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Walter AE, Cosper PF, Nickel KP, Ramesh S, Khan AU, DeWerd LA, Kimple RJ. Biological Characterization of the Effects of Filtration on the Xoft Axxent® Electronic Brachytherapy Source for Cervical Cancer Applications. Radiat Res 2023; 199:429-438. [PMID: 37014873 PMCID: PMC10288372 DOI: 10.1667/rade-22-00112.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 03/10/2023] [Indexed: 04/05/2023]
Abstract
Low-energy X-ray sources that operate in the kilovoltage energy range have been shown to induce more cellular damage when compared to their megavoltage counterparts. However, low-energy X-ray sources are more susceptible to the effects of filtration on the beam spectrum. This work sought to characterize the biological effects of the Xoft Axxent® source, a low-energy therapeutic X-ray source, both with and without the titanium vaginal applicator in place. It was hypothesized that there would be an increase in relative biological effectiveness (RBE) of the Axxent® source compared to 60Co and that the source in the titanium vaginal applicator (SIA) would have decreased biological effects compared to the bare source (BS). This hypothesis was drawn from linear energy transfer (LET) simulations performed using the TOPAS Monte Carlo user code as well a reduction in dose rate of the SIA compared to the BS. A HeLa cell line was maintained and used to evaluate these effects. Clonogenic survival assays were performed to evaluate differences in the RBE between the BS and SIA using 60Co as the reference beam quality. Neutral comet assay was used to assess induction of DNA strand damage by each beam to estimate differences in RBE. Quantification of mitotic errors was used to evaluate differences in chromosomal instability (CIN) induced by the three beam qualities. The BS was responsible for the greatest quantity of cell death due to a greater number of DNA double strand breaks (DSB) and CIN observed in the cells. The differences observed in the BS and SIA surviving fractions and RBE values were consistent with the 13% difference in LET as well as the factor of 3.5 reduction in dose rate of the SIA. Results from the comet and CIN assays were consistent with these results as well. The use of the titanium applicator results in a reduction in the biological effects observed with these sources, but still provides an advantage over megavoltage beam qualities. © 2023 by Radiation Research Society.
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Affiliation(s)
- Autumn E. Walter
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Pippa F. Cosper
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- University of Wisconsin, Carbone Cancer Center, Madison, WI
| | - Kwangok P. Nickel
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Shrey Ramesh
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Ahtesham U. Khan
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Larry A. DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- University of Wisconsin, Carbone Cancer Center, Madison, WI
| | - Randall J. Kimple
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- University of Wisconsin, Carbone Cancer Center, Madison, WI
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2
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Chin M, Rowshanfarzad P, Neveri G, Ebert MA, Pfefferlé D. Dosimetric evaluation of an intraoperative radiotherapy system: a measurement-based and Monte-Carlo modelling investigation. Phys Eng Sci Med 2023; 46:687-701. [PMID: 36952208 DOI: 10.1007/s13246-023-01243-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 03/09/2023] [Indexed: 03/24/2023]
Abstract
Intraoperative radiotherapy (IORT) is a specialised subset of radiotherapy, where a high radiation dose is delivered to a surgically exposed tumour bed in order to eradicate any remaining cancer cells. The aim of this study was to examine the dose characteristics of the Zeiss Intrabeam IORT device which provides near-isotropic emission of up to 50 kV X-rays. The EGSnrc Monte Carlo (MC) code system was used to simulate the device and percentage depth dose (PDD) data measured with a soft X-ray parallel-plate ionisation chamber were used for model verification. The model provided energy spectra, isodose curves and mean photon energies. In addition, EBT3 Gafchromic film was used to verify the MC model by examining PDDs and 2D dose distributions for various applicators. The differences between MC model and ionisation chamber measurements were within 3% for most points, with a maximum deviation of ~ 9%. Most of the simulated PDD points were within 5% of the film-measured data, with a maximum deviation of ~ 10%. The mean energy of the bare probe was found to be 21.19 keV. The mean photon energy from applicators ranged from 29.00 to 30.85 keV. Results of this study may be useful for future work on creating a system for treatment planning.
