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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Out-of-field organ doses and associated risk of cancer development following radiation therapy with photons. Phys Med 2021; 90:73-82. [PMID: 34563834 DOI: 10.1016/j.ejmp.2021.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/06/2021] [Accepted: 09/13/2021] [Indexed: 11/21/2022] Open
Abstract
Innovations in cancer treatment have contributed to the improved survival rate of these patients. Radiotherapy is one of the main options for cancer management nowadays. High doses of ionizing radiation are usually delivered to the tumor site with high energy photon beams. However, the therapeutic radiation exposure may lead to second cancer induction. Moreover, the introduction of intensity-modulated radiation therapy over the last decades has increased the radiation dose to out-of-field organs compared to that from conventional irradiation. The increased organ doses might result in elevated probabilities for developing secondary malignancies to critical organs outside the treatment volume. The organ-specific dosimetry is considered necessary for the theoretical second cancer risk assessment and the proper analysis of data derived from epidemiological reports. This study reviews the methods employed for the measurement and calculation of out-of-field organ doses from exposure to photons and/or neutrons. The strengths and weaknesses of these dosimetric approaches are described in detail. This is followed by a review of the epidemiological data associated with out-of-field cancer risks. Previously published theoretical cancer risk estimates for adult and pediatric patients undergoing radiotherapy with conventional and advanced techniques are presented. The methodology for the theoretical prediction of the probability of carcinogenesis to out-of-field sites and the limitations of this approach are discussed. The article also focuses on the factors affecting the magnitude of the probability for developing radiotherapy-induced malignancies. The restriction of out-of-field doses and risks through the use of different types of shielding equipment is presented.
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López-Guadalupe VM, Rodríguez-Laguna A, Poitevin-Chacón MA, López-Pineda E, Brandan ME. Out-of-field mean photon energy and dose from 6 MV and 6 MV FFF beams measured with TLD-300 and TLD-100 dosimeters. Med Phys 2021; 48:6567-6577. [PMID: 34528262 DOI: 10.1002/mp.15233] [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: 03/01/2021] [Revised: 09/01/2021] [Accepted: 09/04/2021] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To measure the out-of-field mean photon energy and dose imparted by the secondary radiation field generated by 6 MV and 6 MV FFF beams using TLD-300 and TLD-100 dosimeters and to use the technique to quantify the contributions from the different sources that generate out-of-field radiation. METHODS The mean photon energy and the dose were measured using the TLD-300 glow curve properties and the TLD-100 response, respectively. The TLD-300 glow curve shape was energy-calibrated with gamma rays from 99m Tc, 18 F, 137 Cs, and 60 Co sources, and its energy dependence was quantified by a parameter obtained from the curve deconvolution. The TLD-100 signal was calibrated in absorbed dose-to-water inside the primary field. Dosimeters were placed on the linac head, and on the surface and at 4.5 cm depth in PMMA at 1-15 cm lateral distances from a 10 × 10 cm2 field edge at the isocenter plane. Three configurations of dosimeters around the linac were defined to identify and quantify the contributions from the different sources of out-of-field radiation. RESULTS Typical energies of head leakage were about 500 keV for both beams. The mean energy of collimator-scattered radiation was equal to or larger than 1250 keV and, for phantom-scattered radiation, mean photon energies were 400 keV for the 6 MV and 300 keV for the 6 MV FFF beam. Relative uncertainties to determine mean photon energy were better than 15% for energies below 700 keV, and 40% above 1000 keV. The technique lost its sensitivity to the incident photon energy above 1250 keV. On the phantom surface and at 1-15 cm from the field edge, 80%-90% of out-of-field dose came from scattering in the secondary collimator. At 4.5 cm deep in the phantom and 1-5 cm from the field edge, 50%-60% of the out-of-field dose originated in the phantom. At the points of measurement, the head leakage imparted less than 0.1% of the dose at the isocenter. The 6 MV FFF beam imparted 8-36% less out-of-field dose than the 6 MV beam. These energy results are consistent with general Monte Carlo simulation predictions and show excellent agreement with simulations for a similar linac. The measured out-of-field doses showed good agreement with independent evaluations. CONCLUSIONS The out-of-field mean photon energy and dose imparted by the secondary radiation field were quantified by the applied TLD-300/TLD-100 method. The main sources of out-of-field dose were identified and quantified using three configurations of dosimeters around the linac. This technique could be of value to validate Monte Carlo simulations where the linac head design, configuration, or material composition are unavailable.
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Affiliation(s)
| | | | | | - Eduardo López-Pineda
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - María-Ester Brandan
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Park H, Paganetti H, Schuemann J, Jia X, Min CH. Monte Carlo methods for device simulations in radiation therapy. Phys Med Biol 2021; 66:10.1088/1361-6560/ac1d1f. [PMID: 34384063 PMCID: PMC8996747 DOI: 10.1088/1361-6560/ac1d1f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/12/2021] [Indexed: 11/12/2022]
Abstract
Monte Carlo (MC) simulations play an important role in radiotherapy, especially as a method to evaluate physical properties that are either impossible or difficult to measure. For example, MC simulations (MCSs) are used to aid in the design of radiotherapy devices or to understand their properties. The aim of this article is to review the MC method for device simulations in radiation therapy. After a brief history of the MC method and popular codes in medical physics, we review applications of the MC method to model treatment heads for neutral and charged particle radiation therapy as well as specific in-room devices for imaging and therapy purposes. We conclude by discussing the impact that MCSs had in this field and the role of MC in future device design.
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Affiliation(s)
- Hyojun Park
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Xun Jia
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75235, United States of America
| | - Chul Hee Min
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Republic of Korea
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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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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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Zhang Y, Yan S, Cui Z, Wang Y, Li Z, Yin Y, Li B, Quan H, Zhu J. Out-of-field dose assessment for a 1.5 T MR-Linac with optically stimulated luminescence dosimeters. Med Phys 2021; 48:4027-4037. [PMID: 33714229 PMCID: PMC8360091 DOI: 10.1002/mp.14839] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/04/2021] [Accepted: 03/04/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To assess the out-of-field surface and internal dose of the 1.5 T MR-Linac compared to the conventional external beam linac using optically stimulated luminescence dosimeters (OSLDs), and evaluate the out-of-field dose calculation accuracy of the Monaco treatment planning system (TPS) of the 1.5T MR-Linac. METHODS A cubic solid water phantom, with OSLDs on the surface, was vertically irradiated by MR-Linac square fields with different sizes. In addition, OSLDs were arranged out of the beam edges in four directions. An anthropomorphic adult phantom, with 125 cm3 simulated volume, was irradiated in four orthogonal directions by both MR-Linac and conventional linac at the head, thoracic, and pelvic sites. Out-of-field doses were measured by OSLDs on both the surface and internal emulational organs at risk (OARs). The results were compared to the simulated dose from Monaco TPS. RESULTS At different field sizes (5 × 5 to 20 × 20 cm2 ) and distances (1 to 10 cm) to beam edge, the out-of-field surface dose measured on MR-Linac varied from 0.16 % (10 cm to 5 × 5 cm2 edge) to 7.02 % (1 cm to 20 × 20 cm2 edge) of the maximum dose laterally and from 0.14 % (10 cm to 5 × 5 cm2 edge) to 8.56 % (1 cm to 20 × 20 cm2 edge) of the maximum dose longitudinally. Compared to the OSLDs measured data, the Monaco TPS presented an overestimate of the out-of-field dose of OARs at 0-2 % isodose area on both surface and internal check points, and the overestimation gets greater as the distance increases. The underestimation was found to be 0-35% at 2-5% isodose area on both surface and internal check points. Compared to the conventional linac, MR-Linac delivered higher average values of out-of-field dose on surface check points (20%, 19%, 21%) and internal simulated OARs (42%, 37%, 9%) of the anthropomorphic phantom at head, thoracic, and pelvic irradiations, respectively. CONCLUSIONS Compared to the conventional linac, MR-Linac has the same out-of-field dose distribution. However, considering the absolute dose values, MR-Linac delivered relatively higher out-of-field doses on both surface and internal OARs. Additional radiation shielding to patients undergoing MR-Linac may provide protection from out-of-field exposure.
