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Timeline of Sang Hun Shin

2018
Apr
24
Published new article






Real-time detection of 192Ir gamma-ray source positon using organic scintillator array sensor in HDR brachytherapy

Published: 24 April 2018 by SPIE-Intl Soc Optical Eng in Biomedical Imaging and Sensing Conference

doi: 10.1117/12.2319367

In this study, we fabricated an organic scintillator array sensor (OSAS) based the array of organic scintillators. The scintillator array of OSAS for detecting positions of 192Ir gamma-ray source was fabricated using four types of organic scintillators, which emit the scintillating lights of different wavelength, respectively. To evaluate the performance of the OSAS, 192Ir gamma-ray source employed in a HDR brachytherapy was used. In this research, the spectra were measured with positions of 192Ir gamma-ray source which was moved at intervals of 5 mm and 10 mm using the OSAS. The experimental results show that the proposed OSAS can measure and discriminate the wavelength of scintillating lights generated in the OSAS according to the positions of 192Ir gamma-ray source. It is expected that the OSAS can used to detect positions of 192Ir gamma-ray source during a HDR brachytherapy. Further studies are planned to fabricate the OSAS with the different intervals of movements and the small size of organic scintillators.

0 Reads | 0 Citations
2017
Nov
19
Published new article




Article

Characterization of light transmissions in various optical fibers with proton beam

Published: 19 November 2017 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.71.842

4 Reads | 0 Citations
2017
Jul
25
Published new article




Article

Simultaneous measurement of alpha and beta particles using dual-type fiber-optic radiation sensor

Published: 25 July 2017 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.71.923

In this study, we fabricated a dual-type fiber-optic radiation sensor (DFORS) system using a spectroscopic technique, for simultaneous and separate measurement of alpha and beta particles. The DFORS is composed of a sensing probe, plastic optical fiber (POF), photomultiplier tube (PMT)- amplifier system, and multichannel analyzer (MCA). A dual scintillator consisting of a ZnS(Ag) film and a CaF2(Eu) crystal was used for alpha and beta spectroscopy as a sensing probe. 210Po and 90Sr were used as alpha and beta emitters, respectively, and alpha and beta energy spectra were measured using the proposed DFORS system to discriminate species of the radioisotopes emitting alpha or beta particles. From the experimental results, we demonstrated that the small-sized, flexible, and insertable DFORS system could discriminate the alpha and beta events successfully using the spectral information of each radiation sources.

0 Reads | 0 Citations
2017
Apr
18
Published new article






Dual type fiber-optic radiation sensor for measuring alpha and beta particles

Published: 18 April 2017 by SPIE-Intl Soc Optical Eng in Biomedical Imaging and Sensing Conference

doi: 10.1117/12.2274723

In this study, we fabricated a dual type fiber-optic radiation sensor (DFORS) system using a spectroscopic technique to measure alpha and beta particles simultaneously and separately. The DFORS is composed of a sensing probe, a plastic optical fiber (POF), a photomultiplier tube (PMT)-amplifier system, and a multichannel analyzer (MCA). As sensing probes, a ZnS(Ag) film and CaF2(Eu) crystal were used for alpha and beta spectroscopy. And, we measured the alpha and beta energy spectra using the proposed DFORS system to discriminate species of the radioisotopes emitting alpha or beta particle. From the experimental results, we demonstrated that the small-sized, flexible, and insertable DFORS system can measure and discriminate the alpha and beta successfully with the spectral information of each radioisotope. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

3 Reads | 0 Citations
2016
Sep
30
Published new article




Article

Silicon Oil-Based 2-Channel Fiber-Optic Temperature Sensor Using a Subtraction Method

Published: 30 September 2016 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/JSST.2016.25.5.344

3 Reads | 0 Citations
2016
Jul
05
Published new article




Article

Measurement of therapeutic photon beams-induced Cerenkov radiation generated in PMMA- and PS-based plastic optical fiber...