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Affiliation(s)
- Marsha Chin
- School of Physics, Mathematics and Computing, University of Western Australia, 35 Stirling Highway, Mailbag M013, CRAWLEY, Perth, WA, 6009, Australia.
| | - Pejman Rowshanfarzad
- School of Physics, Mathematics and Computing, University of Western Australia, 35 Stirling Highway, Mailbag M013, CRAWLEY, Perth, WA, 6009, Australia
| | - Gabor Neveri
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - Martin A Ebert
- School of Physics, Mathematics and Computing, University of Western Australia, 35 Stirling Highway, Mailbag M013, CRAWLEY, Perth, WA, 6009, Australia
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - David Pfefferlé
- School of Physics, Mathematics and Computing, University of Western Australia, 35 Stirling Highway, Mailbag M013, CRAWLEY, Perth, WA, 6009, Australia
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Intraoperative Radiotherapy with Balloon-Based Electronic Brachytherapy System-A Systematic Review and First Bulgarian Experience in Breast Cancer Patients. ACTA ACUST UNITED AC 2021; 28:3932-3944. [PMID: 34677253 PMCID: PMC8534590 DOI: 10.3390/curroncol28050335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 09/21/2021] [Accepted: 09/25/2021] [Indexed: 12/18/2022]
Abstract
(1) Background: We aimed to analyze currently available studies with intraoperative radiotherapy (IORT) as a choice of treatment where the Xoft Axxent® electronic brachytherapy (eBx) system was used as a single-dose irradiation and an exclusive radiotherapy approach at the time of surgery in patients with early breast cancer (EBC). We also compared the results of the systematic review to the Bulgarian experience. (2) Methods and Materials: We performed a systematic review of the studies published before February 2021, which investigate the application of a single-fraction 20 Gy radiation treatment, delivered at the time of lumpectomy in EBC patients with the Xoft Axxent® eBx System. A systematic search in PubMed, Scopus, and ScienceDirect was performed. The results are reported following the PRISMA guidelines. The criteria on patients’ selection for IORT (the additional need for EBRT), cosmetic outcomes, and recurrence rate from the eligible studies are compared to the treatment results in Bulgarian patients. (3) Results: We searched through 1032 results to find 17 eligible studies. There are no published outcomes from randomized trials. When reported, the cosmetic outcomes in most of the studies are defined as excellent. The observed recurrence rate is low (1–5.8%). Still, the number of patients additionally referred to postoperative external breast radiotherapy (EBRT) is up to 31%. Amongst the 20 patients treated in Bulgaria, the cosmetic outcomes are also evaluated as excellent, five of which (25%) are referred for EBRT. Within median follow-up of 39 months, there was one local and one distal recurrence. (4) Conclusions: Current evidence demonstrates the Xoft Axxent® eBx system as a safe and feasible technique for IORT delivery in EBC patients. There are no randomized controlled trials conducted at this time point to prove its long-term effectiveness. Better patient selection and a reimbursement strategy have to be proposed to extend the application of this technique in Bulgaria.
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Robatjazi M, Baghani HR, Rostami A, Pashazadeh A. Monte Carlo-based calculation of nano-scale dose enhancement factor and relative biological effectiveness in using different nanoparticles as a radiosensitizer. Int J Radiat Biol 2021; 97:1289-1298. [PMID: 34047663 DOI: 10.1080/09553002.2021.1934748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Nowadays, some nanoparticles (NPs) are known and used as radiosensitizers in radiotherapy and radiobiology, due to their desired biological, physical, and chemical effects on cells. This study aimed to evaluate and compare the dose enhancement factor (DEF) and the biological effectiveness of some common NPs through EGSnrc and MCDS Monte Carlo (MC) simulation codes. MATERIALS AND METHODS To evaluate considered NPs' DEF, a single NP with 50 nm diameter was simulated at the center of concentric spheres. NP irradiations were done with 30, 60, and 100 keV photon energies. The secondary electron spectra were scored at the surface of considered NPs, and the dose values were scored at surrounding water-filled spherical shells which were distributed up to 4000 nm from the NP surface. The electron spectra were used in the MCDS code to obtain different initial DNA damages for the calculation of enhanced relative biological effectiveness (eRBE). RESULTS By decreasing the photon energy, an increment of DEF was seen for all studied NPs. The maximum DEF at 30, 60, and 100 keV photon energies were respectively related to silver (Ag), gadolinium (Gd), and bismuth (Bi) NPs. The maximum double-strand break (DSB) related (eRBEDSB) values for the 30 keV photon belonged to Ag, while BiNPs showed the maximum values at other photon energies. The minimum eRBEDSB values were also related to iron (Fe) NPs at the entire range of studied photon energies. CONCLUSIONS The compared nanoscale physical and biological results of our study can be helpful in the selection of optimum NP as a radiosensitizer in future radiobiological studies. Bi, gold (Au), Ag, and platinum (Pt) NPs had great potential, respectively, as radiosensitizers relative to the other studied NPs.