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Affiliation(s)
- Yan Zhang
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China.,Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Shaojie Yan
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,School of Nuclear Science and Technology, University of South China, Hengyang, P.R. China
| | - Zhen Cui
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yungang Wang
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Zhenjiang Li
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yong Yin
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Baosheng Li
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Hong Quan
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China
| | - Jian Zhu
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,Shandong Medical Imaging and Radiotherapy Engineering Center, Jinan, P.R. China.,Shandong Key Laboratory of Digital Medicine and Computer Assisted Surgery, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China
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Treutwein M, Loeschel R, Hipp M, Koelbl O, Dobler B. Secondary malignancy risk for patients with localized prostate cancer after intensity-modulated radiotherapy with and without flattening filter. J Appl Clin Med Phys 2020; 21:197-205. [PMID: 33147377 PMCID: PMC7769399 DOI: 10.1002/acm2.13088] [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: 07/26/2020] [Revised: 09/16/2020] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
Men treated for localized prostate cancer by radiotherapy have often a remaining life span of 10 yr or more. Therefore, the risk for secondary malignancies should be taken into account. Plans for ten patients were evaluated which had been performed on an Oncentra® treatment planning system for a treatment with an Elekta Synergy™ linac with Agility™ head. The investigated techniques involved IMRT and VMTA with and without flattening filter. Different dose response models were applied for secondary carcinoma and sarcoma risk in the treated region and also in the periphery. As organs at risk we regarded for carcinoma risk urinary bladder, rectum, colon, esophagus, thyroid, and for sarcoma risk bone and soft tissue. The excess absolute risk (EAR) was found very similar in the treated region for both techniques (IMRT and VMAT) and also for both with and without flattening filter. The secondary sarcoma risk resulted about one magnitude smaller than the secondary carcinoma risk. The EAR to the peripheral organs was statistically significant reduced by application of the flattening filter free mode concerning the flattening filter as main source of scattered dose. Application of flattening filter free mode can thus support to reduce second malignancy risk for patients with localized prostate cancer.
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Affiliation(s)
- Marius Treutwein
- Department for radiotherapy, Regensburg University Medical Center, Regensburg, Germany
| | - Rainer Loeschel
- Faculty of computer science and mathematics, Ostbayerische Technische Hochschule, Regensburg, Germany
| | - Matthias Hipp
- Department for radiotherapy, Regensburg University Medical Center, Regensburg, Germany.,Strahlentherapie, Klinikum St. Marien, Amberg, Germany
| | - Oliver Koelbl
- Department for radiotherapy, Regensburg University Medical Center, Regensburg, Germany
| | - Barbara Dobler
- Department for radiotherapy, Regensburg University Medical Center, Regensburg, Germany
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Haciislamoglu E, Gungor G, Aydin G, Canyilmaz E, Guler OC, Zengin AY, Yenice KM. Estimation of secondary cancer risk after radiotherapy in high-risk prostate cancer patients with pelvic irradiation. J Appl Clin Med Phys 2020; 21:82-89. [PMID: 32671989 PMCID: PMC7497909 DOI: 10.1002/acm2.12972] [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: 02/06/2020] [Revised: 05/13/2020] [Accepted: 06/22/2020] [Indexed: 12/21/2022] Open
Abstract
We aimed to estimate the risk of secondary cancer after radiotherapy (RT) in high‐risk prostate cancer (HRPC) patients with pelvic irradiation. Computed tomography data of five biopsy‐proven HRPC patients were selected for this study. Two different planning target volumes (PTV1 and PTV2) were contoured for each patient. The PTV1 included the prostate, seminal vesicles, and pelvic lymphatics, while the PTV2 included only the prostate and seminal vesicles. The prescribed dose was 54 Gy for the PTV1 with a sequential boost (24 Gy for the PTV2). Intensity‐modulated RT (IMRT) and volumetric modulated arc therapy (VMAT) techniques were used to generate treatment plans with 6 and 10 MV photon energies with the flattening filter (FF) or flattening filter‐free (FFF) irradiation mode. The excess absolute risks (EARs) were calculated and compared for the bladder, rectum, pelvic bone, and soft tissue based on the linear‐exponential, plateau, full mechanistic, and specific mechanistic sarcoma dose‐response model. According to the models, all treatment plans resulted in similar risks of secondary bladder or rectal cancer and pelvic bone or soft tissue sarcoma except for the estimated risk of the bladder according to the full mechanistic model using IMRT(6MV;FF) technique compared with VMAT techniques with FFF options. The overall estimation of EAR indicated that the radiation‐induced cancer risk due to RT in HRPC was lower for bladder than the rectum. EAR values ranged from 1.47 to 5.82 for bladder and 6.36 to 7.94 for rectum, depending on the dose–response models used. The absolute risks of the secondary pelvic bone and soft tissue sarcoma were small for the plans examined. We theoretically predicted the radiation‐induced secondary cancer risk in HRPC patients with pelvic irradiation. Nevertheless, prospective clinical trials, with larger patient cohorts with a long‐term follow‐up, are needed to validate these model predictions.
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Affiliation(s)
- Emel Haciislamoglu
- Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
| | - Gorkem Gungor
- Department of Radiation Oncology, Acibadem University, Istanbul, Turkey
| | - Gokhan Aydin
- Department of Radiation Oncology, Acibadem University, Istanbul, Turkey
| | - Emine Canyilmaz
- Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
| | - Ozan Cem Guler
- Department of Radiation Oncology, Faculty of Medicine, Baskent University, Adana, Turkey
| | - Ahmet Yasar Zengin
- Department of Radiation Oncology, Kanuni Research and Education Hospital, Trabzon, Turkey
| | - Kamil Mehmet Yenice
- Department of Radiation and Cellular Oncology, University of Chicago Medicine, Chicago, IL, USA
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García-Hernández T, Vicedo-González A, Sánchez-Nieto B, Romero-Expósito M, Roselló-Ferrando J. PERIPHERAL SURFACE DOSE FROM A LINEAR ACCELERATOR: RADIOCHROMIC FILM EXPERIMENTAL MEASUREMENTS OF FLATTENING FILTER FREE VERSUS FLATTENED BEAMS. RADIATION PROTECTION DOSIMETRY 2020; 188:285-298. [PMID: 31922571 DOI: 10.1093/rpd/ncz286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/06/2019] [Accepted: 11/26/2019] [Indexed: 06/10/2023]
Abstract
There is a growing interest in the use of flattening filter free (FFF) beams due to the shorter treatment times. The reduction of head scatter suggests a better radiation protection to radiotherapy patients, considering the expected decrease in peripheral surface dose (PSD). In this work, PSD of flattened (FF) and FFF-photon beams was compared. A radiochromic film calibration method to reduce energy dependence was used. PSD was measured at distances from 2 to 50 cm to the field border for different square field sizes, modifying relevant clinical parameters. Also, clinical breast and prostate stereotactic body radiotherapy (SBRT) plans were studied. For square beams, FFF PSD is lower compared with FF PSD (differences ranging from 3 to 64%) and 10 MV FFF yields to the lowest value, for distances greater than 5 cm. For SBRT plans, near and far away from the field border, there is a reduction of PSD for FFF-beams, but the behavior at intermediate distances should be checked depending on the case.