Published: 05 July 2016 by Springer Nature in Optical Review

doi: 10.1007/s10043-016-0240-8

In this study, we characterized Cerenkov radiation generated in polystyrene (PS)- and polymethyl methacrylate (PMMA)-based plastic optical fibers (POFs) to select an adequate optical fiber for producing Cerenkov radiation. To determine the relationship between the absorbed dose and the intensity of Cerenkov radiation, we calculated the energy depositions of photon beams and fluxes of electrons inducing Cerenkov radiation using the Monte Carlo N-Particle eXtended code. Also, intensities of Cerenkov radiation generated in PS- and PMMA-based POFs were measured as functions of dose rate and monitor unit. At last, therapeutic photon beams-induced Cerenkov radiation in PS- and PMMA-based POFs was measured according to depths of solid water phantom.

0 Reads | 0 Citations
2015
Nov
17
Published new article




Article

Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry

Published: 17 November 2015 by MDPI in Sensors

doi: 10.3390/s151129003

In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter.

0 Reads | 0 Citations
2015
Nov
11
Published new article




Article

Performance Evaluation of a Multichannel All-In-One Phantom Dosimeter for Dose Measurement of Diagnostic X-ray Beam

Published: 11 November 2015 by MDPI in Sensors

doi: 10.3390/s151128490

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.

0 Reads | 0 Citations
2015
Nov
01
Published new article




Article

Fiber-optic Temperature Sensor Using a Silicone Oil and an OTDR

Published: 01 November 2015 by Informa UK Limited in The Transactions of The Korean Institute of Electrical Engineers

doi: 10.5370/kiee.2015.64.11.1592

5 Reads | 0 Citations
2015
Jul
28
Published new article




Article

Feasibility study on the development of a fiber-optic gamma imaging probe

Published: 28 July 2015 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.67.175

In this research, we fabricated a fiber-optic gamma imaging probe that could measure the scintillation image induced by gamma-rays. For evaluating the spatial resolution of the optical and the scintillation images measured by using the proposed gamma imaging probe, first, we obtained the light intensity distributions across the sharp edge from the optical and the scintillation images by using a USAF 1951 resolution target and an X-ray beam and then analyzed each modulation transfer function (MTF) curve. Next, we measured the scintillation images with information regarding the distribution by the gamma-rays emitted from Cs-137 sources with four different radioactivities. Finally, we evaluated the intensity variation of the scintillating light from the region of interest (ROI) in the scintillation image according to the radioactivity of Cs-137.

2 Reads | 0 Citations
2015
May
31
Published new article




Article

Fabrication and Performance Evaluation of a Scintillating Film-based Gamma Imaging Detector to Measure Gamma-ray Distrib...

Published: 31 May 2015 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2015.24.3.202

1 Reads | 0 Citations
2015
Jan
20
Published new article




Article

Thermal properties of a fiber-optic radiation sensor for measuring gamma-rays in high-temperature conditions

Published: 20 January 2015 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.66.46

A fiber-optic radiation sensor (FORS) was fabricated using a cerium-doped silicate-yttriumlutetium (LYSO:Ce) scintillator crystal and a silica optical fiber (SOF) to measure gamma-rays accurately in elevated temperature conditions. Throughout this study, a LYSO:Ce crystal was employed as a sensing material of the FORS due to its high light yield (32,000 photons/MeV), fast decay time (≤ 47 ns) and high detection efficiency. Although the LYSO:Ce crystal has many desirable qualities, the thermoluminescence (TL) should be eliminated by using a heat annealing process because the light yield of the LYSO:Ce crystal varies with its TL. In this study, therefore, we obtained the TL curve of the LYSO:Ce crystal by increasing the temperature up to 280 ℃, and we demonstrated that almost all of the TL of the LYSO:Ce crystal was eliminated by the heat annealing process.