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Affiliation(s)
- Mostafa Robatjazi
- Medical Physics and Radiological Sciences Department, Sabzevar University of Medical Sciences, Sabzevar, Iran
- Non-Communicable Diseases Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | | | - Atefeh Rostami
- Medical Physics and Radiological Sciences Department, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Ali Pashazadeh
- Institute for Medical Technology, Otto von Guericke University, Magdeburg, Germany
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Baghani HR, Nasrollahi S. Efficacy of various nanoparticle types in dose enhancement during low energy X-ray IORT: A Monte Carlo simulation study. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kyriakou I, Tremi I, Georgakilas AG, Emfietzoglou D. Microdosimetric investigation of the radiation quality of low-medium energy electrons using Geant4-DNA. Appl Radiat Isot 2021; 172:109654. [PMID: 33676082 DOI: 10.1016/j.apradiso.2021.109654] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/17/2021] [Accepted: 02/20/2021] [Indexed: 02/06/2023]
Abstract
The increasing clinical use of low-energy photon and electron sources (below few tens of keV) has raised concerns on the adequacy of the existing approximation of an energy-independent radiobiological effectiveness. In this work, the variation of the quality factor (Q) and relative biological effectiveness (RBE) of electrons over the low-medium energy range (0.1 keV-1 MeV) is examined using several microdosimetry-based Monte Carlo methodologies with input data obtained from Geant4-DNA track-structure simulations. The sensitivity of the results to the different methodologies, Geant4-DNA physics models, and target sizes is examined. Calculations of Q and RBE are based on the ICRU Report 40 recommendations, the Kellerer-Hahn approximation, the site version of the theory of dual radiation action (TDRA), the microdosimetric kinetic model (MKM) of cell survival, and the calculated yield of DNA double strand breaks (DSB). The stochastic energy deposition spectra needed as input in the above approaches have been calculated for nanometer spherical volumes using the different electron physics models of Geant4-DNA. Results are normalized at 100 keV electrons which is here considered the reference radiation. It is shown that in the energy range ~50 keV-1 MeV, the calculated Q and RBE are approximately unity (to within 1-2%) irrespective of the methodology, Geant4-DNA physics model, and target size. At lower energies, Q and RBE become energy-dependent reaching a maximum value of ~1.5-2.5 between ~200 and 700 eV. The detailed variation of Q and RBE at low energies depends mostly upon the adopted methodology and target size, and less so upon the Geant4-DNA physics model. Overall, the DSB yield predicts the highest RBE values (with RBEmax≈2.5) whereas the MKM the lowest RBE values (with RBEmax≈1.5). The ICRU Report 40, Kellerer-Hahn, and TDRA methods are in excellent agreement (to within 1-2%) over the whole energy range predicting a Qmax≈2. In conclusion, the approximation Q=RBE=1 was found to be valid only above ~50 keV whereas at lower energies both Q and RBE become strongly energy-dependent. It is envisioned that the present work will contribute towards establishing robust methodologies to determine theoretically the energy-dependence of radiation quality of individual electrons which may then be used in subsequent calculations involving practical electron and photon radiation sources.
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Affiliation(s)
- Ioanna Kyriakou
- Medical Physics Laboratory, University of Ioannina Medical School, 45110, Ioannina, Greece.
| | - Ioanna Tremi
- DNA Damage Laboratory, Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou, Athens, Greece
| | - Alexandros G Georgakilas
- DNA Damage Laboratory, Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou, Athens, Greece
| | - Dimitris Emfietzoglou
- Medical Physics Laboratory, University of Ioannina Medical School, 45110, Ioannina, Greece
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7
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Ayala Alvarez DS, G F Watson P, Popovic M, Jean Heng V, Evans MDC, Seuntjens J. Monte Carlo calculation of the relative TG-43 dosimetry parameters for the INTRABEAM electronic brachytherapy source. Phys Med Biol 2020; 65:245041. [PMID: 33137796 DOI: 10.1088/1361-6560/abc6f1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The INTRABEAM system (Carl Zeiss Meditec AG, Jena, Germany) is an electronic brachytherapy (eBT) device designed for intraoperative radiotherapy applications. To date, the INTRABEAM x-ray source has not been characterized according to the AAPM TG-43 specifications for brachytherapy sources. This restricts its modelling in commercial treatment planning systems (TPSs), with the consequence that the doses to organs at risk are unknown. The aim of this work is to characterize the INTRABEAM source according to the TG-43 brachytherapy dosimetry protocol. The dose distribution in water around the source was determined with Monte Carlo (MC) calculations. For the validation of the MC model, depth dose calculations along the source longitudinal axis were compared with measurements using a soft x-ray ionization chamber (PTW 34013) and two synthetic diamond detectors (microDiamond PTW TN60019). In our results, the measurements in water agreed with the MC model calculations within uncertainties. The use of the microDiamond detector yielded better agreement with MC calculations, within estimated uncertainties, compared to the ionization chamber at points of steeper dose gradients. The radial dose function showed a steep fall-off close to the INTRABEAM source ([Formula: see text]10 mm) with a gradient higher than that of commonly used brachytherapy radionuclides (192Ir, 125I and 103Pd), with values of 2.510, 1.645 and 1.232 at 4, 6 and 8 mm, respectively. The radial dose function partially flattens at larger distances with a fall-off comparable to that of the Xoft Axxent® (iCAD, Inc., Nashua, NH) eBT system. The simulated 2D polar anisotropy close to the bare probe walls showed deviations from unity of up to 55% at 10 mm and 155°. This work presents the MC calculated TG-43 parameters for the INTRABEAM, which constitute the necessary data for the characterization of the source as required by a TPS used in clinical dose calculations.
