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Seo J, Lee H, Hwan Ahn S, Yoon M. Feasibility study of a scintillation sheet-based detector for fluence monitoring during external photon beam radiotherapy. Phys Med 2023; 112:102628. [PMID: 37354806 DOI: 10.1016/j.ejmp.2023.102628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/24/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023] Open
Abstract
PURPOSE This study evaluated the properties of a scintillation sheet-based dosimetry system for beam monitoring with high spatial resolution, including the effects of this system on the treatment beam. The dosimetric characteristics and feasibility of this system for clinical use were also evaluated. METHODS The effects of the dosimetry system on the beam were evaluated by measuring the percentage depth doses, dose profiles, and transmission factors. Fifteen treatment plans were created, and the influence of the dosimetry system on these clinical treatment plans was evaluated. The performance of the system was assessed by determining signal linearity, dose rate dependence, and reproducibility. The feasibility of the system for clinical use was evaluated by comparing intensity distributions with reference intensity distributions verified by quality assurance. RESULTS The spatial resolution of the dosimetry system was found to be 0.43 mm/pixel when projected to the isocenter plane. The dosimetry system attenuated the intensity of 6 MV beams by about 1.1%, without affecting the percentage depth doses and dose profiles. The response of the dosimetry system was linear, independent of the dose rate used in the clinic, and reproducible. Comparison of intensity distributions of evaluation treatment fields with reference intensity distributions showed that the 1%/1 mm average gamma passing rate was 99.6%. CONCLUSIONS The dosimetry system did not significantly alter the beam characteristics, indicating that the system could be implemented by using only a transmission factor. The dosimetry system is clinically suitable for monitoring treatment beam delivery with higher spatial resolution than other transmission detectors.
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Affiliation(s)
- Jaehyeon Seo
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
| | - Hyunho Lee
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea
| | - Sung Hwan Ahn
- Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea.
| | - Myonggeun Yoon
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; FieldCure Ltd, Seoul, Republic of Korea.
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Dai G, Xu X, Wu X, Lei X, Wei X, Li Z, Xiao Q, Zhong R, Bai S. Application of 3D-print silica bolus for nasal NK/T-cell lymphoma radiation therapy. JOURNAL OF RADIATION RESEARCH 2020; 61:920-928. [PMID: 32960262 PMCID: PMC7674672 DOI: 10.1093/jrr/rraa084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/28/2020] [Accepted: 06/23/2020] [Indexed: 02/05/2023]
Abstract
The aim of the study was to evaluate the clinical feasibility of a 3D-print silica bolus for nasal NK/T-cell lymphoma radiation therapy. Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were designed using an anthropomorphic head phantom with a 3D-print silica bolus and other kinds of bolus used clinically, and the surface dose was measured by a metal oxide semiconductor field-effect transistor (MOSFET) dosimeter. Four nasal NK/T patients with or without 3D-print silica bolus were treated and the nose surface dose was measured using a MOSFET dosimeter during the first treatment. Plans for the anthropomorphic head phantom with 3D-print bolus have more uniform dose and higher conformity of the planning target volume (PTV) compared to other boluses; the homogeneity index (HI) and conformity index (CI) of the VMAT plan were 0.0589 and 0.7022, respectively, and the HI and CI of the IMRT plan were 0.0550 and 0.7324, respectively. The MOSFET measurement results showed that the surface dose of the phantom with 3D-print bolus was >180 cGy, and that of patients with 3D-print bolus was higher than patients without bolus. The air gap volume between the 3D-print bolus and the surface of patients was <0.3 cc. The 3D-print silica bolus fitted well on the patient’s skin, effectively reducing air gaps between bolus and patient surface. Meanwhile, the 3D-print silica bolus provided patients with higher individuation, and improved the conformity and uniformity of the PTV compared to other kinds of boluses.
