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Hashemi S, Aghamiri SMR, Siavashpour Z, Kahani M, Zaidi H, Jaberi R. Hydrogen nanobubbles: A novel approach toward radio-sensitization agents. Med Phys 2023; 50:6589-6599. [PMID: 37278345 DOI: 10.1002/mp.16521] [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: 07/27/2022] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND Ocular melanoma is a rare kind of eye malignancy that threatens the patient's eyesight. Radiotherapy and surgical removal are the most commonly used therapeutic modalities, and nanomedicine has lately entered this field. Brachytherapy using Ruthenium-106 (106 Ru) ophthalmic plaques has been used for decades to treat ocular melanoma, with the applicator placed on the patient's eyes until the prescribed dose reaches the tumor apex. PURPOSE To investigate the efficiency of hydrogen nanobubbles (H2 -NBs) employment during intraocular melanoma brachytherapy using a 106 Ru electron emitter plaque. METHODS The Monte Carlo (MC) simulation and experimental investigation using a 3D-designed phantom and thermoluminescence dosimetry (TLD) were employed. Various concentrations of H2 -NBs with a diameter of 100 nm were simulated inside tumor tissue. The results were presented as deposited energy and dose enhancement factor (DEF). An equivalent Resin phantom of the human eyeball was made using AutoCAD and 3D-Printer technologies. The glass-bead TLDs dosimeter were employed and placed inside the phantom. RESULTS Using a 1% concentration of H2 -NBs, a DEF of 93% and 98% were achieved at the tumor apex of 10 mm from the experimental setup and MC simulation, respectively. For simulated concentrations of 0.1%, 0.3%, 0.5%, 1%, and 4% H2 -NBs, a maximum dose enhancement of 154%, 174%, 188%, 200%, and 300% were achieved, respectively, and a dose reduction was seen at about 3 mm from the plaque surface. CONCLUSION H2 -NBs can be used as an absorbed dose enhancer in 106 Ru eye brachytherapy because of their unique physical characteristics. Reducing plaque implantation time on the patient's eye, reducing sclera absorbed dose, and decreasing the risk of patients' healthy organs irradiation are reported as some of the potential benefits of using H2-NBs.
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Affiliation(s)
- Samaneh Hashemi
- Medical Radiation Department, Shahid Beheshti University, Tehran, Iran
| | | | - Zahra Siavashpour
- Radiotherapy Oncology Department, Shohada Tajrish Educational Hospital, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Mahdi Kahani
- Medical Radiation Department, Shahid Beheshti University, Tehran, Iran
| | - Habib Zaidi
- Geneva University Neurocenter, Geneva University, Geneva, Switzerland
| | - Ramin Jaberi
- Cancer Institute, Tehran University of Medical Science, Tehran, Iran
- Medical Physics Department, Surrey University, Guildford, UK
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Taherparvar P, Fardi Z. Comparison between dose distribution from 103Pd, 131Cs, and 125I plaques in a real human eye model with different tumor size. Appl Radiat Isot 2022; 182:110146. [DOI: 10.1016/j.apradiso.2022.110146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 11/17/2022]
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Iori M, Isolan L, Piergallini L, Chendi A, Lasagni L, Cucchi G, Bertolini M, Fioroni F, Piccagli V, Moramarco A, Romano MG, Fontana L, Strigari L, D'Alessio D, Bruzzaniti V, Sgura A, Udroiu I, Rosi A, Grande S, Palma A, Giliberti C, Sumini M. How direct measurements of worker eyes with a Scheimpflug camera can affect lensdose coefficients in interventional radiology. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:689-706. [PMID: 33827064 DOI: 10.1088/1361-6498/abf56f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The 2013/59/Euratom Directive reduced the occupational exposure limits for the lens. Since it has become crucial to estimate the dose absorbed by the lens, we have studied the individual variability of exposed workers' ocular conformations with respect to the data estimated from their personal dosimetry. The anterior eye conformations of 45 exposed workers were acquired using Scheimpflug imaging and classified according to their sight conditions (emmetropia, myopia or hypermetropia). Three eye models were computed, with two lens reconstructions, and implemented in an interventional radiology scenario using Monte Carlo code. The models were dosimetrically analysed by simulating setup A, a theoretical monoenergetic and isotropic photon source (10-150 keV) and setup B, a more realistic interventional setting with an angiographic x-ray unit (50, 75, 100 kV peak). Scheimpflug imaging provided an average anterior chamber depth of (6.4 ± 0.5) mm and a lens