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Affiliation(s)
| | - Peter G F Watson
- Medical Physics Unit, McGill University and Cedars Cancer Center, Montreal, Canada
| | - Marija Popovic
- Medical Physics Unit, McGill University and Cedars Cancer Center, Montreal, Canada
| | - Veng Jean Heng
- Medical Physics Unit, McGill University and Cedars Cancer Center, Montreal, Canada
| | - Michael D C Evans
- Medical Physics Unit, McGill University and Cedars Cancer Center, Montreal, Canada
| | - Jan Seuntjens
- Medical Physics Unit, McGill University and Cedars Cancer Center, Montreal, Canada
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Udroiu I, Sgura A, Chendi A, Lasagni L, Bertolini M, Fioroni F, Piccagli V, Moramarco A, Romano MG, Fontana L, D'Alessio D, Bruzzaniti V, Rosi A, Grande S, Palma A, Giliberti C, Iori M, Piergallini L, Sumini M, Isolan L, Cucchi G, Compagnone G, Strigari L. DNA damage in lens epithelial cells exposed to occupationally-relevant X-ray doses and role in cataract formation. Sci Rep 2020; 10:21693. [PMID: 33303795 PMCID: PMC7728785 DOI: 10.1038/s41598-020-78383-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 10/28/2020] [Indexed: 11/09/2022] Open
Abstract
The current framework of radiological protection of occupational exposed medical workers reduced the eye-lens equivalent dose limit from 150 to 20 mSv per year requiring an accurate dosimetric evaluation and an increase understanding of radiation induced effects on Lens cells considering the typical scenario of occupational exposed medical operators. Indeed, it is widely accepted that genomic damage of Lens epithelial cells (LEC) is a key mechanism of cataractogenesis. However, the relationship between apoptosis and cataractogenesis is still controversial. In this study biological and physical data are combined to improve the understanding of radiation induced effects on LEC. To characterize the occupational exposure of medical workers during angiographic procedures an INNOVA 4100 (General Electric Healthcare) equipment was used (scenario A). Additional experiments were conducted using a research tube (scenario B). For both scenarios, the frequencies of binucleated cells, micronuclei, p21-positive cells were assessed with different doses and dose rates. A Monte-Carlo study was conducted using a model for the photon generation with the X-ray tubes and with the Petri dishes considering the two different scenarios (A and B) to reproduce the experimental conditions and validate the irradiation setups to the cells. The simulation results have been tallied using the Monte Carlo code MCNP6. The spectral characteristics of the different X-ray beams have been estimated. All irradiated samples showed frequencies of micronuclei and p21-positive cells higher than the unirradiated controls. Differences in frequencies increased with the delivered dose measured with Gafchromic films XR-RV3. The spectrum incident on eye lens and Petri, as estimated with MCNP6, was in good agreement in the scenario A (confirming the experimental setup), while the mean energy spectrum was higher in the scenario B. Nevertheless, the response of LEC seemed mainly related to the measured absorbed dose. No effects on viability were detected. Our results support the hypothesis that apoptosis is not responsible for cataract induced by low doses of X-ray (i.e. 25 mGy) while the induction of transient p21 may interfere with the disassembly of the nuclear envelop in differentiating LEC, leading to cataract formation. Further studies are needed to better clarify the relationship we suggested between DNA damage, transient p21 induction and the inability of LEC enucleation.