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Affiliation(s)
| | - Aurora Vicedo-González
- Departmento de Física Médica, ERESA Hospital General Universitario de Valencia, Valencia, Spain
| | | | | | - Joan Roselló-Ferrando
- Departmento de Física Médica, ERESA Hospital General Universitario de Valencia, Valencia, Spain
- Departamento de Fisiología, Universidad de Valencia, Valencia, Spain
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22
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Comparison of radiotherapy techniques with flattening filter and flattening filter-free in lung radiotherapy according to the treatment volume size. Sci Rep 2020; 10:8983. [PMID: 32488150 PMCID: PMC7265285 DOI: 10.1038/s41598-020-66079-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/13/2020] [Indexed: 11/23/2022] Open
Abstract
In external radiotherapy (RT), the use of flattening filter-free (FFF) radiation beams obtained by removing the flattening filter (FF) in standard linear accelerators is rapidly increasing, and the benefits of clinical use are the issue of research. Advanced treatment techniques have increased the interest in the operation of linear accelerators in FFF mode. The differences of the beams with non-uniform dose distribution created by removing FF compared to the beams with uniform dose distribution used as a standard were examined. These differences were compared in the treatment plans of lung patients who have different planning target volumes (PTV). Clinac IX linear accelerator units were used. Twenty patients with previously completed treatment were divided into two groups depending on the size of the target volume. All patients underwent two different intensity-modulated RT (IMRT) plans using FF and FFF beams. The Wilcoxon Signed-Rank test was used to compare two different techniques (Significance p < 0.05). There was no statistically significant difference between the two techniques when looking at the D2%(Gy), D98%(Gy), D50%(Gy), homogeneity (HI), and conformity index (CI) data for both groups. When the critical organ doses were evaluated, there was a statistically significant difference only in the V20(%) values of the lungs, but these differences were not very large. Monitor unit (MU) data were found to be lower in FF planning, and treatment time was lower in FFF planning. Except for shorter treatment times, and of the lungs V20(%) value, in standard fractionated RT of lung cancer, there was no significant difference between the use of FFF and FF techniques for large and small target volumes.
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A study of dose verification and comparison for complex irradiation field with high dose rate radiation by using a 3D N-isopropylacrylamide gel dosimeter. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06828-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Miften M, Mihailidis D, Kry SF, Reft C, Esquivel C, Farr J, Followill D, Hurkmans C, Liu A, Gayou O, Gossman M, Mahesh M, Popple R, Prisciandaro J, Wilkinson J. Management of radiotherapy patients with implanted cardiac pacemakers and defibrillators: A Report of the AAPM TG-203 †. Med Phys 2019; 46:e757-e788. [PMID: 31571229 DOI: 10.1002/mp.13838] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/16/2019] [Accepted: 08/28/2019] [Indexed: 11/11/2022] Open
Abstract
Managing radiotherapy patients with implanted cardiac devices (implantable cardiac pacemakers and implantable cardioverter-defibrillators) has been a great practical and procedural challenge in radiation oncology practice. Since the publication of the AAPM TG-34 in 1994, large bodies of literature and case reports have been published about different kinds of radiation effects on modern technology implantable cardiac devices and patient management before, during, and after radiotherapy. This task group report provides the framework that analyzes the potential failure modes of these devices and lays out the methodology for patient management in a comprehensive and concise way, in every step of the entire radiotherapy process.
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Affiliation(s)
- Moyed Miften
- Task Group 203, Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Dimitris Mihailidis
- Task Group 203, University of Pennsylvania, Perelman Center for Advanced Medicine, Philadelphia, PA, 19104, USA
| | - Stephen F Kry
- Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Chester Reft
- Department of Radiation Oncology, University of Chicago, Chicago, IL, 60637, USA
| | - Carlos Esquivel
- Department of Radiation Oncology, UT Health Sciences Center, San Antonio, TX, 78229, USA
| | - Jonathan Farr
- Division of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - David Followill
- Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Coen Hurkmans
- Department of Radiotherapy, Catharina Hospital, Eindhoven, the Netherlands
| | - Arthur Liu
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Olivier Gayou
- Department of Radiation Oncology, Allegheny General Hospital, Pittsburg, PA, 15212, USA
| | - Michael Gossman
- Department of Radiation Oncology, Tri-State Regional Cancer Center, Ashland, KY, 41101, USA
| | - Mahadevappa Mahesh
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Richard Popple
- Department of Radiation Oncology, University of Alabama, Birmingham, AL, 35249, USA
| | - Joann Prisciandaro
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA
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A Z, R S, R CEM. Enhancement of the Dose on 12 MV Linac with Free Flattening Filter Mode. J Biomed Phys Eng 2019; 9:437-444. [PMID: 31531296 PMCID: PMC6709350 DOI: 10.31661/jbpe.v0i0.924] [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: 04/10/2018] [Accepted: 05/07/2018] [Indexed: 06/10/2023]
Abstract
PURPOSE In the last years, some studies investigated dosimetric benefits of a free flattening filter for the photon mode in the radiotherapy field. This study aims to provide a theoretical study published and analysis of basic dosimetric properties for a Saturne 43 Linac head to implement free flattening filter beams clinically. MATERIAL AND METHODS This is the first Monte Carlo study for the head of Saturne 43 with replacement flattening filter mode investigating beam dosimetric characteristics, including central axis absorbed doses, beam profiles and photon energy spectra. The later ones were analyzed for flattening filter and replacement flattening filter beams using BEAMnrc and DOSXYZnrc Monte Carlo codes for 10 × 10 cm2, 5 × 5 cm2 and 2 × 2 cm2 square field sizes. RESULTS A 3.94-fold increase of dose rate and electron contaminating increased by 246.4 % with the replacement flattening filter mode for field size of 10 × 10 cm2. Reduction was made by replacement flattening filter beam in the peripheral dose up to 30%, and the time was reduced more than 50 %. CONCLUSION Results obtained from our study revealed that some characteristic dosimetries such as the maximum increase in depth dose rate, decrease in out-of-depth dose, and reducing time can be beneficial for the unflattened beam to be used in the radiotherapy for the advanced techniques.