0 Reads | 0 Citations
2015
Jan
20
Published new article




Article

Fundamental research on a cerenkov radiation sensor based on optical glass for detecting beta-rays

Published: 20 January 2015 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.66.51

In this study, a Cerenkov radiation sensor for detecting low-energy beta-particles was fabricated using various Cerenkov radiators such as an aerogel and CaF2-, SiO2-, and Al2O3-based optical glasses. Because the Cerenkov threshold energy (CTE) is determined by the refractive index of the Cerenkov radiator, the intensity of Cerenkov radiation varies according to the refractive indices of the Cerenkov radiators. Therefore, we measured the intensities of Cerenkov radiation induced by beta-particles generated from a radioactive isotope as a function of the refractive indices of the Cerenkov radiators. Also, the electron fluxes were calculated for various Cerenkov radiators by using a Monte Carlo N-Particle extended transport code (MCNPX) to determine the relationship between the intensities of the Cerenkov radiation and the electron fluxes.

0 Reads | 0 Citations
2015
Jan
01
Published new article




Article

Comparison of Optical and Scintillation Images Obtained by Using a Fiber-Optic Beta/Gamma Imaging Detector

Published: 01 January 2015 by Trans Tech Publications in Advanced Materials Research

doi: 10.4028/www.scientific.net/amr.1083.137

We developed a fiber-optic beta/gamma imaging detector that can obtain the scintillating images for beta-or gamma-ray emitted from the radioisotope. To evaluate spatial resolution of proposed imaging detector, we obtained the optical images using USAF 1951 resolution target. And then, a modulation transfer function curve of the optical image was calculated. Also, we measured the scintillating images of Tl-204 and Cs-137 with information respecting the beta-and gamma-rays distribution. Finally, the intensities of scintillating light as a function of radioactivity were analyzed from the region of interest in the scintillating image.

0 Reads | 0 Citations
2014
Oct
10
Published new article




Article

A Fiber-Optic Sensor Using an Aqueous Solution of Sodium Chloride to Measure Temperature and Water Level Simultaneously

Published: 10 October 2014 by MDPI in Sensors

doi: 10.3390/s141018823

A fiber-optic sensor system using a multiplexed array of sensing probes based on an aqueous solution of sodium chloride (NaCl solution) and an optical time-domain reflectometer (OTDR) for simultaneous measurement of temperature and water level is proposed. By changing the temperature, the refractive index of the NaCl solution is varied and Fresnel reflection arising at the interface between the distal end of optical fiber and the NaCl solution is then also changed. We measured the modified optical power of the light reflected from the sensing probe using a portable OTDR device and also obtained the relationship between the temperature of water and the optical power. In this study, the water level was simply determined by measuring the signal difference of the optical power due to the temperature difference of individual sensing probes placed inside and outside of the water. In conclusion, we demonstrate that the temperature and water level can be obtained simultaneously by measuring optical powers of light reflected from sensing probes based on the NaCl solution. It is anticipated that the proposed fiber-optic sensor system makes it possible to remotely monitor the real-time change of temperature and water level of the spent fuel pool during a loss of power accident.

4 Reads | 1 Citations
2014
Oct
01
Published new article




Article

Measurement of Therapeutic Proton Beam Using a Fiber-Optic Cerenkov Radiation Sensor

Published: 01 October 2014 by Trans Tech Publications in Advanced Materials Research

doi: 10.4028/www.scientific.net/amr.1033-1034.431

Tumor therapy using the high-energy radiation has evolved over the decades as typical non-invasive treatment method due to its advantage compared with surgery. But, the radiotherapy can damage or destroy normal cells as well as destroying tumor cells and cause side effects of treatment. Even though most side effects are temporary, these effects can be extremely fatal for patient. Therefore, the exact measurement of the exposure dose of patient during radiation therapy is very important for patient safety. In the case of the conventional fiber-optic radiation sensor that consists of a scintillator for high-energy radiation dosimetry, additional correction is necessary due to the quenching effects of the scintillator. In this study, we measured the exposure dose of the high-energy proton beam without the scintillator by using the Cerenkov radiation that generated inside the plastic optical fiber. As a result of this study, we confirmed a Bragg peak of the proton beam without a scintillator. Also it was in good agreement with the result of the ionization chamber.