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Affiliation(s)
- Ion Udroiu
- Department of Science, University of Rome "Roma Tre", Rome, Italy
| | - Antonella Sgura
- Department of Science, University of Rome "Roma Tre", Rome, Italy
| | - Agnese Chendi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy.,Postgraduate School in Medical Physics, University of Bologna, Bologna, Italy
| | - Lorenzo Lasagni
- Postgraduate School in Medical Physics, University of Firenze, Florence, Italy
| | - Marco Bertolini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | - Federica Fioroni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | - Vando Piccagli
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | - Antonio Moramarco
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | | | - Luigi Fontana
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | - Daniela D'Alessio
- Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Vicente Bruzzaniti
- Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Institute IRCCS, Rome, Italy
| | - Antonella Rosi
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Sveva Grande
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Alessandra Palma
- Istituto Superiore di Sanità, Centro Nazionale Tecnologie Innovative in Sanità Pubblica, Rome, Italy
| | - Claudia Giliberti
- Inail-Dipartimento Innovazioni Tecnologiche e Sicurezza degli Impianti, Prodotti ed Insediamenti Antropici, Rome, Italy
| | - Mauro Iori
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy
| | - Lorenzo Piergallini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio, Italy.,Montecuccolino Laboratory, Industrial Engineering Department, University of Bologna, Bologna, Italy
| | - Marco Sumini
- Montecuccolino Laboratory, Industrial Engineering Department, University of Bologna, Bologna, Italy.,INFN, Bologna, Italy.,Interdepartmental Center "L. Galvani" CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
| | - Lorenzo Isolan
- Montecuccolino Laboratory, Industrial Engineering Department, University of Bologna, Bologna, Italy.,Interdepartmental Center "L. Galvani" CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
| | - Giorgio Cucchi
- Montecuccolino Laboratory, Industrial Engineering Department, University of Bologna, Bologna, Italy.,Interdepartmental Center "L. Galvani" CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
| | - Gaetano Compagnone
- Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Lidia Strigari
- Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy.
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Shamsabadi R, Baghani HR, Azadegan B, Mowlavi AA. Influence of breast tissue composition on dosimetric characteristics of therapeutic low energy X-rays. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.109110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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10
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Shamsabadi R, Baghani HR, Azadegan B, Mowlavi AA. Impact of spherical applicator diameter on relative biologic effectiveness of low energy IORT X-rays: A hybrid Monte Carlo study. Phys Med 2020; 80:297-307. [DOI: 10.1016/j.ejmp.2020.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/07/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022] Open
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11
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Watson PGF, Popovic M, Liang L, Tomic N, Devic S, Seuntjens J. Clinical Implication of Dosimetry Formalisms for Electronic Low-Energy Photon Intraoperative Radiation Therapy. Pract Radiat Oncol 2020; 11:e114-e121. [PMID: 32795615 DOI: 10.1016/j.prro.2020.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 05/27/2020] [Accepted: 07/27/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE Intraoperative radiation therapy (IORT) using the INTRABEAM, a miniature x-ray source, has shown to be effective in treating breast cancer. However, recent investigations have suggested a significant deviation between the reported and delivered doses. In this work, the dose delivered by INTRABEAM in the TARGIT breast protocol was investigated, along with the dose from the Xoft Axxent, another source used in breast IORT. METHODS AND MATERIALS The absorbed dose from the INTRABEAM was determined from ionization chamber measurements using: (a) the manufacturer-recommended formula (Zeiss V4.0 method), (b) a Monte Carlo calculated chamber conversion factor (CQ method), and (c) the formula consistent with the TARGIT breast protocol (TARGIT method). The dose from the Xoft Axxent was determined from ionization chamber measurements using the Zeiss V4.0 method and calculated using the American Association of Physicists in Medicine TG-43 formalism. RESULTS For a nominal TARGIT prescription of 20 Gy, the dose at the INTRABEAM applicator surface ranged from 25.2 to 31.7 Gy according to the CQ method for the largest (5 cm) and smallest (1.5 cm) diameter applicator, respectively. The Zeiss V4.0 method results were 7% to 10% lower (23.2 to 28.6 Gy). At 1 cm depth, the CQ and Zeiss V4.0 absorbed doses were also larger than those predicted by the TARGIT method. The dose at 1 cm depth from the Xoft Axxent for a surface dose of 20 Gy was slightly less than INTRABEAM (3%-7% compared with CQ method). An exception was for the 3 cm applicator, where the Xoft dose was appreciably lower (31%). CONCLUSIONS The doses delivered in the TARGIT breast protocol with INTRABEAM were significantly greater than the prescribed 20 Gy and depended on the size of spherical applicator used. Breast IORT treatments with the Xoft Axxent received less dose compared with TARGIT INTRABEAM, which could have implications for studies comparing clinical outcomes between the 2 devices.