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Affiliation(s)
- Guyu Dai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xin Xu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University/Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
| | - Xiaohong Wu
- Department of Oncology, The affiliated Hospital of Panzhihua University, Panzhihua, China
| | - Xiaolin Lei
- Department of Oncology, The affiliated Hospital of Panzhihua University, Panzhihua, China
| | - Xing Wei
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University/Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
| | - Zhibin Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Qing Xiao
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Renming Zhong
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Sen Bai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
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Wang X, Li G, Zhao J, Song Y, Xiao J, Bai S. Verification of eye lens dose in IMRT by MOSFET measurement. Med Dosim 2019; 44:107-110. [DOI: 10.1016/j.meddos.2018.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 11/17/2022]
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Al-Rahbi ZS, Cutajar DL, Metcalfe P, Rosenfeld AB. Dosimetric effects of brass mesh bolus on skin dose and dose at depth for postmastectomy chest wall irradiation. Phys Med 2018; 54:84-93. [DOI: 10.1016/j.ejmp.2018.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/21/2018] [Indexed: 11/28/2022] Open
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Jong W, Ung N, Tiong A, Rosenfeld A, Wong J. Characterisation of a MOSFET-based detector for dose measurement under megavoltage electron beam radiotherapy. Radiat Phys Chem Oxf Engl 1993 2018. [DOI: 10.1016/j.radphyschem.2017.11.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dosimetric evaluation near lung and soft tissue interface region during respiratory-gated and non-gated radiotherapy: A moving phantom study. Phys Med 2017; 42:39-46. [DOI: 10.1016/j.ejmp.2017.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/27/2017] [Accepted: 08/23/2017] [Indexed: 12/25/2022] Open
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Vicoroski N, Espinoza A, Duncan M, Oborn BM, Carolan M, Metcalfe P, Menichelli D, Perevertaylo VL, Lerch MLF, Rosenfeld AB, Petasecca M. Development of a silicon diode detector for skin dosimetry in radiotherapy. Med Phys 2017; 44:5402-5412. [DOI: 10.1002/mp.12469] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/14/2017] [Accepted: 06/28/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Nikolina Vicoroski
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Anthony Espinoza
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Mitchell Duncan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Bradley M. Oborn
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Martin Carolan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | | | | | - Michael L. F. Lerch
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Anatoly B. Rosenfeld
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
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Jong WL, Ung NM, Vannyat A, Jamalludin Z, Rosenfeld A, Wong JHD. “Edge-on” MOSkin detector for stereotactic beam measurement and verification. Phys Med 2017; 33:127-135. [DOI: 10.1016/j.ejmp.2016.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/16/2016] [Accepted: 12/29/2016] [Indexed: 11/25/2022] Open
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In vivo skin dose measurement using MOSkin detectors in tangential breast radiotherapy. Phys Med 2016; 32:1466-1474. [PMID: 27842982 DOI: 10.1016/j.ejmp.2016.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study is to measure patient skin dose in tangential breast radiotherapy. Treatment planning dose calculation algorithm such as Pencil Beam Convolution (PBC) and in vivo dosimetry techniques such as radiochromic film can be used to accurately monitor radiation doses at tissue depths, but they are inaccurate for skin dose measurement. A MOSFET-based (MOSkin) detector was used to measure skin dose in this study. Tangential breast radiotherapies ("bolus" and "no bolus") were simulated on an anthropomorphic phantom and the skin doses were measured. Skin doses were also measured in 13 patients undergoing each of the techniques. In the patient study, the EBT2 measurements and PBC calculation tended to over-estimate the skin dose compared with the MOSkin detector (p<0.05) in the "no bolus radiotherapy". No significant differences were observed in the "bolus radiotherapy" (p>0.05). The results from patients were similar to that of the phantom study. This shows that the EBT2 measurement and PBC calculation, while able to predict accurate doses at tissue depths, are inaccurate in predicting doses at build-up regions. The clinical application of the MOSkin detectors showed that the average total skin doses received by patients were 1662±129cGy (medial) and 1893±199cGy (lateral) during "no bolus radiotherapy". The average total skin doses were 4030±72cGy (medial) and 4004±91cGy (lateral) for "bolus radiotherapy". In some cases, patient skin doses were shown to exceed the dose toxicity level for skin erythema. Hence, a suitable device for in vivo dosimetry is necessary to accurately determine skin dose.