0 Reads | 0 Citations
2014
Oct
01
Published new article




Article

Estimation of Cerenkov Radiation Generated in Various Dielectrics Using MCNPX Simulation

Published: 01 October 2014 by Trans Tech Publications in Advanced Materials Research

doi: 10.4028/www.scientific.net/amr.1033-1034.1127

To estimate Cerenkov radiation generated in various dielectric materials, in this study, we calculated therapeutic photon beams induced electron fluxes in a CaF2, PMMA, SiO2 and Al2O3 by using the Monte Carlo N-particle Extended transport code (MCNPX). Also, we clarified the relationship between electron fluxes produced in various dielectrics and energy depositions in water by irradiation of therapeutic photon beams. The electron fluxes and the energy depositions were calculated as a function of water depth.

0 Reads | 0 Citations
2014
Sep
01
Published new article




Article

Feasibility study on fiber-optic goniometer for measuring knee joint angle

Published: 01 September 2014 by Springer Nature in Optical Review

doi: 10.1007/s10043-014-0112-z

In this study, we fabricated a fiber-optic goniometer using a plastic optical fiber, a light-emitting diode, and a photodiode. The cladding of the plastic optical fiber was removed at 0.5–3mm intervals regularly to increase the bending loss of the plastic optical fiber. Also, the output voltages of the photodiode based on light intensity that measured using the fiber-optic goniometer were measured light intensities using the fiber-optic goniometer were measured to evaluate the linearity of the fiber-optic goniometer. Finally, we measured the responses of the fiber-optic goniometer for gait speeds of 3, 5, and 10 km/h using a data acquisition board and a LabVIEW program.

0 Reads | 1 Citations
2014
Jul
31
Published new article




Article

Performance Evaluation of a Fiber-Optic Cerenkov Radiation Sensor System Using a Simulated Spent Fuel Assembly

Published: 31 July 2014 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2014.23.4.245

0 Reads | 0 Citations
2014
Apr
21
Published new article




Article

Measurement of Cerenkov Radiation Induced by the Gamma-Rays of Co-60 Therapy Units Using Wavelength Shifting Fiber

Published: 21 April 2014 by MDPI in Sensors

doi: 10.3390/s140407013

In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%.

5 Reads | 4 Citations
2014
Apr
01
Published new article




Article

Measurement of Entrance Surface Dose on an Anthropomorphic Thorax Phantom Using a Miniature Fiber-Optic Dosimeter

Published: 01 April 2014 by MDPI in Sensors

doi: 10.3390/s140406305

A miniature fiber-optic dosimeter (FOD) system was fabricated using a plastic scintillating fiber, a plastic optical fiber, and a multi-pixel photon counter to measure real-time entrance surface dose (ESD) during radiation diagnosis. Under varying exposure parameters of a digital radiography (DR) system, we measured the scintillating light related to the ESD using the sensing probe of the FOD, which was placed at the center of the beam field on an anthropomorphic thorax phantom. Also, we obtained DR images using a flat panel detector of the DR system to evaluate the effects of the dosimeter on image artifacts during posteroanterior (PA) chest radiography. From the experimental results, the scintillation output signals of the FOD were similar to the ESDs including backscatter simultaneously obtained using a semiconductor dosimeter. We demonstrated that the proposed miniature FOD can be used to measure real-time ESDs with minimization of DR image artifacts in the X-ray energy range of diagnostic radiology.

5 Reads | 3 Citations
2014
Feb
01
Published new article




Article

Feasibility Study on Development of a Fiber-Optic Dual Detector to Measure Beta- and Gamma-rays Simultaneously

Published: 01 February 2014 by Informa UK Limited in The Transactions of The Korean Institute of Electrical Engineers

doi: 10.5370/kiee.2014.63.2.284

0 Reads | 1 Citations
2013
Nov
18
Published new article




Article

Simultaneous measurements of pure scintillation and Cerenkov signals in an integrated fiber-optic dosimeter for electron...

Published: 18 November 2013 in Optics Express

doi:

For real-time dosimetry in electron beam therapy, an integrated fiber-optic dosimeter (FOD) is developed using a water-equivalent dosimeter probe, four transmitting optical fibers, and a multichannel light-measuring device. The dosimeter probe is composed of two inner sensors, a scintillation sensor and a Cerenkov sensor, and each sensor has two different channels. Accordingly, we measured four separate light signals from each channel in the dosimeter probe, simultaneously, and then obtained the scintillation and Cerenkov signals using a subtraction method. To evaluate the performance of the integrated FOD, we measured the light signals according to the irradiation angle of the electron beam, the depth variation of the solid water phantom, and the electron beam energy. In conclusion, we demonstrated that the pure scintillation and Cerenkov signals obtained by an integrated FOD system based on a subtraction method can be effectively used for calibrating the conditions of high-energy electron beams in radiotherapy.