depth of (3.9 ± 0.3) mm, together with a reconstructed equatorial lens length of (7.1-10.1) mm. Using these data for model reconstruction, dose coefficients (DCs) were simulated for all ocular structures. Regardless of the eye model used, the DCs showed a similar trend with radiation energy, which highlighted that for the same energy and setup, no significant dependence on ocular morphology and workers' visual conditions was observed. The maximum difference obtained did not exceed 1% for all eye models or structures analysed. Therefore, the individual variabilities of worker ocular anatomy do not require any additional correction, compared to the personal dosimetry data measured with a dedicated lens dosimeter. To estimate the dose absorbed by the other eye structures, it is, instead, essential to know the spectrum of the source that has generated the irradiation, since there are differences between monoenergetic sources and more realistic angiographic units.
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Affiliation(s)
- Mauro Iori
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Lorenzo Isolan
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
- INFN, Bologna, Italy
| | - Lorenzo Piergallini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Agnese Chendi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
- Medical Physics, University of Bologna, Bologna, Italy
| | - Lorenzo Lasagni
- Postgraduate school in Medical Physics, University of Firenze, Firenze, Italy
| | - Giorgio Cucchi
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
| | - Marco Bertolini
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Federica Fioroni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Vando Piccagli
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Antonio Moramarco
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Maria Grazia Romano
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Luigi Fontana
- Ophthalmology Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Lidia Strigari
- Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Daniela D'Alessio
- Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Institute IRCCS, Rome, Italy
| | - Vicente Bruzzaniti
- Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Institute IRCCS, Rome, Italy
| | - Antonella Sgura
- Department of Science, University of Rome 'Roma Tre', Rome, Italy
| | - Ion Udroiu
- Department of Science, University of Rome 'Roma Tre', 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
| | - Marco Sumini
- University of Bologna, Industrial Engineering Department, Montecuccolino Laboratory, Bologna, Italy
- Interdepartmental Center 'L. Galvani' CIG, Alma Mater Studiorum Università di Bologna, Bologna, Italy
- INFN, Bologna, Italy
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Dupere JM, Munro JJ, Medich DC. Intensity modulated high dose rate ocular brachytherapy using Se-75. Brachytherapy 2021; 20:1312-1322. [PMID: 34561174 DOI: 10.1016/j.brachy.2021.08.004] [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: 01/22/2021] [Revised: 06/16/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE We propose an alternative to LDR brachytherapy for the treatment of ocular melanomas by coupling intensity modulation, through the use of a gold shielded ring applicator, with a middle energy HDR brachytherapy source, Se-75. In this study, we computationally test this proposed design using MCNP6. METHODS AND MATERIALS An array of discrete Se-75 sources is formed into a ring configuration within a gold shielded applicator, which collimates the beam to a conical shape. Varying this angle of collimation allows for the prescription dose to be delivered to the apex of various sized targets. Simulations in MCNP6 were performed to calculate the dosimetric output of the Se-75 ring source for various sized applicators, collimators, and target sizes. RESULTS The prescription dose was delivered to a range of target apex depths 3.5-8 mm in the eye covering targets 10-15 mm in diameter by using various sized applicators and collimators. For a 16 mm applicator with a collimator opening that delivers the prescription dose to a depth of 5 mm in the eye, the maximum percent dose rate to critical structures was 30.5% to the cornea, 35.7% to the posterior lens, 33.3% to the iris, 20.1% to the optic nerve, 278.0% to the sclera, and 267.3% to the tumor. CONCLUSIONS When using Se-75 in combination with the proposed gold shielded ring applicator, dose distributions are appropriate for ocular brachytherapy. The use of a collimator allows for the dose to more easily conform to the tumor volume. This method also reduces treatment time and cost, and it eliminates hand dose to the surgeon through the use of a remote afterloader device.
