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Pondard S, Desport C, Munier M, Kien N, Rousseau H, Merignac O, Popotte C, Moreno R. Multicentric characterization of organ-based tube current modulation in head computed tomography: A dosimetric and image quality study. Phys Med 2024; 122:103389. [PMID: 38820806 DOI: 10.1016/j.ejmp.2024.103389] [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: 10/13/2023] [Revised: 04/29/2024] [Accepted: 05/22/2024] [Indexed: 06/02/2024] Open
Abstract
PURPOSE To evaluate the efficiency of organ-based tube current modulation (OBTCM) in head Computed Tomography (CT) for different radiology departments and manufacturers. MATERIALS AND METHODS Five CT scanners from four radiology departments were evaluated in this study. All scans were performed using a standard and a routine head protocol. A scintillating fiber optic detector was placed directly on the gantry to measure the tube exit kerma. Image quality was quantified on a 16-cm HEAD phantom by measuring the signal-to-noise ratio (SNR) and the standard deviation of the Hounsfield units (HU) of circular regions of interest placed in the phantom. The Noise Power Spectrum (NPS) was also studied. Measured values were compared on images with and without OBTCM. RESULTS The reduction rates in tube exit kerma, on the anterior part, vary between 11 % and 74 % depending on the CT scanner and the protocol used. The tube exit kerma on the posterior part remains unchanged in GE and Canon CT scanners. On the contrary, the tube exit kerma to the posterior part increases by up to 39 % in Siemens CT scanner. Image noise and SNR increase by up to 10 % in the five CT scanners. Nonetheless, the differences in noise and SNR are statistically significant (p-value < 0.05).The analysis of the NPS indicates that the noise texture remains unchanged. CONCLUSION OBTCM reduces the tube exit kerma to the anterior part of the gantry without reducing substantially image quality for head protocols.
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Affiliation(s)
- Séléna Pondard
- Alara Expertise, 7 Allée de l'Europe, 67960 Entzheim, France.
| | | | - Mélodie Munier
- Fibermetrix, 7 Allée de l'Europe, 67960 Entzheim, France; Alara Group, 7 Allée de l'Europe, 67960 Entzheim, France
| | - Nicolas Kien
- Alara Expertise, 7 Allée de l'Europe, 67960 Entzheim, France
| | - Hervé Rousseau
- Service de Radiologie, CHU Toulouse Rangueil, 1 Avenue du Professeur Jean Poulhes, 31400 Toulouse, France; Institut des maladies métaboliques et cardiovasculaires (I2MC) - UMR1297, Université de Toulouse, 1 Avenue Jean Poulhès, BP64225, 31432 Toulouse, France
| | - Olivier Merignac
- Service de Radiologie Diagnostique et Interventionnelle adulte, Hôpital de Bicetre, DMU 14 Smart Imaging, AP-HP, 78 Rue du Général Leclerc 94270, Le Kremlin‑Bicetre, France; Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, 4 place du Général Leclerc, 91401 Orsay, France
| | | | - Ramiro Moreno
- Alara Expertise, 7 Allée de l'Europe, 67960 Entzheim, France; Service de Radiologie, CHU Toulouse Rangueil, 1 Avenue du Professeur Jean Poulhes, 31400 Toulouse, France; Institut des maladies métaboliques et cardiovasculaires (I2MC) - UMR1297, Université de Toulouse, 1 Avenue Jean Poulhès, BP64225, 31432 Toulouse, France.
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Jelinek M, Cip O, Lazar J, Mikel B. Design and Characterisation of an Optical Fibre Dosimeter Based on Silica Optical Fibre and Scintillation Crystal. SENSORS (BASEL, SWITZERLAND) 2022; 22:7312. [PMID: 36236411 PMCID: PMC9572585 DOI: 10.3390/s22197312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
In nuclear power plants, particle accelerators, and other nuclear facilities, measuring the level of ionising gamma radiation is critical for the safety and management of the operation and the environment's protection. However, in many cases, it is impossible to monitor ionising radiation directly at the required location continuously. This is typically either due to the lack of space to accommodate the entire dosimeter or in environments with high ionising radiation activity, electromagnetic radiation, and temperature, which significantly shorten electronics' lifetime. To allow for radiation measurement in such scenarios, we designed a fibre optic dosimeter that introduces an optical fibre link to deliver the scintillation radiation between the ionising radiation sensor and the detectors. The sensors can thus be placed in space-constrained and electronically hostile locations. We used silica optical fibres that withstand high radiation doses, high temperatures, and electromagnetic interference. We use a single photon counter and a photomultiplier to detect the transmitted scintillation radiation. We have shown that selected optical fibres, combined with different scintillation materials, are suitable for measuring gamma radiation levels in hundreds of kBq. We present the architecture of the dosimeter and its experimental characterisation with several combinations of optical fibres, detectors, and scintillation crystals.