0 Reads | 0 Citations
2013
Nov
05
Published new article




Article

Simultaneous measurements of pure scintillation and Cerenkov signals in an integrated fiber-optic dosimeter for electron...

Published: 05 November 2013 by The Optical Society in Optics Express

doi: 10.1364/oe.21.027770

For real-time dosimetry in electron beam therapy, an integrated fiber-optic dosimeter (FOD) is developed using a water-equivalent dosimeter probe, four transmitting optical fibers, and a multichannel light-measuring device. The dosimeter probe is composed of two inner sensors, a scintillation sensor and a Cerenkov sensor, and each sensor has two different channels. Accordingly, we measured four separate light signals from each channel in the dosimeter probe, simultaneously, and then obtained the scintillation and Cerenkov signals using a subtraction method. To evaluate the performance of the integrated FOD, we measured the light signals according to the irradiation angle of the electron beam, the depth variation of the solid water phantom, and the electron beam energy. In conclusion, we demonstrated that the pure scintillation and Cerenkov signals obtained by an integrated FOD system based on a subtraction method can be effectively used for calibrating the conditions of high-energy electron beams in radiotherapy.

0 Reads | 8 Citations
2013
Nov
01
Published new article




Article

Development of a Cerenkov radiation sensor to detect low-energy beta-particles

Published: 01 November 2013 by Elsevier BV in Applied Radiation and Isotopes

doi: 10.1016/j.apradiso.2013.03.075

Highlights•Development of a fiber-optic Cerenkov radiation sensor to measure beta-particles.•Usage of transparent refractive index liquids having various refractive indices as Cerenkov radiators.•Measurements of the Cerenkov radiation according to the refractive index of the Cerenkov radiator. AbstractWe fabricated a novel fiber-optic Cerenkov radiation sensor using a Cerenkov radiator for measuring beta-particles. Instead of employing a scintillator, transparent liquids having various refractive indices were used as a Cerenkov radiator to serve as a sensing material. The experimental results showed that the amount of Cerenkov radiation due to the interaction with beta-particles increased as the refractive index of the Cerenkov radiator was increased as a results of a decrease of the Cerenkov threshold energy for electrons.

4 Reads | 6 Citations
2013
Jul
01
Published new article




Article

Performance Evaluation of Fiber-Optic Dosimeter According to Current-Time Product of Digital Radiography System

Published: 01 July 2013 by Trans Tech Publications in Advanced Materials Research

doi: 10.4028/www.scientific.net/amr.718-720.576

A fiber-optic dosimeter was developed using a plastic scintillating fiber, a plastic optical fiber, and a photomultiplier tube for measuring entrance surface dose over the low-energy range which is interested in diagnostic radiology. To evaluate the fabricated fiber-optic dosimeter, the scintillating light signals were measured by changing the current-time product whose values were determined by tube current and irradiation time of a digital radiography system. In conclusion, the trend of scintillating light signals of the fiber-optic dosimeter was similar with that of the entrance surface doses of a commercially available semiconductor dosimeter according to the current-time product.

0 Reads | 0 Citations
2013
Jun
17
Published new article




Article

Feasibility of fiber-optic radiation sensor using Cerenkov effect for detecting thermal neutrons.

Published: 17 June 2013 in Optics Express

doi:

In this research, we propose a novel method for detecting thermal neutrons with a fiber-optic radiation sensor using the Cerenkov effect. We fabricate a fiber-optic radiation sensor that detects thermal neutrons with a Gd-foil, a rutile crystal, and a plastic optical fiber. The relationship between the fluxes of electrons inducing Cerenkov radiation in the sensor probe of the fiber-optic radiation sensor and thermal neutron fluxes is determined using the Monte Carlo N-particle transport code simulations. To evaluate the fiber-optic radiation sensor, the Cerenkov radiation generated in the fiber-optic radiation sensor by irradiation of pure thermal neutron beams is measured according to the depths of polyethylene.