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Kamrani S, Aghamiri SMR, Hashemi S. Dose characteristics of Au-198 eye brachytherapy applicator: A Monte Carlo study. Appl Radiat Isot 2021; 176:109866. [PMID: 34293507 DOI: 10.1016/j.apradiso.2021.109866] [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: 01/18/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE The use of ocular plaques is a promising treatment option for eye melanoma brachytherapy. Although several studies have been done on various ocular plaques, little is known about the dose characterization of 198Au plaque. MATERIALS AND METHOD The full mathematical model of the eye phantom, tumor, 106Ru/106Rh CCA, and 198Au plaque were simulated using the Monte Carlo MCNPX code. The dose distribution was measured in the plaque's central axis direction, and a dose profile was also measured at a distance of 2.5 mm from the plaque surface. RESULTS The findings showed that 198Au plaque has superior dosimetric characteristics than CCA plaque for tumors with a thickness of greater than 3.5 mm, while CCA plaque is better for tumors with a thickness of less than 3.5 mm. The dose to the sclera and choroid is higher in the case of CCA plaque, while the dose to the organs at risk (lens and optic nerve) is greater in the case of 198Au applicator. In the case of 198Au plaque, however, the dose to sensitive organs was within their permissible dose range. CONCLUSION In the treatment of medium and large tumors, 198Au plaque is more successful than CCA plaque. It can produce a much more homogeneous lateral dose profile in the target. In the treatment of dome-shaped tumors, 198Au plaque may be more successful than CCA plaque. As a result, the tumor's shape influences the plaque type selection.
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Affiliation(s)
- Samira Kamrani
- Medical Radiation Department, Shahid Beheshti University, Tehran, Iran
| | | | - Samaneh Hashemi
- Medical Radiation Department, Shahid Beheshti University, Tehran, Iran
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Miras Del Río H, Ortiz Lora A, Bertolet Reina A, Terrón León JA. A Monte Carlo dose calculation system for ophthalmic brachytherapy based on a realistic eye model. Med Phys 2021; 48:4542-4559. [PMID: 34250607 DOI: 10.1002/mp.15045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/11/2021] [Accepted: 06/03/2021] [Indexed: 01/13/2023] Open
Abstract
PURPOSE There is a growing trend towards the adoption of model-based calculation algorithms (MBDCAs) for brachytherapy dose calculations which can properly handle media and source/applicator heterogeneities. However, most of dose calculations in ocular plaque therapy are based on homogeneous water media and standard in-silico ocular phantoms, ignoring non-water equivalency of the anatomic tissues and heterogeneities in applicators and patient anatomy. In this work, we introduce EyeMC, a Monte Carlo (MC) model-based calculation algorithm for ophthalmic plaque brachytherapy using realistic and adaptable patient-specific eye geometries and materials. METHODS We used the MC code PENELOPE in EyeMC to model Bebig IsoSeed I25.S16 seeds in COMS plaques and 106 Ru/106 Rh applicators that are coupled onto a customizable eye model with realistic geometry and composition. To significantly reduce calculation times, we integrated EyeMC with CloudMC, a cloud computing platform for radiation therapy calculations. EyeMC is equipped with an evaluation module that allows the generation of isodose distributions, dose-volume histograms, and comparisons with Plaque Simulator three-dimensional dose distribution. We selected a sample of patients treated with 125 I and 106 Ru isotopes in our institution, covering a variety of different type of plaques, tumor sizes, and locations. Results from EyeMC were compared to the original plan calculated by the TPS Plaque Simulation, studying the influence of heterogeneous media composition as well. RESULTS EyeMC calculations for Ru plaques agreed well with manufacturer's reference data and data of MC simulations from Hermida et al. (2013). Significant deviations, up to 20%, were only found in lateral profiles for notched plaques. As expected, media composition significantly affected estimated doses to different eye structures, especially in the 125 I cases evaluated. Dose to sclera and lens were found to be about 12% lower when considering real media, while average dose to tumor was 9% higher. 