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Entezam A, Fielding A, Bradley D, Fontanarosa D. Absorbed dose calculation for a realistic CT-derived mouse phantom irradiated with a standard Cs-137 cell irradiator using a Monte Carlo method. PLoS One 2023; 18:e0280765. [PMID: 36730280 PMCID: PMC9928120 DOI: 10.1371/journal.pone.0280765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 01/07/2023] [Indexed: 02/03/2023] Open
Abstract
Computed tomography (CT) derived Monte Carlo (MC) phantoms allow dose determination within small animal models that is not feasible with in-vivo dosimetry. The aim of this study was to develop a CT-derived MC phantom generated from a mouse with a xenograft tumour that could then be used to calculate both the dose heterogeneity in the tumour volume and out of field scattered dose for pre-clinical small animal irradiation experiments. A BEAMnrc Monte-Carlo model has been built of our irradiation system that comprises a lead collimator with a 1 cm diameter aperture fitted to a Cs-137 gamma irradiator. The MC model of the irradiation system was validated by comparing the calculated dose results with dosimetric film measurement in a polymethyl methacrylate (PMMA) phantom using a 1D gamma-index analysis. Dose distributions in the MC mouse phantom were calculated and visualized on the CT-image data. Dose volume histograms (DVHs) were generated for the tumour and organs at risk (OARs). The effect of the xenographic tumour volume on the scattered out of field dose was also investigated. The defined gamma index analysis criteria were met, indicating that our MC simulation is a valid model for MC mouse phantom dose calculations. MC dose calculations showed a maximum out of field dose to the mouse of 7% of Dmax. Absorbed dose to the tumour varies in the range 60%-100% of Dmax. DVH analysis demonstrated that tumour received an inhomogeneous dose of 12 Gy-20 Gy (for 20 Gy prescribed dose) while out of field doses to all OARs were minimized (1.29 Gy-1.38 Gy). Variation of the xenographic tumour volume exhibited no significant effect on the out of field scattered dose to OARs. The CT derived MC mouse model presented here is a useful tool for tumour dose verifications as well as investigating the doses to normal tissue (in out of field) for preclinical radiobiological research.
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Affiliation(s)
- Amir Entezam
- School of Clinical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, Australia
- Translational Research Institute, The University of Queensland, Brisbane, QLD, Australia
- * E-mail:
| | - Andrew Fielding
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - David Bradley
- Centre for Applied Physics and Radiation Technologies, Sunway University, PJ, Malaysia
- Department of Physics, University of Surrey, Guildford, United Kingdom
| | - Davide Fontanarosa
- School of Clinical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, Australia
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Entezam A, Fielding A, Moi D, Bradley D, Ratnayake G, Sim L, Kralik C, Fontanarosa D. Investigation of scattered dose in a mouse phantom model for pre-clinical dosimetry studies. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wong JHD, Zaili Z, Abdul Malik R, Bustam AZ, Saad M, Jamaris S, Mosiun JA, Mohd Taib NA, Ung NM, See M. Evaluation of skin dose and skin toxicity in patients undergoing intraoperative radiotherapy for early breast cancer. J Appl Clin Med Phys 2021; 22:139-147. [PMID: 34254425 PMCID: PMC8364274 DOI: 10.1002/acm2.13338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
PURPOSE This study aims to evaluate in vivo skin dose delivered by intraoperative radiotherapy (IORT) and determine the factors associated with an increased risk of radiation-induced skin toxicity. METHODOLOGY A total of 21 breast cancer patients who underwent breast-conserving surgery and IORT, either as IORT alone or IORT boost plus external beam radiotherapy (EBRT), were recruited in this prospective study. EBT3 film was calibrated in water and used to measure skin dose during IORT at concentric circles of 5 mm and 40 mm away from the applicator. For patients who also had EBRT, the maximum skin dose was estimated using the radiotherapy treatment planning system. Mid-term skin toxicities were evaluated at 3 and 6 months post-IORT. RESULTS The average skin dose at 5 mm and 40 mm away from the applicator was 3.07 ± 0.82 Gy and 0.99 ± 0.28 Gy, respectively. Patients treated with IORT boost plus EBRT received an additional skin dose of 41.07 ± 1.57 Gy from the EBRT component. At 3 months post-IORT, 86% of patients showed no evidence of skin toxicity. However, the number of patients suffering from skin toxicity increased from 15% to 38% at 6 months post-IORT. We found no association between the IORT alone or with the IORT boost plus EBRT and skin toxicity. Older age was associated with increased risk of skin toxicities. A mathematical model was derived to predict skin dose. CONCLUSION EBT3 film is a suitable dosimeter for in vivo skin dosimetry in IORT, providing patient-specific skin doses. Both IORT alone and IORT boost techniques resulted in similar skin toxicity rates.