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Affiliation(s)
| | - Marija Popovic
- Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Liheng Liang
- Medical Physics Unit, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Nada Tomic
- Medical Physics Unit, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Slobodan Devic
- Medical Physics Unit, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Jan Seuntjens
- Medical Physics Unit, McGill University, Montreal, QC, Canada
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12
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Shaikh MY, Burmeister J, Scott R, Kumaraswamy LK, Nalichowski A, Joiner MC. Dosimetric evaluation of incorporating the revised V4.0 calibration protocol for breast intraoperative radiotherapy with the INTRABEAM system. J Appl Clin Med Phys 2020; 21:50-59. [PMID: 32039545 PMCID: PMC7020998 DOI: 10.1002/acm2.12807] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/20/2019] [Accepted: 12/10/2019] [Indexed: 12/18/2022] Open
Abstract
In breast‐targeted intraoperative radiotherapy (TARGIT) clinical trials (TARGIT‐B, TARGIT‐E, TARGIT‐US), a single fraction of radiation is delivered to the tumor bed during surgery with 1.5‐ to 5.0‐cm diameter spherical applicators and an INTRABEAM x‐ray source (XRS). This factory‐calibrated XRS is characterized by two depth‐dose curves (DDCs) named "TARGIT" and "V4.0.” Presently, the TARGIT DDC is used to treat patients enrolled in clinical trials; however, the V4.0 DDC is shown to better represent the delivered dose. Therefore, we reevaluate the delivered prescriptions under the TARGIT protocols using the V4.0 DDC. A 20‐Gy dose was prescribed to the surface of the spherical applicator, and the TARGIT DDC was used to calculate the treatment time. For a constant treatment time, the V4.0 DDC was used to recalculate the dosimetry to evaluate differences in dose rate, dose, and equivalent dose in 2‐Gy fractions (EQD2) for an α/β = 3.5 Gy (endpoint of locoregional relapse). At the surface of the tumor bed (i.e., spherical applicator surface), the calculations using the V4.0 DDC predicted increased values for dose rate (43–16%), dose (28.6–23.2 Gy), and EQD2 (95–31%) for the 1.5‐ to 5.0‐cm diameter spherical applicator sizes, respectively. In general, dosimetric differences are greatest for the 1.5‐cm diameter spherical applicator. The results from this study can be interpreted as a reevaluation of dosimetry or the dangers of underdosage, which can occur if the V4.0 DDC is inadvertently used for TARGIT clinical trial patients. Because the INTRABEAM system is used in TARGIT clinical trials, accurate knowledge about absorbed dose is essential for making meaningful comparisons between radiation treatment modalities, and reproducible treatment delivery is imperative. The results of this study shed light on these concerns.
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Affiliation(s)
- Mubin Y Shaikh
- Department of Radiation Oncology, Rochester Regional, Rochester, NY, USA
| | - Jay Burmeister
- Wayne State University School of Medicine, Gershenson Radiation Oncology Center, Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | | | - Lalith K Kumaraswamy
- Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Adrian Nalichowski
- Wayne State University School of Medicine, Gershenson Radiation Oncology Center, Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | - Michael C Joiner
- Department of Oncology, Gershenson Radiation Oncology Center, Wayne State University, Detroit, USA
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Nusrat H, Karim-Picco S, Pang G, Paudel M, Sarfehnia A. Maximum RBE change in 192Ir, 125I, and 169Yb brachytherapy and the corresponding effect on treatment planning. Biomed Phys Eng Express 2020; 6:015021. [PMID: 33438609 DOI: 10.1088/2057-1976/ab638e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE The purpose of this study was to examine RBE variation as a function of distance from the radioactive source, and the potential impact of this variation on a realistic prostate brachytherapy treatment plan. METHODS Three brachytherapy sources (125I, 192Ir, and 169Yb) were modelled in Geant4 Monte Carlo code, and the resulting electron energy spectrum in water in 3D space around these sources was scored (voxel size of 2 mm3). With this energy spectrum, microdosimetric techniques were used to calculate the maximum RBE, RBEM, as a function of distance from the source. RBEM of 125I relative to 192Ir was calculated in order to validate simulations against literature; all other RBEM calculations were done by normalizing electron fluence at various distances to the source position. In order to examine the impact of RBEM variation in treatment planning, a realistic 192Ir prostate plan was re-evaluated in terms of RBE instead of absorbed dose. RESULTS The RBEM of 125I, 192Ir, and 169Yb at 8 cm away from the source was 0.994 (+/-0.002), 1.030 (+/-0.003), and 1.066 (+/-0.008), respectively. RBEM in the HDR prostate treatment plan exhibited several hot (+3.6% in RBEM) spots. CONCLUSIONS The large increase RBEM observed in 169Yb has not yet been described in the literature. Despite the presence of radiobiological hotspots in the HDR treatment, these variations are likely nominal and clinically insignificant.