106 Ru cases presented a 1%-3% dose reduction in all structures using real media for calculation, except for the lens, which showed an average dose 7.6% lower than water-based calculations. Comparisons with Plaque Simulator calculations showed large differences in dose to critical structures for 106 Ru notched plaques. 125 I cases presented significant and systematic dose deviations when using the default calculation parameters from Plaque Simulator version 5.3.8., which were corrected when using calculation parameters from a custom physics model for carrier-attenuation and air-interface correction functions. CONCLUSIONS EyeMC is a MC calculation system for ophthalmic brachytherapy based on a realistic and customizable eye-tumor model which includes the main eye structures with their real composition. Integrating this tool into a cloud computing environment allows to perform high-precision MC calculations of ocular plaque treatments in short times. The observed variability in eye anatomy among the selected cases justifies the use of patient-specific models.
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Affiliation(s)
- Héctor Miras Del Río
- Department of Medical Physics, Hospital Universitario Virgen Macarena, Seville, Spain
| | - Antonio Ortiz Lora
- Department of Medical Physics, Hospital Universitario Virgen Macarena, Seville, Spain
| | - Alejandro Bertolet Reina
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Dupere JM, Munro JJ, Medich DC. Shielded high dose rate ocular brachytherapy using Yb-169. Phys Med Biol 2021; 66. [PMID: 34010825 DOI: 10.1088/1361-6560/ac02d6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/19/2021] [Indexed: 11/12/2022]
Abstract
Purpose.We propose an approach for treating ocular melanoma using a new type of brachytherapy treatment device. This device couples Yb-169, a middle-energy high dose rate (HDR) brachytherapy source, with a gold shielded ring applicator to better conform radiation exposures to the tumor. In this study, we computationally test the dosimetric output of our proposed shielded ring applicator design using MCNP6 and validate it against an I-125 COMS plaque.Methods.The proposed Yb-169 ring applicator consists of an assembly of discrete sources delivered into an applicator with a conical collimated opening; this opening is tangent to the outside of the source tube. Using MCNP6, we simulated the dosimetric output of a ring of Yb-169 pellets placed within the collimator at various conical diameters and angles to demonstrate the dosimetric distribution for various prescription dose depths and target sizes using static intensity modulation.Results.Using various angles of collimation, the prescription dose was delivered to target apex depths of 3.5-8.0 mm into the eye covering target sizes ranging from 10 to 15 mm in diameter. This proposed device reduced the maximum absorbed dose to critical structures relative to I-125 by 5.2% to the posterior lens, 9.3% to the iris, 13.8% to the optic nerve, and 1.3% to the sclera.Conclusions.This proposed eye plaque design provides a more conformal dose distribution to the ocular tumor while minimizes dose to healthy ocular structures. In addition, the use of a middle-energy HDR brachytherapy source allows the use of a remote afterloader to expose the tumor after the plaque is sutured in place. This system is inherently safer and eliminates dose to the surgeon's hands.