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Affiliation(s)
- Jeannie Hsiu Ding Wong
- Department of Biomedical ImagingFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Zainor Zaili
- Department of Biomedical ImagingFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Rozita Abdul Malik
- Clinical Oncology UnitFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Anita Zarina Bustam
- Clinical Oncology UnitFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Marniza Saad
- Clinical Oncology UnitFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Suniza Jamaris
- Breast Surgery UnitDepartment of Medicine, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
- Department of Surgery, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Joanne Aisha Mosiun
- Department of Surgery, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Nur Aishah Mohd Taib
- Breast Surgery UnitDepartment of Medicine, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Ngie Min Ung
- Clinical Oncology UnitFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Mee‐Hoong See
- Breast Surgery UnitDepartment of Medicine, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
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Fontanarosa D, Benitez J, Talkhani S, Fielding A, Entezam A, Trapp J, Moi D, Biasi G, Petasecca M, Mazzieri R. A novel add-on collimator for preclinical radiotherapy applications using a standard cell irradiator: design, construction, and validation. Med Phys 2020; 47:2461-2471. [PMID: 32133649 DOI: 10.1002/mp.14110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/07/2020] [Accepted: 02/25/2020] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Preclinical radiotherapy applications require dedicated irradiation systems which are expensive and not widely available. In this work, a clinical dual source 137 Cs cell irradiator was adapted to deliver 1-cm diameter preclinical treatment beams using a lead and stainless steel custom-made collimator to treat one or two mice at a time. METHODS The dosimetric characteristics of all the different components of the system (including collimator, phantoms, and radiation sources) have been simulated with EGSnrc Monte Carlo methods. The collimator was constructed based on these simulations and the calculated results were verified against dosimetric measurements with MOSKin detectors, GAFchromic films, and dosimetric gels. RESULTS The comparisons showed an agreement, in terms of full width half maximum values, between the simulated and the measured dose cross profiles at the midline within 4% for both gel dosimetry and GAFchromic films. Out of beam dose, measured in air at the collimator midplane with MOSFET detectors was between 6% and 10% of the beam axis dose. The dimensions of the beam are constant along the vertical axis of the collimator and also the simulated and measured Percentage Depth Dose (PDD) curves show an agreement within 1%. CONCLUSIONS The collimator design developed in this work allows the creation of a beam with the necessary characteristics for ablative radiotherapy treatments on small animals using a standard clinical cell irradiator. This collimator design will make advanced preclinical studies with ablative beams possible for all those institutions which do not have collimated preclinical irradiators available.
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Affiliation(s)
- Davide Fontanarosa
- School of Clinical Sciences, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Jessica Benitez
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia.,Chemistry Physics Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Sana Talkhani
- Chemistry Physics Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Andrew Fielding
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia.,Chemistry Physics Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Amir Entezam
- School of Clinical Sciences, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Jamie Trapp
- Chemistry Physics Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Davide Moi
- Diamantina Institute, Translational Research Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Giordano Biasi
- School of Physics, Faculty of Engineering and Information Sciences, Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Marco Petasecca
- School of Physics, Faculty of Engineering and Information Sciences, Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Roberta Mazzieri
- Diamantina Institute, Translational Research Institute, The University of Queensland, Woolloongabba, QLD, 4102, Australia
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Jamalludin Z, Jong WL, Abdul Malik R, Rosenfeld A, Ung NM. Characterization of MOSkin detector for in vivo dose verification during Cobalt-60 high dose-rate intracavitary brachytherapy. Phys Med 2019; 58:1-7. [PMID: 30824140 DOI: 10.1016/j.ejmp.2019.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 12/12/2018] [Accepted: 01/08/2019] [Indexed: 10/27/2022] Open
Abstract
In vivo dosimetry in high dose-rate (HDR) intracavitary brachytherapy (ICBT) is important for assessing the true dose received by surrounding organs at risk during treatment. It also serves as part of the treatment delivery quality assurance and verification program with the use of a suitable dosimeter. Such a dosimeter should be characterized under brachytherapy conditions before clinical application to ensure the accuracy of in vivo measurement. In this study, a MOSFET-based detector, MOSkin, was calibrated and characterized under HDR Cobalt-60 (Co-60) brachytherapy source. MOSkin possessed the major advantages of having small physical and dosimetric sizes of 4.8 × 10-6 mm3 with the ability to provide real-time measurements. Using solid water and polymethyl methacrylate (PMMA) phantom, the detectors' reproducibility, linearity, angular and distance dependency was tested for its suitability as an in vivo detector. Correction factors to account for differences in depth measurements were determined. The MOSkin detector showed a reliable response when tested under Co-60 brachytherapy range of doses with an excellent linearity of R2 = 0.9997 and acceptable reproducibility. A phantom verification study was also conducted to verify the differences between MOSkin responses and treatment planning (TPS) calculated doses. By taking into account several correction factors, deviations ranging between 0.01 and 0.4 Gy were found between MOSkin measured and TPS doses at measurement distance of 20-55 mm. The use of MOSkin as the dosimeter of choice for in vivo dosimetry under Co-60 brachytherapy condition is feasible.