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Fournier P, Cornelius I, Donzelli M, Requardt H, Nemoz C, Petasecca M, Bräuer-Krisch E, Rosenfeld A, Lerch M. X-Tream quality assurance in synchrotron X-ray microbeam radiation therapy. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:1180-1190. [PMID: 27577773 DOI: 10.1107/s1600577516009322] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
Microbeam radiation therapy (MRT) is a novel irradiation technique for brain tumours treatment currently under development at the European Synchrotron Radiation Facility in Grenoble, France. The technique is based on the spatial fractionation of a highly brilliant synchrotron X-ray beam into an array of microbeams using a multi-slit collimator (MSC). After promising pre-clinical results, veterinary trials have recently commenced requiring the need for dedicated quality assurance (QA) procedures. The quality of MRT treatment demands reproducible and precise spatial fractionation of the incoming synchrotron beam. The intensity profile of the microbeams must also be quickly and quantitatively characterized prior to each treatment for comparison with that used for input to the dose-planning calculations. The Centre for Medical Radiation Physics (University of Wollongong, Australia) has developed an X-ray treatment monitoring system (X-Tream) which incorporates a high-spatial-resolution silicon strip detector (SSD) specifically designed for MRT. In-air measurements of the horizontal profile of the intrinsic microbeam X-ray field in order to determine the relative intensity of each microbeam are presented, and the alignment of the MSC is also assessed. The results show that the SSD is able to resolve individual microbeams which therefore provides invaluable QA of the horizontal field size and microbeam number and shape. They also demonstrate that the SSD used in the X-Tream system is very sensitive to any small misalignment of the MSC. In order to allow as rapid QA as possible, a fast alignment procedure of the SSD based on X-ray imaging with a low-intensity low-energy beam has been developed and is presented in this publication.
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Affiliation(s)
- Pauline Fournier
- Centre for Medical Radiation Physics, University of Wollongong, Australia
| | - Iwan Cornelius
- Centre for Medical Radiation Physics, University of Wollongong, Australia
| | | | | | | | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, Australia
| | | | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Australia
| | - Michael Lerch
- Centre for Medical Radiation Physics, University of Wollongong, Australia
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Safari MJ, Wong JHD, Ng KH, Jong WL, Cutajar DL, Rosenfeld AB. Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures. Med Phys 2016; 42:2550-8. [PMID: 25979047 DOI: 10.1118/1.4918576] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. METHODS The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. RESULTS The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (± 1%), field size (± 1%), frame rate (± 3%), or beam energy (± 5%). The detector angular dependence was within ± 5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ± 3%. CONCLUSIONS The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.
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Affiliation(s)
- M J Safari
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - J H D Wong
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - K H Ng
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - W L Jong
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - D L Cutajar
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - A B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
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Alrowaili ZA, Lerch MLF, Petasecca M, Carolan MG, Metcalfe PE, Rosenfeld AB. Beam perturbation characteristics of a 2D transmission silicon diode array, Magic Plate. J Appl Clin Med Phys 2016; 17:85-98. [PMID: 27074475 PMCID: PMC5874939 DOI: 10.1120/jacmp.v17i2.5932] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/11/2015] [Accepted: 12/01/2015] [Indexed: 11/23/2022] Open
Abstract
The main objective of this study is to demonstrate the performance characteristics of the Magic Plate (MP) system when operated upstream of the patient in transmission mode (MPTM). The MPTM is an essential component of a real‐time QA system designed for operation during radiotherapy treatment. Of particular interest is a quantitative study into the influence of the MP on the radiation beam quality at several field sizes and linear accelerator potential differences. The impact is measured through beam perturbation effects such as changes in the skin dose and/or percentage depth dose (PDD) (both in and out of field). The MP was placed in the block tray of a Varian linac head operated at 6, 10 and 18 MV beam energy. To optimize the MPTM operational setup, two conditions were investigated and each setup was compared to the case where no MP is positioned in place (i.e., open field): (i) MPTM alone and (ii) MPTM with a thin passive contamination electron filter. The in‐field and out‐of‐field surface doses of a solid water phantom were investigated for both setups using a Markus plane parallel (Model N23343) and Attix parallel‐plate, MRI model 449 ionization chambers. In addition, the effect on the 2D dose distribution measured by the Delta4 QA system was also investigated. The transmission factor for both of these MPTM setups in the central axis was also investigated using a Farmer ionization chamber (Model 2571A) and an Attix ionization chamber. Measurements were performed for different irradiation field sizes of 5×5 cm2 and 10×10 cm2. The change in the surface dose relative to dmax was measured to be less than 0.5% for the 6 MV, 10 MV, and 18 MV energy beams. Transmission factors measured for both set ups (i & ii above) with 6 MV, 10 MV, and 18 MV at a depth of dmax and a depth of 10 cm were all within 1.6% of open field. The impact of both the bare MPTM and the MPTM with 1 mm buildup on 3D dose distribution in comparison to the open field investigated using the Delta4 system and both the MPTM versions passed standard clinical gamma analysis criteria. Two MPTM operational setups were studied and presented in this article. The results indicate that both versions may be suitable for the new real‐time megavoltage photon treatment delivery QA system under development. However, the bare MPTM appears to be slightly better suited of the two MP versions, as it minimally perturbs the radiation field and does not lead to any significant increase in skin dose to the patient. PACS number(s): 87.50.up, 87.53.Bn, 87.55.N, 87.55.Qr, 87.56.Fc.