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Affiliation(s)
- Justine M Dupere
- Worcester Polytechnic Institute, Worcester, MA 01609, United States of America
| | - John J Munro
- Montrose Technology Inc., North Andover, MA, 01845, United States of America
| | - David C Medich
- Worcester Polytechnic Institute, Worcester, MA 01609, United States of America
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Mao MH, Fan Y, Qiu R, Ren L, Hu A, Li JL, Han ZX. A Newly Designed Seed-Loading Device for Verifying the Safety of 125I Implants to the Canine Carotid Artery. Radiat Res 2021; 196:175-182. [PMID: 33979443 DOI: 10.1667/rade-21-00020.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/13/2021] [Indexed: 11/03/2022]
Abstract
A seed-loading device was designed and modeled using the Monte Carlo method to verify the biological effect of iodine-125 (125I) particles on blood vessels through animal experiments. The dose distribution characteristics of irradiated vessels were established by adjusting the design variables and geometry. The deviation between the actual value and the theoretical value was verified in vitro by the thermoluminescence dosimetry (TLD) method. After verification, the device was used to examine the biological effect of 125I irradiation of canine carotid arteries in two dogs (and one control dog) for 180 days. The hollow cylinder seed-loading device was constructed with an inner diameter of 0.5 cm and a length of 3.3 cm. When six seeds were loaded into a single layer, the source strength ratio of the intermediate layer to the edge layer was 0.7:1. When six layers of seeds were arranged at 0.45-cm intervals, the deviations between the maximum, minimum and mean energy fluence within 2.25 cm of the vessel wall were 2.19% and -4.12%, respectively, and -9% and 4%, respectively, when verified in vitro using TLD. The carotid arteries showed good tolerance to 0.56 kGy (range of 0.51-0.58 kGy) after 180 days of irradiation. In conclusion, this 125I seed-loading device overcomes the random distribution of seeds and lays an accurate radiophysical foundation for subsequent biological experiments. The preliminary results showed that the carotid artery has good tolerance to 0.56 kGy irradiation.
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Affiliation(s)
- Ming-Hui Mao
- Department of Oral and Maxillary Surgery, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100050, P.R. China
| | - Yi Fan
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.,National Clinical Research Center for Oral Diseases and National Engineering Laboratory for Digital and Material Technology of Stomatology and Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Rui Qiu
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, P.R. China.,Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, 100084, P.R. China
| | - Li Ren
- Nuctech Company Limited, Beijing, 100084, P.R. China
| | - Ankang Hu
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, P.R. China.,Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, 100084, P.R. China
| | - Jun-Li Li
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, P.R. China.,Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, 100084, P.R. China
| | - Zheng-Xue Han
- Department of Oral and Maxillary Surgery, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100050, P.R. China
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Development of GATE Monte Carlo Code for Simulation and Dosimetry of New I-125 Seeds in Eye Plaque Brachytherapy. Nucl Med Mol Imaging 2021; 55:86-95. [PMID: 33968275 DOI: 10.1007/s13139-020-00680-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 11/28/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022] Open
Abstract
Purpose Dose distributions are calculated by Monte Carlo (MC) simulations for two low-energy models 125I brachytherapy source-IrSeed-125 and IsoAid Advantage (model IAI-125A)-loaded in the 14-mm standardized plaque of the COMS during treatment of choroid melanoma. Methods In this study, at first, the radial dose function in water around 125I brachytherapy sources was calculated based on the recommendations of the Task Group No. 43 American Association of Physicists in Medicine (TG-43U1 APPM) using by GATE code. Then, brachytherapy dose distribution of a new model of the human eye was investigated for a 14-mm COMS eye plaque loaded with these sources with GATE Monte Carlo simulation. Results Results show that there are good agreements between simulation results of these sources and reporting measurements and simulations. Dosimetry results in the designed eye phantom for two types of iodine seeds show that the ratios of average dose of tumor to sclera, vitreous, and retina for IrSeed (IsoAid) source are 3.7 (3.7), 6.2 (6.1), and 6.3 (6.3), respectively, which represents the dose saving to healthy tissues. The maximum percentage differences between DVH curve of IsoAid and IrSeed seeds was about 8%. Conclusions Our simulation results show that although new model of the 125I brachytherapy source having a slightly larger dimension than IAI-125A, it can be used for eye melanoma treatment because the COMS eye plaque loaded with IrSeed-125 could produce similar results to the IsoAid seeds, which is applicable for clinical plaque brachytherapy for uveal melanoma.