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Affiliation(s)
- Zeghari A
- Laboratory of Nuclear Physics, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Saaidi R
- Laboratory of Nuclear Physics, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Cherkaoui El Moursli R
- Laboratory of Nuclear Physics, Faculty of Sciences, Mohammed V University, Rabat, Morocco
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Beierholm AR, Nygaard DE, Juhl EL, Hansen R, Hansen J. Evaluating out-of-field doses during radiotherapy of paediatric brain tumours using lead shielding and flattening-filter free beams. Phys Med 2019; 60:1-6. [DOI: 10.1016/j.ejmp.2019.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/06/2019] [Accepted: 03/09/2019] [Indexed: 10/27/2022] Open
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Wijesooriya K. Part I: Out-of-field dose mapping for 6X and 6X-flattening-filter-free beams on the TrueBeam for extended distances. Med Phys 2019; 46:868-876. [PMID: 30589941 DOI: 10.1002/mp.13362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 12/03/2018] [Accepted: 12/17/2018] [Indexed: 01/09/2023] Open
Abstract
PURPOSE With increasing cancer treatment success rates, many patients go on to live long, productive lives following recovery. Therefore, minimizing potential side effects due to dose outside the treated field is becoming a significant consideration in radiation therapy. With many potential treatment configurations available, it is important to quantify how out-of-field dose varies with common variables such as distance from isocenter, couch angle, jaw size, and flattening-filter setting. The accurate quantification of out-of-field dose at extended distances could also benefit researchers and detector developers. While data exist for out-of-field dose from older linear accelerator (Linac) models, the phenomenon has not been described for the latest generation of machines, such as the Varian TrueBeam. The purpose of this study was to comprehensively quantify out-of-field dose for the Varian TrueBeam Linac low energy photons in a wide range of positions and treatment geometries. METHOD AND MATERIALS Out-of-field doses were measured using two phantom setups: (a) A large volume ion chamber with a buildup sleeve to quantify head leakage and collimator scatter background dose; and (b) A farmer ion chamber in solid water to incorporate phantom scatter in addition to collimator scatter, and head leakage background dose. In both cases, the ion chamber was positioned with its length along the slowly varying transverse direction (perpendicular to the radial from isocenter). Doses were measured for four symmetric jaw settings (2 × 2 cm2 , 4 × 4 cm2 , 10 × 10 cm2 , and 20 × 20 cm2 ) for a range of distances from the isocenter (0-100 cm). The angular dependence of the out-of-field dose was measured using four different angles: 0°, 45°, 90°, and 135° with respect to the in-plane direction. All measurements were performed for both 6X and 6X-flattening-filter-free (FFF) beams. RESULTS The lowest out-of-field doses were observed at 60 cm away from isocenter in both in-plane and cross-plane directions for fields smaller than 10 × 10 cm2 . Out-of-field dose decreased with decreasing jaw size (a factor of 4.7 for 6X-FFF and a factor of 3.1 for 6X going from 20 × 20 cm2 to 2 × 2 cm2 at 60 cm from isocenter in the in-plane direction). The 6X-FFF beam produced out-of-field doses as low as 64% of the 6X beam. CONCLUSION This study presents a comprehensive description of 6X and 6X-FFF out-of-field doses on a Varian TrueBeam Linac including measurements at a range of positions, angles, and jaw settings and with and without phantom scatter.
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Affiliation(s)
- Krishni Wijesooriya
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA
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Ben Bouchta Y, Goddard K, Petric MP, Bergman AM. Effects of 10 MV and Flattening-Filter-Free Beams on Peripheral Dose in a Cohort of Pediatric Patients. Int J Radiat Oncol Biol Phys 2018; 102:1560-1568. [DOI: 10.1016/j.ijrobp.2018.07.2002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/18/2018] [Accepted: 07/23/2018] [Indexed: 12/25/2022]
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Chow JCL, Owrangi AM. Mucosal dosimetry on unflattened photon beams: a Monte Carlo phantom study. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aaeaaa] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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30
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Wijesooriya K, Liyanage NK, Kaluarachchi M, Sawkey D. Part II: Verification of the TrueBeam head shielding model in Varian VirtuaLinac via out-of-field doses. Med Phys 2018; 46:877-884. [PMID: 30368838 DOI: 10.1002/mp.13263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 09/17/2018] [Accepted: 10/15/2018] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A good Monte Carlo model with an accurate head shielding model is important in estimating the long-term risks of unwanted radiation exposure during radiation therapy. The aim of this paper was to validate the Monte Carlo simulation of a TrueBeam linear accelerator (linac) head shielding model. We approach this by evaluating the accuracy of out-of-field dose predictions at extended distances which are comprised of scatter from within the patient and treatment head leakage and thus reflect the accuracy of the head shielding model. We quantify the out-of-field dose of a TrueBeam linac for low-energy photons, 6X and 6X-FFF beams, and compare measurements to Monte Carlo simulations using Varian VirtuaLinac that include a realistic head shielding model, for a variety of jaw sizes and angles up to a distance of 100 cm from the isocenter, in both positive and negative directions. Given the high value and utility of the VirtuaLinac model, it is critical that this model is validated thoroughly and the results be available to the medical physics community. MATERIALS AND METHOD Simulations were done using VirtuaLinac, the GEANT4-based Monte Carlo model of the TrueBeam treatment head from Varian Medical Systems, and an in-house GEANT4-based code. VirtuaLinac included a detailed model of the treatment head shielding and was run on the Amazon Web Services cloud to generate spherical phase space files surrounding the treatment head. These phase space files were imported into the in-house code, which modeled the measurement setup with a solid water buildup, the carbon fiber couch, and the gantry stand. For each jaw size (2 × 2 cm2 , 4 × 4 cm2 , 10 × 10 cm2 , and 20 × 20 cm2 ) and angular setting (0°, 90°, 45°, 135°), the dose was calculated at intervals of 5 cm along each measurement direction. RESULTS For the 10 × 10 cm2 jaw size, both 6X and 6X-FFF showed very good agreement between simulation and measurement in both in-plane directions, with no apparent systematic bias. The percentage deviations for these settings were as follows: (mean, STDEV, maximum) (8.34, 6.44, 24.84) for 6X and (13.21, 8.93, 35.56) for 6X-FFF. For all jaw sizes, simulation agreed well in the in-plane direction going away from the gantry, but, some deviations were observed moving toward the gantry at larger distances. At larger distances, for the jaw sizes smaller than 10 × 10 cm2 , the simulation underestimates the dose compared with measurement, while for jaw sizes larger than 10 × 10 cm2 , it overestimates dose. For all comparisons between ±50 cm from isocenter, average absolute agreement between simulation and measurement was better than 28%. CONCLUSION We have validated the Varian VirtuaLinac's head shielding model via out-of-field doses and quantified the differences between TrueBeam head shielding model created out-of-field doses and measurements for an extended distance of 100 cm.
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Affiliation(s)
- Krishni Wijesooriya
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA
| | - Nilanga K Liyanage
- Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA
| | - Maduka Kaluarachchi
- Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA
| | - Daren Sawkey
- Varian Medical Systems, Inc., 3120 Hansen way, Palo Alto, CA, 94304, USA
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Tyler M, Dowdell S. Delivery efficiency and susceptibility to setup uncertainties of flattening filter free lung SBRT: influence of isocentre geometry and treatment modality. Phys Med Biol 2018; 63:205017. [PMID: 30255854 DOI: 10.1088/1361-6560/aae451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Flattening filter free (FFF) photon beams are frequently used in stereotactic body radiation therapy (SBRT) treatments of lung lesions due to favourable dosimetric characteristics and comparable plan quality to conventional flattened beams. For peripheral targets, the treatment isocentre may remain close to the patient midline to minimise collision risks, which we denote as off-axis geometry (OAG). This study used a cohort of ten patients to investigate the sensitivity of OAG SBRT lung plans to offsets in the isocentre position and compared it to those where the isocentre is placed at the centre of the target volume, i.e. central axis geometry (CAG). Comparisons were made for SBRT treatment plans using 3D conformal radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT). No statistically significant difference was found between OAG and CAG for SBRT treatments delivered with either 3DCRT or VMAT techniques in terms of plan quality metrics. Planned monitor units for 3DCRT plans were significantly less (p < 0.001) using CAG compared to OAG for this patient cohort, suggesting more efficient treatment delivery. These significant differences in delivery efficiency based on isocentre geometry were not observed in the VMAT plans. The susceptibility of 3DCRT and VMAT plans to systematic setup uncertainties of 1 mm and 2 mm was not significantly influenced by choice of isocentre geometry. OAG and CAG based treatments are equally robust to systematic uncertainties in isocentre positioning.