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Alhakeem EA, AlShaikh S, Rosenfeld AB, Zavgorodni SF. Comparative evaluation of modern dosimetry techniques near low- and high-density heterogeneities. J Appl Clin Med Phys 2015; 16:142–158. [PMID: 26699322 PMCID: PMC5690181 DOI: 10.1120/jacmp.v16i5.5589] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/19/2015] [Accepted: 05/18/2015] [Indexed: 12/13/2022] Open
Abstract
The purpose of this study is to compare performance of several dosimetric methods in heterogeneous phantoms irradiated by 6 and 18 MV beams. Monte Carlo (MC) calculations were used, along with two versions of Acuros XB, anisotropic analytical algorithm (AAA), EBT2 film, and MOSkin dosimeters. Percent depth doses (PDD) were calculated and measured in three heterogeneous phantoms. The first two phantoms were a 30×30×30 cm3 solid‐water slab that had an air‐gap of 20×2.5×2.35 cm3. The third phantom consisted of 30×30×5 cm3 solid water slabs, two 30×30×5 cm3 slabs of lung, and one 30×30×1 cm3 solid water slab. Acuros XB, AAA, and MC calculations were within 1% in the regions with particle equilibrium. At media interfaces and buildup regions, differences between Acuros XB and MC were in the range of +4.4% to −12.8%. MOSkin and EBT2 measurements agreed to MC calculations within ∼2.5%, except for the first centimeter of buildup where differences of 4.5% were observed. AAA did not predict the backscatter dose from the high‐density heterogeneity. For the third, multilayer lung phantom, 6 MV beam PDDs calculated by all TPS algorithms were within 2% of MC. 18 MV PDDs calculated by two versions of Acuros XB and AAA differed from MC by up to 2.8%, 3.2%, and 6.8%, respectively. MOSkin and EBT2 each differed from MC by up to 2.9% and 2.5% for the 6 MV, and by −3.1% and ∼2% for the 18 MV beams. All dosimetric techniques, except AAA, agreed within 3% in the regions with particle equilibrium. Differences between the dosimetric techniques were larger for the 18 MV than the 6 MV beam. MOSkin and EBT2 measurements were in a better agreement with MC than Acuros XB calculations at the interfaces, and they were in a better agreement to each other than to MC. The latter is due to their thinner detection layers compared to MC voxel sizes. PACS numbers: 87.55.K‐, 87.55.kd, 87.55.km, 87.53.Bn, 87.55.k
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Affiliation(s)
- Eyad A Alhakeem
- University of Victoria, British Columbia Cancer Agency-Vancouver Island Centre; Ministry of Education.
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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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A very-low-cost dosimeter based on the off-the-shelf CD4007 MOSFET array for in vivo radiotherapy applications. RADIAT MEAS 2015. [DOI: 10.1016/j.radmeas.2015.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Luo GW, Qi ZY, Deng XW, Rosenfeld A. Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry. Med Phys 2014; 41:051710. [PMID: 24784376 DOI: 10.1118/1.4871619] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters for in vivo intensity modulated radiation therapy (IMRT) dosimetry. METHODS Several MOSFETs were irradiated at d(max) using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. RESULTS More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. CONCLUSIONS Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic.
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Affiliation(s)
- Guang-Wen Luo
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center and State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, China
| | - Zhen-Yu Qi
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center and State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, China
| | - Xiao-Wu Deng
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center and State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, China
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
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Jong WL, Wong JHD, Ung NM, Ng KH, Ho GF, Cutajar DL, Rosenfeld AB. Characterization of MOSkin detector for in vivo skin dose measurement during megavoltage radiotherapy. J Appl Clin Med Phys 2014; 15:4869. [PMID: 25207573 PMCID: PMC5711095 DOI: 10.1120/jacmp.v15i5.4869] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 05/19/2014] [Accepted: 05/14/2014] [Indexed: 11/25/2022] Open
Abstract
In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET‐based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real‐time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry. PACS number: 87.55.Qr
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Affiliation(s)
- Wei Loong Jong
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya.