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Hashemi S, Aghamiri MR, Kahani M, Jaberi R. Investigation of gold nanoparticle effects in brachytherapy by an electron emitter ophthalmic plaque. Int J Nanomedicine 2019; 14:4157-4165. [PMID: 31239674 PMCID: PMC6560204 DOI: 10.2147/ijn.s205814] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 05/04/2019] [Indexed: 12/17/2022] Open
Abstract
Background: During decades, all improvements and developments in radiation therapy technologies have been focused on its main goal: maximize the dose in the tumor and minimize it in surrounding normal tissues. Recently, scientists have some approaches to nanoparticles, especially gold nanoparticles (GNPs), for dose localization. Purpose: Herein, the effect of GNPs in combination with electron brachytherapy in a model of eye tumor has been investigated. Materials and methods: Monte Carlo simulation was utilized and a complete anatomical model of the eye, a tumor with 5 mm thick, and a type of Ruthenium-106 beta emitter ophthalmic plaque were simulated. Simulation results have been validated by a Plexiglas eye phantom and film dosimetry, experimentally. Results: The results showed using GNPs causes the dose amplification in 2 mm from the plaque surface which the higher concentration has the higher enhancement. At more distances, Dose Enhancement Factors (DEFs) have the negative amounts, so that total delivered dose to the tumor has decreased with increasing of Au concentrations and the dose of organ at risk like sclera has increased. Conclusion: Therefore, using of GNPs along with a 106Ru/106Rh ocular plaque, as an electron emitter source, is a good choice only for superficial lesions, and it is not recommended for deeper tumors due to the parameters of radiation treatment and delivered dose to the tissues.
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Affiliation(s)
- S Hashemi
- Radiation Medicine Engineering Department, Shahid Beheshti University, Tehran, Iran
| | - MR Aghamiri
- Radiation Medicine Engineering Department, Shahid Beheshti University, Tehran, Iran
| | - M Kahani
- Radiation Medicine Engineering Department, Shahid Beheshti University, Tehran, Iran
| | - R Jaberi
- Cancer Institute, Imam Khomeini Hospital, Tehran, Iran
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Ebrahimi-Khankook A, Vejdani-Noghreiyan A. Dosimetric comparison between realistic ocular model and other models for COMS plaque brachytherapy with 103Pd, 131Cs, and 125I radioisotopes. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2018; 57:265-275. [PMID: 29882078 DOI: 10.1007/s00411-018-0748-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
Nowadays, Monte Carlo calculations are commonly used for the evaluation of dose distributions and dose volume histograms in eye brachytherapy. However, currently available eye models have simple geometries, and main substructures of the eye are either not defined in details or not distinguished at all. In this work absorbed doses of eye substructures have been estimated for eye plaque brachytherapy using the most realistic eye model available, and compared with absorbed doses obtained with other available eye models. For this, a medium-sized tumour on the left sides of the right eye was considered. Dosimetry calculations were performed for four different eye models developed based on a literature review, and using a 12 mm Collaborative Ocular Melanoma Study plaque containing 131Cs, 103Pd, and 125I sources. Obtained results illustrate that the estimated doses received by different eye substructures strongly depend on the model used to represent the eye. It is shown here that using a non-realistic eye model leads to a wrong estimation of doses for some eye substructures. For example, dose differences of up to 35% were observed between the models proposed by Nogueira and co-workers and Yoriyaz and co-workers, while doses obtained by use of the models proposed by Lesperance and co-workers, and Behrens and co-workers differed up to 100 and 63% as compared to the situation when a realistic model was used, respectively. Moreover, comparing different radionuclides showed that the most uniform dose distribution in the considered tumour region was that from 131Cs, with a coefficient of variation of 33%. In addition, considering the realistic eye model, it was found that the radiosensitive region of the lens received more than the threshold dose of cataract induction (0.5 Gy), for all investigated radionuclides.