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Mishra B, Mishra S, Selvam TP, Chavan ST, Pethe SN. Comparison of Measured and Monte Carlo Calculated Dose Distributions from Indigenously Developed 6 MV Flattening Filter Free Medical Linear Accelerator. J Med Phys 2018; 43:162-167. [PMID: 30305773 PMCID: PMC6172861 DOI: 10.4103/jmp.jmp_58_18] [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] [Indexed: 11/16/2022] Open
Abstract
Purpose: Monte Carlo simulation was carried out for a 6 MV flattening filter-free (FFF) indigenously developed linear accelerator (linac) using the BEAMnrc user-code of the EGSnrc code system. The model was benchmarked against the measurements. A Gaussian distributed electron beam of kinetic energy 6.2 MeV with full-width half maximum of 1 mm was used in this study. Methods: The simulation of indigenously developed linac unit has been carried out by using the Monte Carlo-based BEAMnrc user-code of the EGSnrc code system. Using the simulated model, depth and lateral dose profiles were studied using the DOSXYZnrc user-code. The calculated dose data were compared against the measurements using an RFA dosimertic system made by PTW, Germany (water tank MP3-M and 0.125 cm3 ion chamber). Results: The BEAMDP code was used to analyze photon fluence spectra, mean energy distribution, and electron contamination fluence spectra. Percentage depth dose (PDD) and beam profiles (along both X and Y directions) were calculated for the field sizes 5 cm × 5 cm - 25 cm × 25 cm. The dose difference between the calculated and measured PDD and profile values were under 1%, except for the penumbra region where the maximum deviation was found to be around 3%. Conclusions: A Monte Carlo model of indigenous FFF linac (6 MV) has been developed and benchmarked against the measured data.
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Affiliation(s)
- Bibekananda Mishra
- Radiological Safety Division, Atomic Energy Regulatory Board, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Subhalaxmi Mishra
- Homi Bhabha National Institute, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India.,Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - T Palani Selvam
- Homi Bhabha National Institute, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India.,Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - S T Chavan
- Medical Electronics Division-1, Society for Applied Microwave Electronics Engineering and Research, Mumbai, Maharashtra, India
| | - S N Pethe
- Medical Electronics Division-1, Society for Applied Microwave Electronics Engineering and Research, Mumbai, Maharashtra, India
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Wang L, Ding GX. Estimating the uncertainty of calculated out-of-field organ dose from a commercial treatment planning system. J Appl Clin Med Phys 2018; 19:319-324. [PMID: 29896876 PMCID: PMC6036345 DOI: 10.1002/acm2.12367] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/17/2018] [Accepted: 05/05/2018] [Indexed: 11/09/2022] Open
Abstract
Therapeutic radiation to cancer patients is accompanied by unintended radiation to organs outside the treatment field. It is known that the model-based dose algorithm has limitation in calculating the out-of-field doses. This study evaluated the out-of-field dose calculated by the Varian Eclipse treatment planning system (v.11 with AAA algorithm) in realistic treatment plans with the goal of estimating the uncertainties of calculated organ doses. Photon beam phase-space files for TrueBeam linear accelerator were provided by Varian. These were used as incident sources in EGSnrc Monte Carlo simulations of radiation transport through the downstream jaws and MLC. Dynamic movements of the MLC leaves were fully modeled based on treatment plans using IMRT or VMAT techniques. The Monte Carlo calculated out-of-field doses were then compared with those calculated by Eclipse. The dose comparisons were performed for different beam energies and treatment sites, including head-and-neck, lung, and pelvis. For 6 MV (FF/FFF), 10 MV (FF/FFF), and 15 MV (FF) beams, Eclipse underestimated out-of-field local doses by 30%-50% compared with Monte Carlo calculations when the local dose was <1% of prescribed dose. The accuracy of out-of-field dose calculations using Eclipse is improved when collimator jaws were set at the smallest possible aperture for MLC openings. The Eclipse system consistently underestimates out-of-field dose by a factor of 2 for all beam energies studied at the local dose level of less than 1% of prescribed dose. These findings are useful in providing information on the uncertainties of out-of-field organ doses calculated by Eclipse treatment planning system.
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Affiliation(s)
- Lilie Wang
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - George X Ding
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
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Dosimetric Analysis of Unflattened (FFFB) and Flattened (FB) Photon Beam Energy for Gastric Cancers Using IMRT and VMAT-a Comparative Study. J Gastrointest Cancer 2018. [PMID: 29520733 DOI: 10.1007/s12029-018-0080-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE To evaluate the feasibility of flattening filter free beam (FFFB) for the treatment of gastric tumors and to review their benefits over 6MV flatten beam (6MV_FFB). METHODS Fifteen patients with histologically proven gastric carcinoma were selected. CT scans with slice thickness of 0.3 cm were acquired and planning target volume (PTV) and organ at risk (OAR) were delineated. Plans were made retrospectively for each patient for the prescription dose of 45 Gy/25 fractions to the PTV. Four isocentric plans were compared in the present study on Varian TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, CA, USA). RESULTS PTV D98% was 44.41 ± 0.12, 44.38 ± 0.13, 44.59 ± 0.14, and 44.49 ± 0.19 Gy for IMRT 6MV_FFB, IMRT 6MV_FFFB, VMAT 6MV_FFB, and VMAT 6MV_FFFB respectively. 6MV_FFFB beam minimizes the mean heart dose Dmean (P = 0.001). VMAT dominates over IMRT when it came to kidney doses V12Gy (P = 0.02), V23Gy (P = 0.015), V28Gy (P = 0.011), and Dmax (P < 0.01). VMAT has significantly reduced the doses to kidneys. It was analyzed that 6MV_FFFB significantly reduces the dose to normal tissues (P = 0.006 and P = 0.018). VMAT significantly reduces the TMU, which is required to deliver the similar dose by IMRT (P < 0.01). CONCLUSIONS Unflattened beam spares the organs at risk significantly to avoid the chances of secondary malignancies and reduces the intra-fraction motion during treatment due to provision of higher dose rate. Hence, we conclude that 6MV unflattened beam can be used to treat gastric carcinoma.
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Kimura T, Fukunaga JI, Hirose TA, Hirayama R. [Evaluation of a 2D Diode Array Corresponding to Flattening Filter Free X-ray Beams]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2018; 74:473-479. [PMID: 29780047 DOI: 10.6009/jjrt.2018_jsrt_74.5.473] [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: 06/08/2023]
Abstract
Recently, a medical linear accelerator with a flattening filter free (FFF) mode has led to the use of FFF X-ray beams at clinical sites. The usefulness of FFF X-ray beams in high-precision radiation therapy has been reported. Therefore, the quality assurance and quality control for FFF X-ray beams have become necessary. In this study, the characteristics of the detectors of a newly developed 2-D diode array (MapCHECK2, Sun Nuclear Corporation) for FFF X-ray beams, i.e., dose reproducibility, dose rate dependence, dose linearity, and output factor, were evaluated. For the measurements, 6 and 10 MV FFF beams were used. The results showed that the coefficient of variation for dose reproducibility was within 0.08%, the dose rate dependence was less than 1.0%, the coefficient of determination of dose linearity was found to be R2=1.0, which was high, and the output factor agreed within 2.5% as compared with the farmer ion chamber, diode E, and pinpoint ion chamber for field sizes greater than 2×2 cm2. The results suggested that MapCHECK2 could be a useful tool for quality assurance and quality control for FFF X-ray beams.