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Affiliation(s)
- Zulaikha Jamalludin
- Department of Clinical Oncology, University of Malaya Medical Centre, Kuala Lumpur, Malaysia; Medical Physics Unit, University of Malaya Medical Centre, Kuala Lumpur, Malaysia
| | - Wei Loong Jong
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Rozita Abdul Malik
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Ngie Min Ung
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Sun W, Wang B, Qiu B, Liang J, Xie W, Deng X, Qi Z. Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters. Oncotarget 2017; 8:20179-20186. [PMID: 28423624 PMCID: PMC5386753 DOI: 10.18632/oncotarget.15555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/23/2017] [Indexed: 11/25/2022] Open
Abstract
Objective: To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Materials and Methods: Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. Results: The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Conclusions: Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification.
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Affiliation(s)
- Wenzhao Sun
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Bin Wang
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Bo Qiu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Jian Liang
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Weihao Xie
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Xiaowu Deng
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
| | - Zhenyu Qi
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou 510060, China
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Semiconductor real-time quality assurance dosimetry in brachytherapy. Brachytherapy 2017; 17:133-145. [PMID: 28964727 DOI: 10.1016/j.brachy.2017.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 11/23/2022]
Abstract
With the increase in complexity of brachytherapy treatments, there has been a demand for the development of sophisticated devices for delivery verification. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has demonstrated the applicability of semiconductor devices to provide cost-effective real-time quality assurance for a wide range of brachytherapy treatment modalities. Semiconductor devices have shown great promise to the future of pretreatment and in vivo quality assurance in a wide range of brachytherapy treatments, from high-dose-rate (HDR) prostate procedures to eye plaque treatments. The aim of this article is to give an insight into several semiconductor-based dosimetry instruments developed by the CMRP. Applications of these instruments are provided for breast and rectal wall in vivo dosimetry in HDR brachytherapy, urethral in vivo dosimetry in prostate low-dose-rate (LDR) brachytherapy, quality assurance of HDR brachytherapy afterloaders, HDR pretreatment plan verification, and real-time verification of LDR and HDR source dwell positions.
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Safari MJ, Wong JHD, Jong WL, Thorpe N, Cutajar D, Rosenfeld A, Ng KH. Influence of exposure and geometric parameters on absorbed doses associated with common neuro-interventional procedures. Phys Med 2017; 35:66-72. [DOI: 10.1016/j.ejmp.2017.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 11/28/2022] Open
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Thorpe NK, Cutajar D, Lian C, Pitney M, Friedman D, Perevertaylo V, Rosenfeld A. A comparison of entrance skin dose delivered by clinical angiographic c-arms using the real-time dosimeter: the MOSkin. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:423-30. [DOI: 10.1007/s13246-016-0435-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 03/06/2016] [Indexed: 10/21/2022]
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Real-time eye lens dose monitoring during cerebral angiography procedures. Eur Radiol 2015; 26:79-86. [DOI: 10.1007/s00330-015-3818-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/30/2015] [Accepted: 04/22/2015] [Indexed: 10/23/2022]
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