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Affiliation(s)
- Michal Jelinek
- The Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 3058/10, 616 00 Brno, Czech Republic
- Institute of Scientific Instruments of the CAS v. v. i., 612 64 Brno, Czech Republic
| | - Ondrej Cip
- Institute of Scientific Instruments of the CAS v. v. i., 612 64 Brno, Czech Republic
| | - Josef Lazar
- Institute of Scientific Instruments of the CAS v. v. i., 612 64 Brno, Czech Republic
| | - Bretislav Mikel
- Institute of Scientific Instruments of the CAS v. v. i., 612 64 Brno, Czech Republic
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Devic C, Plagnard J, Munier M. Characterization of an Innovative Detector Based on Scintillating Fiber for Personalized Computed Tomography Dosimetry. SENSORS (BASEL, SWITZERLAND) 2021; 22:90. [PMID: 35009632 PMCID: PMC8747339 DOI: 10.3390/s22010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
For technical and radioprotection reasons, it has become essential to develop new dosimetric tools adapted to the specificities of computed tomography (CT) to ensure precise and efficient dosimetry since the current standards are not suitable for clinical use and for new CT technological evolution. Thanks to its many advantages, plastic scintillating fibers (PSF) is a good candidate for more accurate and personalized real-time dosimetry in computed tomography, and the company Fibermetrix has developed a new device named IVISCAN® based on this technology. In this study, we evaluated performances of IVISCAN® and associated uncertainties in terms of dose-rate dependence, angular dependence, stability with cumulative dose, repeatability, energy dependence, length dependence, and special uniformity in reference and clinical computed tomography beam qualities. For repeatability, the standard deviation is less than 0.039%, and the absolute uncertainty of repeatability lies between 0.017% and 0.025%. The deviation between IVISCAN® and the reference regarding energy dependence is less than 1.88% in clinical use. Dose rate dependence results show a maximum deviation under ±2%. Angular dependence standard deviation σ is 0.8%, and the absolute uncertainty was 1.6%. We observed 1% of variation every 50 Gy steps up to a cumulative dose of 500 Gy. Probe response was found to be independent of the PSF length with a maximum deviation ΔDsize < 2.7% between the IVISCAN® probe and the 1 cm PSF probe. The presented results demonstrated that IVISCAN® performances are in accordance with metrology references and the international standard IEC61674 relative to dosemeters used in X-ray diagnostic imaging and then make it an ideal candidate for real-time dosimetry in CT applications.
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Affiliation(s)
| | - Johann Plagnard
- CEA, List, Laboratoire National Henri Becquerel (LNE-LNHB), Université Paris-Saclay, 91120 Palaiseau, France;
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Inaba Y, Nakamura M, Zuguchi M, Chida K. Development of Novel Real-Time Radiation Systems Using 4-Channel Sensors. SENSORS (BASEL, SWITZERLAND) 2020; 20:E2741. [PMID: 32403386 PMCID: PMC7248883 DOI: 10.3390/s20092741] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/05/2020] [Accepted: 05/09/2020] [Indexed: 11/17/2022]
Abstract
Radiation-related tissue injuries after medical radiation procedures, such as fluoroscopically guided intervention (FGI), have been reported in patients. Real-time monitoring of medical radiation exposure administered to patients during FGI is important to avoid such tissue injuries. In our previous study, we reported a novel (prototype) real-time radiation system for FGI. However, the prototype sensor indicated low sensitivity to radiation exposure from the side and back, although it had high-quality fundamental characteristics. Therefore, we developed a novel 4-channel sensor with modified shape and size than the previous sensor, and evaluated the basic performance (i.e., measured the energy, dose linearity, dose rate, and angular dependence) of the novel and previous sensors. Both sensors of our real-time dosimeter system demonstrated the low energy dependence, excellent dose linearity (R2 = 1.0000), and good dose rate dependence (i.e., within 5% statistical difference). Besides, the sensitivity of 0° ± 180° in the horizontal and vertical directions was almost 100% sensitivity for the new sensor, which significantly improved the angular dependence. Moreover, the novel dosimeter exerted less influence on X-ray images (fluoroscopy) than other sensors because of modifying a small shape and size. Therefore, the developed dosimeter system is expected to be useful for measuring the exposure of patients to radiation doses during FGI procedures.
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Affiliation(s)
- Yohei Inaba
- Course of Radiological Technology, Health Sciences, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai, Miyagi 980-8575, Japan; (M.N.); (M.Z.); (K.C.)