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Affiliation(s)
- Tomoko Kimura
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital
| | - Jun-Ichi Fukunaga
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital
| | - Taka-Aki Hirose
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital
| | - Ryota Hirayama
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital
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Lechner W, Kuess P, Georg D, Palmans H. Equivalent (uniform) square field sizes of flattening filter free photon beams. ACTA ACUST UNITED AC 2017; 62:7694-7713. [DOI: 10.1088/1361-6560/aa83f5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Treutwein M, Hipp M, Koelbl O, Dobler B. Volumetric-modulated arc therapy and intensity-modulated radiation therapy treatment planning for prostate cancer with flattened beam and flattening filter free linear accelerators. J Appl Clin Med Phys 2017; 18:307-314. [PMID: 28857432 PMCID: PMC5875831 DOI: 10.1002/acm2.12168] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/17/2017] [Accepted: 07/20/2017] [Indexed: 12/25/2022] Open
Abstract
This study on patients with localized prostate cancer was set up to investigate valuable differences using flattened beam (FB) and flattening filter free (FFF) mode in the application of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT). For ten patients, four different plans were calculated with Oncentra planning system of Elekta, using Synergy machines: IMRT and VMAT, with and without flattening filter. Homogeneity and conformity indexes, dose to the organs at risk, and measurements of peripheral dose and dosimetric plan verification including record of the delivery times were analyzed and statistically evaluated. The indexes for homogeneity and conformity (CTV and PTV) are either advantageous or not significantly different for FFF compared to FB with one minor exception. Regarding the doses to the organs at risk and the measured peripheral dose, equivalent or lower doses were delivered for FFF than with FB. Furthermore, the delivery times were significantly shorter for FFF. VMAT compared to IMRT reveals benefits or at least equivalent values. VMAT-FFF combines the most advantageous plan quality parameters with the shortest delivery times and reduced peripheral dose and is therefore recommended for the given equipment and cancer localization.
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Affiliation(s)
- Marius Treutwein
- Department for Radiotherapy, Regensburg University Medical Center, Regensburg, Germany
| | - Matthias Hipp
- Department for Radiotherapy, Regensburg University Medical Center, Regensburg, Germany.,Klinikum St. Marien, Strahlentherapie, Amberg, Germany
| | - Oliver Koelbl
- Department for Radiotherapy, Regensburg University Medical Center, Regensburg, Germany
| | - Barbara Dobler
- Department for Radiotherapy, Regensburg University Medical Center, Regensburg, Germany
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Kry SF, Bednarz B, Howell RM, Dauer L, Followill D, Klein E, Paganetti H, Wang B, Wuu CS, George Xu X. AAPM TG 158: Measurement and calculation of doses outside the treated volume from external-beam radiation therapy. Med Phys 2017; 44:e391-e429. [DOI: 10.1002/mp.12462] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 05/17/2017] [Accepted: 05/25/2017] [Indexed: 12/14/2022] Open
Affiliation(s)
- Stephen F. Kry
- Department of Radiation Physics; MD Anderson Cancer Center; Houston TX 77054 USA
| | - Bryan Bednarz
- Department of Medical Physics; University of Wisconsin; Madison WI 53705 USA
| | - Rebecca M. Howell
- Department of Radiation Physics; MD Anderson Cancer Center; Houston TX 77054 USA
| | - Larry Dauer
- Departments of Medical Physics/Radiology; Memorial Sloan-Kettering Cancer Center; New York NY 10065 USA
| | - David Followill
- Department of Radiation Physics; MD Anderson Cancer Center; Houston TX 77054 USA
| | - Eric Klein
- Department of Radiation Oncology; Washington University; Saint Louis MO 63110 USA
| | - Harald Paganetti
- Department of Radiation Oncology; Massachusetts General Hospital and Harvard Medical School; Boston MA 02114 USA
| | - Brian Wang
- Department of Radiation Oncology; University of Louisville; Louisville KY 40202 USA
| | - Cheng-Shie Wuu
- Department of Radiation Oncology; Columbia University; New York NY 10032 USA
| | - X. George Xu
- Department of Mechanical, Aerospace, and Nuclear Engineering; Rensselaer Polytechnic Institute; Troy NY 12180 USA
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Renaud M, Serban M, Seuntjens J. On mixed electron–photon radiation therapy optimization using the column generation approach. Med Phys 2017; 44:4287-4298. [DOI: 10.1002/mp.12338] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 05/01/2017] [Accepted: 05/03/2017] [Indexed: 01/02/2023] Open
Affiliation(s)
- Marc‐André Renaud
- Department of Physics & Medical Physics Unit McGill University Montreal Canada
| | - Monica Serban
- Medical Physics Unit McGill University Health Centre Montreal Canada
| | - Jan Seuntjens
- Medical Physics Unit McGill University and Research Institute of the McGill University Health Centre Montreal Canada
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Surface dose measurements in and out of field: Implications for breast radiotherapy with megavoltage photon beams. Z Med Phys 2017; 27:318-323. [PMID: 28595775 DOI: 10.1016/j.zemedi.2017.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 04/30/2017] [Accepted: 05/15/2017] [Indexed: 11/22/2022]
Abstract
This study examines the difference in surface dose between flat and flattening filter free (FFF) photon beams in the context of breast radiotherapy. The surface dose was measured for 6MV, 6MV FFF, 10MV, 10MV FFF and 18MV photon beams using a thin window ionisation chamber for various field sizes. Profiles were acquired to ascertain the change in surface dose off-axis. Out-of-field measurements were included in a clinically representative half beam block tangential breast field. In the field centres of FFF beams the surface dose was found to be increased for small fields and decreased for large fields compared to flat beams. For FFF beams, surface dose was found to decrease off-axis and resulted in lower surface dose out-of-field compared to flat beams.
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41
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Comparison of Flattening Filter (FF) and Flattening-Filter-Free (FFF) 6 MV photon beam characteristics for small field dosimetry using EGSnrc Monte Carlo code. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.02.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Comparison of surface dose delivered by 7 MV-unflattened and 6 MV-flattened photon beams. Rep Pract Oncol Radiother 2017; 22:243-250. [PMID: 28479873 DOI: 10.1016/j.rpor.2016.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 10/07/2016] [Accepted: 12/20/2016] [Indexed: 11/23/2022] Open
Abstract
AIM The purpose of this study is to determine the central-axis dose in the buildup region and the surface dose delivered by a 6 MV flattened photon beam (6 MV-FB) and a higher energy unflattened (7 MV-FFF) therapeutic photon beam for different-sized square fields with open fields and modifying filters. MATERIALS AND METHODS The beams are produced by a Siemens Artiste linear accelerator with a NACP-02 ionization chamber and the dose is measured by using GafChromic film and two different, commonly used, dosimeters: a p-type photon semiconductor dosimeter (PFD) and a cylindrical ionization chamber (CC13). RESULTS The results indicate that the surface dose increases linearly with FS for both open and wedged fields for the 6 MV-FB and 7 MV-FFF beams. The surface dose delivered by the 7 MV-UFB beam is consistent with that delivered by the 6 MV-FB beam for field sizes up to 10 cm × 10 cm, after which the surface dose decreases. The buildup dose for the 7 MV-UFB beam is slightly less than that for the 6 MV-FB beam for field sizes ranging from 5 cm × 5 cm to 15 cm × 15 cm. For both the 6 MV-FB and 7 MV-FFF beams, the measured surface dose clearly increases with increasing field size, regardless of the detector used in the measurement. The surface dose measured with the PFD dosimeter and the NACP-02 and CC13 chambers differ significantly from the results obtained when using GafChromic film. The 7 MV-FFF beam results in a slightly smaller surface dose in the buildup region compared with the 6 MV-FB beam. CONCLUSIONS The surface dose delivered by the higher energy 7 MV-FFF beam is less than that delivered by the energy-unmatched FFF beam in previously published works.