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Affiliation(s)
- Humza Nusrat
- Department of Physics, Ryerson University, 350 Victoria St., M5B 2K3 Toronto, ON, Canada
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14
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Postoperative endometrial cancer treatments with electronic brachytherapy source. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396918000353] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractPurposeThis study is a dosimetric and acute toxicity comparison of endometrial cancer patients treated with either Axxent (Xoft, Inc., San José, CA, USA) electronic and interstitial brachytherapy versus interstitial high dose rate brachytherapy (HDRBT).Materials and MethodsBetween 2015 and 2017, 94 patients with postoperative endometrial cancer were treated in our centre with the Axxent electronic brachytherapy (eBT) system. The V150 and V200 are evaluated prospectively for each plan. The mean age of patients was 65.9 years (age range 33–84 years), with different tumour staging. Of the 94 patients, 37 received exclusive adjuvant brachytherapy (25 Gy in five sessions); the remaining patients received external beam radiotherapy (EBRT) with a regimen of 23 sessions of 2 Gy each to the entire pelvis, followed by eBT (15 Gy in three sessions). Additionally, the absorbed doses received by the organs at risk (OAR), urinary bladder, rectum and sigmoid colon were compared with HDRBT plans, evaluating D2cc, V50% and V35%. Median follow-up was done for each of the 94 patients to assess the toxicity of the treatment: vaginal mucosa toxicity, rectal and urinary toxicity; and results are presented for acute toxicity, toxicity at 1 month after the end of treatment and follow-up after 12 months for a portion of patients according to the Radiation Therapy Oncology Group (RTOG) toxicity criteria.ResultsThe doses in OAR for eBT plans were lower than that for HDRBT plans, both Ir-192 and Co-60 plans, whose doses were similar. The dose in bladder with eBT was 63.8% of the prescribed dose for D2cc versus 70.1% for HDRBT Ir-192, for V50% was 7.2% versus 12.7% and for V35% was 15.2% versus 28.2%. In rectum the D2cc was 61.2% versus 68.4%, for V50% was 7.9% versus 14.3% and for V35% was 16.7% versus 32%. Results demonstrated lower doses to OAR in all eBT plans. Acute toxicity in eBT was very low in cases of mucositis, with only one case of toxicity greater than grade 1, rectal toxicity and urinary toxicity; results at 1 month are equally good, toxicity symptoms disappeared and no relapses have occurred to date.ConclusionsThe results of treatment with the Axxent eBT unit for 94 patients are very good, as no recurrence has been observed and the toxicity of the treatment is very low. The increase in V150 and V200 has not produced an increase in vaginal mucosa toxicity, and the doses in the OAR are lower than in the plans implemented for HDRBT with Ir-192 or Co-60. eBT is a good alternative to treat endometrial cancer in centres without conventional HDR availability. To date, there are limited published studies reporting on outcomes from patients treated with eBT.
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Watson PGF, Bekerat H, Papaconstadopoulos P, Davis S, Seuntjens J. An investigation into the INTRABEAM miniature x-ray source dosimetry using ionization chamber and radiochromic film measurements. Med Phys 2018; 45:4274-4286. [PMID: 29935088 DOI: 10.1002/mp.13059] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/22/2018] [Accepted: 06/15/2018] [Indexed: 02/28/2024] Open
Abstract
PURPOSE Intraoperative radiotherapy using The INTRABEAM System (Carl Zeiss Meditec AG, Jena, Germany), a miniature low-energy x-ray source, has proven to be an effective modality in the treatment of breast cancer. However, some uncertainties remain in its dosimetry. In this work, we investigated the INTRABEAM system dosimetry by performing ionization chamber and radiochromic film measurements of absorbed dose in a water phantom. METHODS Ionization chamber measurements were performed with a PTW 34013 parallel-plate soft x-ray chamber at source to detector distances of 5 to 30 mm calculated using (a) the dose formula consistent with the TARGIT breast protocol (TARGIT), (b) the formula recommended by the manufacturer (Zeiss), and (c) the recently proposed CQ formalism of Watson et al. (Physics in Medicine & Biology, 2018;63:015016) EBT3 Gafchromic film measurements were made at the same depths in water. To account for the energy dependence of EBT3 film, multiple dose response calibration curves were employed across a range of photon beam qualities relevant to the INTRABEAM spectrum in water. RESULTS At all depths investigated, the TARGIT dose was significantly lower than that measured by the Zeiss and CQ methods, as well as film. These dose differences ranged from 14% to as large as 80%. In general, the doses measured by film, and the Zeiss and CQ methods were in good agreement to within measurement uncertainties (5-6%). CONCLUSIONS These results suggest that the TARGIT dose underestimates the physical dose to water from the INTRABEAM source. Understanding the correlation between the TARGIT and physical dose is important for any studies wishing to make dosimetric comparisons between the INTRABEAM and other radiation emitting devices.