- Department of Radiation Disaster Medicine, International Research Institute of Disaster Science, Tohoku University, 468-1 Aramaki Aza-Aoba, Aoba, Sendai, Miyagi 980-0845, Japan
| | - Masaaki Nakamura
- Course of Radiological Technology, Health Sciences, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai, Miyagi 980-8575, Japan; (M.N.); (M.Z.); (K.C.)
| | - Masayuki Zuguchi
- Course of Radiological Technology, Health Sciences, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai, Miyagi 980-8575, Japan; (M.N.); (M.Z.); (K.C.)
| | - Koichi Chida
- Course of Radiological Technology, Health Sciences, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai, Miyagi 980-8575, Japan; (M.N.); (M.Z.); (K.C.)
- Department of Radiation Disaster Medicine, International Research Institute of Disaster Science, Tohoku University, 468-1 Aramaki Aza-Aoba, Aoba, Sendai, Miyagi 980-0845, Japan
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Wong JHD, Bakhsh M, Cheah YY, Jong WL, Khor JS, Ng KH. CHARACTERISATION AND EVALUATION OF AL2O3:C-BASED OPTICALLY STIMULATED LUMINESCENT DOSEMETER SYSTEM FOR DIAGNOSTIC X-RAYS: PERSONAL AND IN VIVO DOSIMETRY. RADIATION PROTECTION DOSIMETRY 2019; 187:451-460. [PMID: 31650160 DOI: 10.1093/rpd/ncz186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
This study characterises and evaluates an Al2O3:C-based optically stimulated luminescent dosemeter (OSLD) system, commercially known as the nanoDot™ dosemeter and the InLight® microStar reader, for personal and in vivo dose measurements in diagnostic radiology. The system characteristics, such as dose linearity, reader accuracy, reproducibility, batch homogeneity, energy dependence and signal stability, were explored. The suitability of the nanoDot™ dosemeters was evaluated by measuring the depth dose curve, in vivo dose measurement and image perturbation. The nanoDot™ dosemeters were observed to produce a linear dose with ±2.8% coefficient variation. Significant batch inhomogeneity (8.3%) was observed. A slight energy dependence (±6.1%) was observed between 60 and 140 kVp. The InLight® microStar reader demonstrated good accuracy and a reproducibility of ±2%. The depth dose curve measured using nanoDot™ dosemeters showed slightly lower responses than Monte Carlo simulation results. The total uncertainty for a single dose measurement using this system was 11%, but it could be reduced to 9.2% when energy dependence correction was applied.
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Affiliation(s)
- J H D Wong
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
- University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - M Bakhsh
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Y Y Cheah
- Department of Biomedical Imaging, 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
| | - J S Khor
- Department of Biomedical Imaging, 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
- University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
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Johnstone CD, Therriault-Proulx F, Beaulieu L, Bazalova-Carter M. Characterization of a plastic scintillating detector for the Small Animal Radiation Research Platform (SARRP). Med Phys 2018; 46:394-404. [PMID: 30417377 DOI: 10.1002/mp.13283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 10/07/2018] [Accepted: 10/30/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The purpose of this study was to characterize a small plastic scintillator developed for high resolution, real-time dosimetry of therapy and imaging x-ray beams delivered by an image-guided small animal irradiator. MATERIALS AND METHODS A 1 mm diameter, 1 mm long polystyrene BCF-60 scintillating fiber dosimeter was characterized with 220 kVp therapy and 40, 50, 60, 70, and 80 kVp imaging beams on the Small Animal Research Platform (SARRP). Scintillator output, sensitivity (charge per unit dose), linearity, and 0.2-mm resolution beam profile measurements were performed. A validated in-house Monte Carlo (MC) model of the SARRP was used to compute detailed energy spectra at locations of dosimetry, and validated scintillator measurement with MC simulations. Mass energy-absorption coefficients from the National Institute of Standards and Technology (NIST) tables convolved with MC-derived spectra were used in conjunction with Birks ionization quenching factors to correct scintillator output. An air kerma calibration method was employed to correct scintillator output for in-air beam profile measurements with open, 5 × 5, and 3 × 3 mm2 square field sizes, and compared to MC simulations. RESULTS Scintillator dose response showed excellent linearity (R2 ≥ 0.999) for all sensitivity measurements, including output as a function of tube current. Detector sensitivity was 2.41 μC Gy-1 for the 220 kVp therapy beam, and it ranged from 1.21 to 1.32 μC Gy-1 for the 40-80 imaging beams. Percentage difference in sensitivity between the therapy and imaging beams before sensitivity correction and after using the Birks quenching factors were 52.3% and 10.2%, respectively. Percentage differences between the therapy and imaging beam sensitivities after using the air kerma calibration method for in-air measurements was excellent and below 0.3%. In-air beam profile measurements agreed to MC simulations within a mean difference of 2.4% for the 5 × 5 and 3 × 3 mm2 field sizes, however, the scintillator showed signs of volume averaging at the penumbra edges. CONCLUSIONS A small plastic scintillator was characterized for therapy and imaging energies of a small animal irradiator, with output corrected for using an in-house MC model of the irradiator. The characterization of the scintillator detector system for small fields presents steps toward implementing real-time measurements for quality assurance and small animal treatment and imaging dose verification.