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Covington EL, Ritter TA, Moran JM, Owrangi AM, Prisciandaro JI. Technical Report: Evaluation of peripheral dose for flattening filter free photon beams. Med Phys 2017; 43:4789. [PMID: 27487896 DOI: 10.1118/1.4958963] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop a comprehensive peripheral dose (PD) dataset for the two unflattened beams of nominal energy 6 and 10 MV for use in clinical care. METHODS Measurements were made in a 40 × 120 × 20 cm(3) (width × length × depth) stack of solid water using an ionization chamber at varying depths (dmax, 5, and 10 cm), field sizes (3 × 3 to 30 × 30 cm(2)), and distances from the field edge (5-40 cm). The effects of the multileaf collimator (MLC) and collimator rotation were also evaluated for a 10 × 10 cm(2) field. Using the same phantom geometry, the accuracy of the analytic anisotropic algorithm (AAA) and Acuros dose calculation algorithm was assessed and compared to the measured values. RESULTS The PDs for both the 6 flattening filter free (FFF) and 10 FFF photon beams were found to decrease with increasing distance from the radiation field edge and the decreasing field size. The measured PD was observed to be higher for the 6 FFF than for the 10 FFF for all field sizes and depths. The impact of collimator rotation was not found to be clinically significant when used in conjunction with MLCs. AAA and Acuros algorithms both underestimated the PD with average errors of -13.6% and -7.8%, respectively, for all field sizes and depths at distances of 5 and 10 cm from the field edge, but the average error was found to increase to nearly -69% at greater distances. CONCLUSIONS Given the known inaccuracies of peripheral dose calculations, this comprehensive dataset can be used to estimate the out-of-field dose to regions of interest such as organs at risk, electronic implantable devices, and a fetus. While the impact of collimator rotation was not found to significantly decrease PD when used in conjunction with MLCs, results are expected to be machine model and beam energy dependent. It is not recommended to use a treatment planning system to estimate PD due to the underestimation of the out-of-field dose and the inability to calculate dose at extended distances due to the limits of the dose calculation matrix.
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Affiliation(s)
- E L Covington
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109
| | - T A Ritter
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 and Department of Radiation Oncology, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48105
| | - J M Moran
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109
| | - A M Owrangi
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109
| | - J I Prisciandaro
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109
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Li F, Park JY, Barraclough B, Lu B, Li J, Liu C, Yan G. Efficient independent planar dose calculation for FFF IMRT QA with a bivariate Gaussian source model. J Appl Clin Med Phys 2017; 18:125-135. [PMID: 28300374 PMCID: PMC5689940 DOI: 10.1002/acm2.12056] [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: 08/19/2016] [Revised: 11/07/2016] [Accepted: 01/11/2017] [Indexed: 11/07/2022] Open
Abstract
The aim of this study is to perform a direct comparison of the source model for photon beams with and without flattening filter (FF) and to develop an efficient independent algorithm for planar dose calculation for FF‐free (FFF) intensity‐modulated radiotherapy (IMRT) quality assurance (QA). The source model consisted of a point source modeling the primary photons and extrafocal bivariate Gaussian functions modeling the head scatter, monitor chamber backscatter, and collimator exchange effect. The model parameters were obtained by minimizing the difference between the calculated and measured in‐air output factors (Sc). The fluence of IMRT beams was calculated from the source model using a backprojection and integration method. The off‐axis ratio in FFF beams were modeled with a fourth degree polynomial. An analytical kernel consisting of the sum of three Gaussian functions was used to describe the dose deposition process. A convolution‐based method was used to account for the ionization chamber volume averaging effect when commissioning the algorithm. The algorithm was validated by comparing the calculated planar dose distributions of FFF head‐and‐neck IMRT plans with measurements performed with a 2D diode array. Good agreement between the measured and calculated Sc was achieved for both FF beams (<0.25%) and FFF beams (<0.10%). The relative contribution of the head‐scattered photons reduced by 34.7% for 6 MV and 49.3% for 10 MV due to the removal of the FF. Superior agreement between the calculated and measured dose distribution was also achieved for FFF IMRT. In the gamma comparison with a 2%/2 mm criterion, the average passing rate was 96.2 ± 1.9% for 6 MV FFF and 95.5 ± 2.6% for 10 MV FFF. The efficient independent planar dose calculation algorithm is easy to implement and can be valuable in FFF IMRT QA.
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Affiliation(s)
- Feifei Li
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
| | - Ji-Yeon Park
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
| | - Brendan Barraclough
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
- Department of Biomedical Engineering; University of Florida; Gainesville FL USA
| | - Bo Lu
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
| | - Jonathan Li
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
| | - Chihray Liu
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
| | - Guanghua Yan
- Department of Radiation Oncology; University of Florida; Gainesville FL USA
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Budgell G, Brown K, Cashmore J, Duane S, Frame J, Hardy M, Paynter D, Thomas R. IPEM topical report 1: guidance on implementing flattening filter free (FFF) radiotherapy. Phys Med Biol 2016; 61:8360-8394. [DOI: 10.1088/0031-9155/61/23/8360] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Chung JB, Kang SW, Eom KY, Song C, Choi KS, Suh TS. Comparison of Dosimetric Performance among Commercial Quality Assurance Systems for Verifying Pretreatment Plans of Stereotactic Body Radiotherapy Using Flattening-Filter-Free Beams. J Korean Med Sci 2016; 31:1742-1748. [PMID: 27709851 PMCID: PMC5056205 DOI: 10.3346/jkms.2016.31.11.1742] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to compare the performance of different commercial quality assurance (QA) systems for the pretreatment verification plan of stereotactic body radiotherapy (SBRT) with volumetric arc therapy (VMAT) technique using a flattening-filter-free beam. The verification for 20 pretreatment cancer patients (seven lung, six spine, and seven prostate cancers) were tested using three QA systems (EBT3 film, I'mRT MatriXX array, and MapCHECK). All the SBRT-VMAT plans were optimized in the Eclipse (version 11.0.34) treatment planning system (TPS) using the Acuros XB dose calculation algorithm and were delivered to the Varian TrueBeam® accelerator equipped with a high-definition multileaf collimator. Gamma agreement evaluation was analyzed with the criteria of 2% dose difference and 2 mm distance to agreement (2%/2 mm) or 3%/3 mm. The highest passing rate (99.1% for 3%/3 mm) was observed on the MapCHECK system while the lowest passing rate was obtained on the film. The pretreatment verification results depend on the QA systems, treatment sites, and delivery beam energies. However, the delivery QA results for all QA systems based on the TPS calculation showed a good agreement of more than 90% for both the criteria. It is concluded that the three 2D QA systems have sufficient potential for pretreatment verification of the SBRT-VMAT plan.