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Evaluation of dose enhancement in presence of gold nanoparticles in eye brachytherapy by 103Pd source. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:545-553. [DOI: 10.1007/s13246-017-0555-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 05/04/2017] [Indexed: 02/03/2023]
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Asadi S, Vaez-Zadeh M, Vahidian M, Marghchouei M, Masoudi SF. Ocular brachytherapy dosimetry for 103Pd and 125I in the presence of gold nanoparticles: a Monte Carlo study. J Appl Clin Med Phys 2016; 17:90-99. [PMID: 27167265 PMCID: PMC5690933 DOI: 10.1120/jacmp.v17i3.5945] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 12/28/2015] [Accepted: 12/15/2015] [Indexed: 12/17/2022] Open
Abstract
The aim of the present Monte Carlo study is to evaluate the variation of energy deposition in healthy tissues in the human eye which is irradiated by brachytherapy sources in comparison with the resultant dose increase in the gold nanoparticle (GNP)-loaded choroidal melanoma. The effects of these nanoparticles on normal tissues are compared between 103Pd and 125I as two ophthalmic brachytherapy sources. Dose distribution in the tumor and healthy tissues has been taken into account for both brachytherapy sources. Also, in certain points of the eye, the ratio of the absorbed dose by the normal tissue in the presence of GNPs to the absorbed dose by the same point in the absence of GNPs has been calculated. In addition, differences of the absorbed dose in the tumor observed in the comparison of simple water phantom and actual simulated human eye in presence of GNPs are also a matter of interest that have been considered in the present work. The difference between the eye globe and the water phantom is more obvious for 125I than that of the 103Pd when the ophthalmic dosimetry is done in the presence of GNPs. Whenever these nanoparticles are utilized in enhancing the absorbed dose by the tumor, the use of 125I brachytherapy source will greatly amplify the amount of dose enhancement factor (DEF) in the tumor site without inflicting much dam-age to healthy organs, when compared to the 103Pd source. For instance, in the concentration of 30 mg GNPs, the difference amongst the calculated DEF for 125I between these phantoms is 5.3%, while it is 2.45% for 103Pd. Furthermore, in Monte Carlo studies of eye brachytherapy, more precise definition of the eye phantom instead of a water phantom will become increasingly important when we use 125I as opposed to 103Pd.
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Rasouli FS, Farhad Masoudi S, Keshazare S, Jette D. Effect of elemental compositions on Monte Carlo dose calculations in proton therapy of eye tumors. Radiat Phys Chem Oxf Engl 1993 2015. [DOI: 10.1016/j.radphyschem.2015.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Asadi S, Vaez-zadeh M, Masoudi SF, Rahmani F, Knaup C, Meigooni AS. Gold nanoparticle-based brachytherapy enhancement in choroidal melanoma using a full Monte Carlo model of the human eye. J Appl Clin Med Phys 2015; 16:344–357. [PMID: 26699318 PMCID: PMC5690168 DOI: 10.1120/jacmp.v16i5.5568] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 04/15/2015] [Accepted: 04/08/2015] [Indexed: 12/20/2022] Open
Abstract
The effects of gold nanoparticles (GNPs) in 125I brachytherapy dose enhancement on choroidal melanoma are examined using the Monte Carlo simulation technique. Usually, Monte Carlo ophthalmic brachytherapy dosimetry is performed in a water phantom. However, here, the compositions of human eye have been considered instead of water. Both human eye and water phantoms have been simulated with MCNP5 code. These simulations were performed for a fully loaded 16 mm COMS eye plaque containing 13 125I seeds. The dose delivered to the tumor and normal tissues have been calculated in both phantoms with and without GNPs. Normally, the radiation therapy of cancer patients is designed to deliver a required dose to the tumor while sparing the surrounding normal tissues. However, as the normal and cancerous cells absorbed dose in an almost identical fashion, the normal tissue absorbed radiation dose during the treatment time. The use of GNPs in combination with radiotherapy in the treatment of tumor decreases the absorbed dose by normal tissues. The results indicate that the dose to the tumor in an eyeball implanted with COMS plaque increases with increasing GNPs concentration inside the target. Therefore, the required irradiation time for the tumors in the eye is decreased by adding the GNPs prior to treatment. As a result, the dose to normal tissues decreases when the irradiation time is reduced. Furthermore, a comparison between the simulated data in an eye phantom made of water and eye phantom made of human eye composition, in the presence of GNPs, shows the significance of utilizing the composition of eye in ophthalmic brachytherapy dosimetry Also, defining the eye composition instead of water leads to more accurate calculations of GNPs radiation effects in ophthalmic brachytherapy dosimetry.