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Affiliation(s)
| | - Hamed Bekerat
- Medical Physics Unit, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Pavlos Papaconstadopoulos
- Medical Physics Unit, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Stephen Davis
- Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Jan Seuntjens
- Medical Physics Unit, McGill University, Montreal, QC, Canada
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Famulari G, Pater P, Enger SA. Microdosimetric Evaluation of Current and Alternative Brachytherapy Sources—A Geant4-DNA Simulation Study. Int J Radiat Oncol Biol Phys 2018; 100:270-277. [DOI: 10.1016/j.ijrobp.2017.09.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/09/2017] [Accepted: 09/18/2017] [Indexed: 12/12/2022]
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Moradi F, Ung NM, Khandaker MU, Mahdiraji GA, Saad M, Abdul Malik R, Bustam AZ, Zaili Z, Bradley DA. Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators. ACTA ACUST UNITED AC 2017; 62:6550-6566. [DOI: 10.1088/1361-6560/aa7fe6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Maitz CA, Robinson KL. Use of an electronic brachytherapy surface applicator to treat an epiglottal fibrosarcoma in a dog. Vet Radiol Ultrasound 2017; 58:E45-E48. [PMID: 28436129 DOI: 10.1111/vru.12503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/17/2017] [Accepted: 01/29/2017] [Indexed: 11/29/2022] Open
Abstract
Presented is the case of an epiglottal fibrosarcoma in a dog. The location of the mass resulted in challenges in the delivery of adequate dose to the tumor, and herein we describe the treatment using an electronic brachytherapy source. The treatment consisted of four Gy fractions, twice daily for a total of 10 fractions (40 Gy total). Visual reevaluation two weeks after treatment supported adequate spatial dose delivery, and the patient was reportedly improved six weeks after treatment. We demonstrate that plesiotherapy using an electronic brachytherapy device is feasible and may be useful in the treatment of carefully selected veterinary tumors.
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Affiliation(s)
- Charles A Maitz
- Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211
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Ebert MA, Dhal B, Prunster J, McLaren S, Zeps N, House M, Reniers B, Verhaegen F, Corica T, Saunders C, Joseph DJ. Theoretical versus Ex Vivo Assessment of Radiation Damage Repair: An Investigation in Normal Breast Tissue. Radiat Res 2016; 185:393-401. [PMID: 27023258 DOI: 10.1667/rr14235.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In vivo validation of models of DNA damage repair will enable their use for optimizing clinical radiotherapy. In this study, a theoretical assessment was made of DNA double-strand break (DSB) induction in normal breast tissue after intraoperative radiation therapy (IORT), which is now an accepted form of adjuvant radiotherapy for selected patients with early breast cancer. DSB rates and relative biological effectiveness (RBE) were calculated as a function of dose, radiation quality and dose rate, each varying based on the applicator size used during IORT. The spectra of primary electrons in breast tissue adjacent to each applicator were calculated using measured X-ray spectra and Monte Carlo methods, and were used to inform a Monte Carlo damage simulation code. In the absence of repair, asymptotic RBE values (relative to (60)Co) were approximately 1.5. Beam-quality changes led to only minor variations in RBE among applicators, though differences in dose rate and overall dose delivery time led to larger variations and a rapid decrease in RBE. An experimental assessment of DSB induction was performed ex vivo using pre- and postirradiation tissue samples from patients receiving breast intraoperative radiation therapy. Relative DSB rates were assessed via γ-H2AX immunohistochemistry using proportional staining. Maximum-likelihood parameter estimation yielded a DSB repair halftime of 25.9 min (95% CI, 21.5-30.4 min), although the resulting model was not statistically distinguishable from one where there was no change in DSB yield among patients. Although the model yielded an in vivo repair halftime of the order of previous estimates for in vitro repair halftimes, we cannot conclude that it is valid in this context. This study highlights some of the uncertainties inherent in population analysis of ex vivo samples, and of the quantitative limitations of immunohistochemistry for assessment of DSB repair.
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Affiliation(s)
- Martin A Ebert
- a Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia; Schools of.,b Physics
| | | | - Janelle Prunster
- a Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia; Schools of
| | - Sally McLaren
- e St. John of God Subiaco Hospital, Western Australia
| | - Nikolajs Zeps
- c Surgery and.,e St. John of God Subiaco Hospital, Western Australia
| | | | - Brigitte Reniers
- f Research Group NuTeC, CMK, Hasselt University, Diepenbeek, Belgium; and
| | | | - Tammy Corica
- a Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia; Schools of.,d Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia
| | | | - David J Joseph
- a Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia; Schools of.,c Surgery and
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