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Park JM, Lee J, Kim HS, Ye SJ, Kim JI. Development of an applicator for eye lens dosimetry during radiotherapy. Br J Radiol 2014; 87:20140311. [PMID: 25111733 DOI: 10.1259/bjr.20140311] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE To develop an applicator for in vivo measurements of lens dose during radiotherapy. METHODS A contact lens-shaped applicator made of acrylic was developed for in vivo measurements of lens dose. This lens applicator allows the insertion of commercially available metal oxide semiconductor field effect transistors (MOSFETs) dosemeters. CT images of an anthropomorphic phantom with and without the applicator were acquired. Ten volumetric modulated arc therapy plans each for the brain and the head and neck cancer were generated and delivered to an anthropomorphic phantom. The differences between the measured and the calculated doses at the lens applicator, as well as the differences between the measured and the calculated doses at the surface of the eyelid were acquired. RESULTS The average difference between the measured and the calculated doses with the applicator was 3.1 ± 1.8 cGy with a micro MOSFET and 2.8 ± 1.3 cGy with a standard MOSFET. The average difference without the lens applicator was 4.8 ± 5.2 cGy with the micro MOSFET and 5.7 ± 6.5 cGy with the standard MOSFET. The maximum difference with the micro MOSFET was 10.5 cGy with the applicator and 21.1 cGy without the applicator. For the standard MOSFET, it was 6.8 cGy with the applicator and 27.6 cGy without the applicator. CONCLUSION The lens applicator allowed reduction of the differences between the calculated and the measured doses during in vivo measurement for the lens compared with in vivo measurement at the surface of the eyelid. ADVANCES IN KNOWLEDGE By using an applicator for in vivo dosimetry of the eye lens, it was possible to reduce the measurement uncertainty.
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Affiliation(s)
- J M Park
- 1 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
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Pejovic S, Bosnjakovic P, Ciraj-Bjelac O, Pejovic MM. Characteristics of a pMOSFET suitable for use in radiotherapy. Appl Radiat Isot 2013; 77:44-9. [DOI: 10.1016/j.apradiso.2013.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 01/30/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
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Mijnheer B, Beddar S, Izewska J, Reft C. In vivo
dosimetry in external beam radiotherapy. Med Phys 2013; 40:070903. [DOI: 10.1118/1.4811216] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Guidelli EJ, Ramos AP, Zaniquelli MED, Nicolucci P, Baffa O. Synthesis and characterization of gold/alanine nanocomposites with potential properties for medical application as radiation sensors. ACS APPLIED MATERIALS & INTERFACES 2012; 4:5844-51. [PMID: 23067227 DOI: 10.1021/am3014899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Radiation dose assessment is essential for several medical treatments and diagnostic procedures. In this context, nanotechnology has been used in the development of improved radiation sensors, with higher sensitivity as well as smaller sizes and energy dependence. This paper deals with the synthesis and characterization of gold/alanine nanocomposites with varying mass percentage of gold, for application as radiation sensors. Alanine is an excellent stabilizing agent for gold nanoparticles because the size of the nanoparticles does not augment with increasing mass percentage of gold, as evidenced by UV-vis spectroscopy, dynamic light scattering, and transmission electron microscopy. X-ray diffraction patterns suggest that the alanine crystalline orientation undergoes alterations upon the addition of gold nanoparticles. Fourier transform infrared spectroscopy indicates that there is interaction between the gold nanoparticles and the amine group of the alanine molecules, which may be the reason for the enhanced stability of the nanocomposite. The application of the nanocomposites as radiation detectors was evaluated by the electron spin resonance technique. The sensitivity is improved almost 3 times in the case of the nanocomposite containing 3% (w/w) gold, so it can be easily tuned by changing the amount of gold nanoparticles in the nanocomposites, without the size of the nanoparticles influencing the radiation absorption. In conclusion, the featured properties, such as homogeneity, nanoparticle size stability, and enhanced sensitivity, make these nanocomposites potential candidates for the construction of small-sized radiation sensors with tunable sensitivity for application in several medical procedures.
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Affiliation(s)
- Eder José Guidelli
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14040-901 Ribeirão Preto, São Paulo, Brazil.
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