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Affiliation(s)
| | - François Therriault-Proulx
- Departement de Radio-Oncologie and Centre de recherche du CHU de Quebec, CHU de Quebec, Quebec, QC, G1R 3S1, Canada
| | - Luc Beaulieu
- Departement de Radio-Oncologie and Centre de recherche du CHU de Quebec, CHU de Quebec, Quebec, QC, G1R 3S1, Canada.,Departement de physique and Centre de recherche sur le Cancer, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Magdalena Bazalova-Carter
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada
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Beaulieu L, Beddar S. Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy. Phys Med Biol 2016; 61:R305-R343. [DOI: 10.1088/0031-9155/61/20/r305] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Boivin J, Beddar S, Bonde C, Schmidt D, Culberson W, Guillemette M, Beaulieu L. A systematic characterization of the low-energy photon response of plastic scintillation detectors. Phys Med Biol 2016; 61:5569-86. [DOI: 10.1088/0031-9155/61/15/5569] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Performance Evaluation of a Multichannel All-In-One Phantom Dosimeter for Dose Measurement of Diagnostic X-ray Beam. SENSORS 2015; 15:28490-501. [PMID: 26569252 PMCID: PMC4701291 DOI: 10.3390/s151128490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/26/2015] [Accepted: 11/05/2015] [Indexed: 12/14/2022]
Abstract
We developed a multichannel all-in-one phantom dosimeter system composed of nine sensing probes, a chest phantom, an image intensifier, and a complementary metal-oxide semiconductor (CMOS) image sensor to measure the dose distribution of an X-ray beam used in radiation diagnosis. Nine sensing probes of the phantom dosimeter were fabricated identically by connecting a plastic scintillating fiber (PSF) to a plastic optical fiber (POF). To measure the planar dose distribution on a chest phantom according to exposure parameters used in clinical practice, we divided the top of the chest phantom into nine equal parts virtually and then installed the nine sensing probes at each center of the nine equal parts on the top of the chest phantom as measuring points. Each scintillation signal generated in the nine sensing probes was transmitted through the POFs and then intensified by the image intensifier because the scintillation signal normally has a very low light intensity. Real-time scintillation images (RSIs) containing the intensified scintillation signals were taken by the CMOS image sensor with a single lens optical system and displayed through a software program. Under variation of the exposure parameters, we measured RSIs containing dose information using the multichannel all-in-one phantom dosimeter and compared the results with the absorbed doses obtained by using a semiconductor dosimeter (SCD). From the experimental results of this study, the light intensities of nine regions of interest (ROI) in the RSI measured by the phantom dosimeter were similar to the dose distribution obtained using the SCD. In conclusion, we demonstrated that the planar dose distribution including the entrance surface dose (ESD) can be easily measured by using the proposed phantom dosimeter system.
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Effects of Temperature and X-rays on Plastic Scintillating Fiber and Infrared Optical Fiber. SENSORS 2015; 15:11012-26. [PMID: 25970257 PMCID: PMC4481907 DOI: 10.3390/s150511012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 11/24/2022]
Abstract
In this study, we have studied the effects of temperature and X-ray energy variations on the light output signals from two different fiber-optic sensors, a fiber-optic dosimeter (FOD) based on a BCF-12 as a plastic scintillating fiber (PSF) and a fiber-optic thermometer (FOT) using a silver halide optical fiber as an infrared optical fiber (IR fiber). During X-ray beam irradiation, the scintillating light and IR signals were measured simultaneously using a dosimeter probe of the FOD and a thermometer probe of the FOT. The probes were placed in a beaker with water on the center of a hotplate, under variation of the tube potential of a digital radiography system or the temperature of the water in the beaker. From the experimental results, in the case of the PSF, the scintillator light output at the given tube potential decreased as the temperature increased in the temperature range from 25 to 60 °C. We demonstrated that commonly used BCF-12 has a significant temperature dependence of −0.263 ± 0.028%/°C in the clinical temperature range. Next, in the case of the IR fiber, the intensity of the IR signal was almost uniform at each temperature regardless of the tube potential range from 50 to 150 kVp. Therefore, we also demonstrated that the X-ray beam with an energy range used in diagnostic radiology does not affect the IR signals transmitted via a silver halide optical fiber.
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