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Affiliation(s)
- Jin Beom Chung
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sang Won Kang
- Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Keun Yong Eom
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Changhoon Song
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kyoung Sik Choi
- Department of Radiation Oncology, SAM Anyang Hospital, Anyang, Korea
| | - Tae Suk Suh
- Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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mARC Treatment of Hypopharynx Carcinoma with Flat and Flattening-Filter-Free Beam Energies - A Planning Study. PLoS One 2016; 11:e0164616. [PMID: 27741272 PMCID: PMC5065169 DOI: 10.1371/journal.pone.0164616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 09/22/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The recently implemented mARC-rotation-technique is capable to deliver high dose rate bursts. For the case of hypopharynx cancer plans we evaluate whether the mARC can achieve an advantage in treatment time in comparison to IMRT. These plans consider two arcs with flat and flattening filter free (FFF) beam energies. MATERIALS AND METHODS For 8 hypopharynx-cancer patients step-and-shoot-IMRT and mARC plans were created retrospectively using flat and FFF beam energy. The comparison of the plan scenarios considered measures of quality for PTV coverage and sparing of organs at risk. All plans were irradiated on an anthromorphic phantom equipped with thermoluminescent dosimeters to measure scattered dose and treatment times. RESULTS A visual comparison of the dose distribution did not show a marked preference for either technique or energy. The statistical evaluation yielded significant differences in favor of the mARC technique and the FFF energy. Scattered dose could be decreased markedly by the use of the mARC technique. Treatment times could be reduced up to 3 minutes with the use of mARC in comparison to IMRT. The high dose rate energy results in another time advantage of about 1 minute. CONCLUSIONS All four plan scenarios yielded equally good quality plans. A combination of the mARC technique with FFF 7 MV high dose rate resulted in a decrease of treatment times from about 9 minutes to 5-6 minutes in comparison to 6 MV IMRT.
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Sigamani A, Nambiraj A, Yadav G, Giribabu A, Srinivasan K, Gurusamy V, Raman K, Karunakaran K, Thiyagarajan R. Surface dose measurements and comparison of unflattened and flattened photon beams. J Med Phys 2016; 41:85-91. [PMID: 27217619 PMCID: PMC4871008 DOI: 10.4103/0971-6203.181648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The purpose of this study was to evaluate the central axis dose in the build-up region and the surface dose of a 6 MV and 10 MV flattened photon beam (FB) and flattening filter free (FFF) therapeutic photon beam for different square field sizes (FSs) for a Varian Truebeam linear accelerator using parallel-plate ionization chamber and Gafchromic film. Knowledge of dosimetric characteristics in the build-up region and surface dose of the FFF is essential for clinical care. The dose measurements were also obtained empirically using two different commonly used dosimeters: a p-type photon semiconductor dosimeter and a cylindrical ionization chamber. Surface dose increased linearly with FS for both FB and FFF photon beams. The surface dose values of FFF were higher than the FB FSs. The measured surface dose clearly increases with increasing FS. The FFF beams have a modestly higher surface dose in the build-up region than the FB. The dependence of source to skin distance (SSD) is less significant in FFF beams when compared to the flattened beams at extended SSDs.
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Affiliation(s)
- Ashokkumar Sigamani
- Division of Medical Physics, School of Advanced Sciences, VIT University, New Delhi, India
| | - Arunai Nambiraj
- Division of Medical Physics, School of Advanced Sciences, VIT University, New Delhi, India
| | - Girigesh Yadav
- Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
| | - Ananda Giribabu
- Department of Radiation Oncology, Krishna Institute of Sciences, Hyderabad, Telangana, India
| | | | - Venkadamanickam Gurusamy
- Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
| | - Kothanda Raman
- Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
| | - Kaviarasu Karunakaran
- Division of Medical Physics, School of Advanced Sciences, VIT University, New Delhi, India
| | - Rajesh Thiyagarajan
- Division of Medical Physics, School of Advanced Sciences, VIT University, New Delhi, India
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Yan Y, Yadav P, Bassetti M, Du K, Saenz D, Harari P, Paliwal BR. Dosimetric differences in flattened and flattening filter-free beam treatment plans. J Med Phys 2016; 41:92-9. [PMID: 27217620 PMCID: PMC4871009 DOI: 10.4103/0971-6203.181636] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study investigated the dosimetric differences in treatment plans from flattened and flattening filter-free (FFF) beams from the TrueBeam System. A total of 104 treatment plans with static (sliding window) intensity-modulated radiotherapy beams and volumetric-modulated arc therapy (VMAT) beams were generated for 15 patients involving three cancer sites. In general, the FFF beam provides similar target coverage as the flattened beam with improved dose sparing to organ-at-risk (OAR). Among all three cancer sites, the head and neck showed more important differences between the flattened beam and FFF beam. The maximum reduction of the FFF beam in the mean dose reached up to 2.82 Gy for larynx in head and neck case. Compared to the 6 MV flattened beam, the 10 MV FFF beam provided improved dose sparing to certain OARs, especially for VMAT cases. Thus, 10 MV FFF beam could be used to improve the treatment plan.
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Affiliation(s)
- Yue Yan
- Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA
| | - Poonam Yadav
- Department of Human Oncology, University of Wisconsin, Madison, USA; Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA
| | - Michael Bassetti
- Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA
| | - Kaifang Du
- Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA
| | - Daniel Saenz
- Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA
| | - Paul Harari
- Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA
| | - Bhudatt R Paliwal
- Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA
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Meshram MN, Pramanik S, Ranjith CP, Gopal SK, Dobhal R. Dosimetric properties of equivalent-quality flattening filter-free (FFF) and flattened photon beams of Versa HD linear accelerator. J Appl Clin Med Phys 2016; 17:358-370. [PMID: 27167293 PMCID: PMC5690903 DOI: 10.1120/jacmp.v17i3.6173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/18/2016] [Accepted: 01/12/2016] [Indexed: 11/23/2022] Open
Abstract
This study presents the basic dosimetric properties of photon beams of a Versa HD linear accelerator (linac), which is capable of delivering flattening filter‐free (FFF) beams with a beam quality equivalent to the corresponding flattened beams based on comprehensive beam data measurement. The analyzed data included the PDDs, profiles, penumbra, out‐of‐field doses, surface doses, output factors, head and phantom scatter factors, and MLC transmissions for both FFF and flattened beams of 6 MV and 10 MV energy from an Elekta Versa HD linac. The 6MVFFF and 10MVFFF beams had an equivalent mean energy to the flattened beams and showed less PDD variations with the field sizes. Compared with their corresponding flattened beams, Dmax was deeper for FFF beams for all field sizes; the ionization ratio variations with the field size were lower for FFF beams; the out‐of‐field doses were lower and the penumbras were sharper for the FFF beams; the off‐axis profile variations with the depths were lesser for the FFF beams. Further, the 6MVFFF and 10MVFFF beams had 35.7% and 40.9% less variations in output factor with the field size, respectively. The collimator exchange effect was reduced in the FFF mode. The head scatter factor showed 59.1% and 73.6% less variations, on average, for the 6MVFFF and 10MVFFF beams, respectively; the variations in the phantom scatter factor were also smaller. The surface doses for all beams increased linearly with the field size. The 6MVFFF and 10MVFFF beams had higher surface doses than the corresponding flattened beams for field sizes of up to 10×10cm2 but had lower surface doses for larger fields. Both FFF beams had lower average MLC transmissions than the flattened beams. The finding that the FFF beams were of equivalent quality to the corresponding flattened beams indicates a significant difference from the data on unmatched FFF beams. PACS number(s): 87.56.bd, 87.55.Qr
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