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Findlay RP. Induced electric fields in the MAXWEL surface-based human model from exposure to external low frequency electric fields. RADIATION PROTECTION DOSIMETRY 2014; 162:244-253. [PMID: 24218644 DOI: 10.1093/rpd/nct281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This work presents calculations of internal induced electric fields in the anatomically realistic surface-based model of the male human body, MAXWEL, from exposure to external low frequency electric fields under grounded and isolated conditions. The maximum 99th percentile induced electric fields calculated in the MAXWEL central nervous system were 3.49 (grounded) and 1.54 (isolated) mV m(-1) per kV m(-1) at 50 Hz. The application of 2, 1 and 0.5 mm resolution voxel models derived from the surface-based version to the calculations of induced electric fields is described. 2 mm and 1 mm resolution maximum 99th percentile induced electric field values calculated in selected tissues of the eye at 50 Hz were within 30 % of those calculated at 0.5 mm resolution. The calculated electric field values in MAXWEL were compared with values from the male model NORMAN and female model NAOMI. The maximum 99th percentile value for NAOMI, calculated by Dimbylow in bone, was 49.4 mV m(-1) per kV m(-1) at 50 Hz under grounded conditions. The corresponding value calculated in MAXWEL was 15.7 mV m(-1) per kV m(-1), considerably lower due to anatomical differences between the male and female models.
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Asadi S, Masoudi SF, Shahriari M. The effects of variations in the density and composition of eye materials on ophthalmic brachytherapy dosimetry. Med Dosim 2011; 37:1-4. [PMID: 21723111 DOI: 10.1016/j.meddos.2010.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Revised: 11/12/2010] [Accepted: 12/08/2010] [Indexed: 11/30/2022]
Abstract
In ophthalmic brachytherapy dosimetry, it is common to consider the water phantom as human eye anatomy. However, for better clinical analysis, there is a need for the dose determination in different parts of the eye. In this work, a full human eye is simulated with MCNP-4C code by considering all parts of the eye, i.e., the lens, cornea, retina, choroid, sclera, anterior chamber, optic nerve, and bulk of the eye comprising vitreous body and tumor. The average dose in different parts of this full model of the human eye is determined and the results are compared with the dose calculated in water phantom. The central axes depth dose and the dose in whole of the tumor for these 2 simulated eye models are calculated as well, and the results are compared.
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Affiliation(s)
- Somayeh Asadi
- Department of Physics, K.N. Toosi University of Technology, Tehran, Iran
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Dimbylow P. Spherical polar co-ordinate calculations of induced fields in the retina and head for applied magnetic fields at 50 Hz. Phys Med Biol 2011; 56:4597-611. [DOI: 10.1088/0031-9155/56/14/023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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A boundary element model for investigating the effects of eye tumor on the temperature distribution inside the human eye. Comput Biol Med 2009; 39:667-77. [DOI: 10.1016/j.compbiomed.2009.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 03/08/2009] [Accepted: 04/29/2009] [Indexed: 11/15/2022]
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