0 Reads | 0 Citations
2013
Jun
11
Published new article




Article

Feasibility of fiber-optic radiation sensor using Cerenkov effect for detecting thermal neutrons

Published: 11 June 2013 by The Optical Society in Optics Express

doi: 10.1364/oe.21.014573

In this research, we propose a novel method for detecting thermal neutrons with a fiber-optic radiation sensor using the Cerenkov effect. We fabricate a fiber-optic radiation sensor that detects thermal neutrons with a Gd-foil, a rutile crystal, and a plastic optical fiber. The relationship between the fluxes of electrons inducing Cerenkov radiation in the sensor probe of the fiber-optic radiation sensor and thermal neutron fluxes is determined using the Monte Carlo N-particle transport code simulations. To evaluate the fiber-optic radiation sensor, the Cerenkov radiation generated in the fiber-optic radiation sensor by irradiation of pure thermal neutron beams is measured according to the depths of polyethylene.

4 Reads | 6 Citations
2013
Apr
01
Published new article




Article

Measurements of Cerenkov Lights Using Optical Fibers

Published: 01 April 2013 by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Nuclear Science

doi: 10.1109/tns.2013.2252623

Optical fibers can be a medium to produce Cerenkov light due to their dielectric components, and radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, we measured and characterized gamma-ray induced Cerenkov light in silica optical fibers, a plastic optical fiber, and a plastic wavelength shifting fiber in order to select the adequate optical fiber for producing Cerenkov light. Also, we measured the intensity of Cerenkov light as functions of irradiated length, irradiation angle, and thickness of various scatterers using the chosen optical fiber.

0 Reads | 1 Citations
2013
Mar
27
Published new article




Article

Measurements of entrance surface dose using a fiber-optic dosimeter in diagnostic radiology

Published: 27 March 2013 by Springer Nature in Optical Review

doi: 10.1007/s10043-013-0028-z

In this study, a fiber-optic dosimeter (FOD) was developed to measure entrance surface dose (ESD) in diagnostic radiology. We measured the scintillating lights in order to obtain ESDs, which changed with the various exposure parameters of a digital radiography (DR) system, such as tube potential, current-time product, focus-surface distance (FSD), and field size, using the fabricated FOD system. From the experimental results, the output light signals of the FOD were similar to the ESDs of the conventional semiconductor dosimeter. In conclusion, we characterized the measured ESDs as functions of exposure parameters by using two different types of dosimeters and demonstrated that the proposed FOD using a plastic scintillating fiber and a plastic optical fiber (POF) makes it possible to measure ESDs in the energy range of diagnostic radiology. From the results of this study, it is anticipated that the FOD will be a useful dosimeter in low-energy photon applications including diagnostic radiology.

3 Reads | 1 Citations
2013
Mar
27
Published new article




Article

Measurements of planar and depth dose distributions using a scintillating fiber-optic image sensor system for dosimetry ...

Published: 27 March 2013 by Springer Nature in Optical Review

doi: 10.1007/s10043-013-0029-y

We developed a scintillating fiber-optic image sensor system (SFISS) using square plastic optical fibers (POFs), a scintillating film, a right-angle mirror, and a complementary metal-oxide semiconductor (CMOS) image camera for dosimetry in radiotherapeutic applications. In this study, the scintillating light images were obtained for measuring two-dimensional planar dose distributions of a 6MV photon beam in a solid-water phantom. We also measured the percentage depth doses (PDDs) of 6 and 15MV photon beams using the SFISS and compared them with those obtained using conventional dosimetry films. The proposed sensor has many advantages, such as real-time readout, high-resolution measurement, and lack of corrections for temperature, pressure, and humidity. From the results of this study, it is expected that a SFISS can be developed to accurately measure the dose distribution in a small beam field for stereotactic radiosurgery (SRS).

2 Reads | 1 Citations
2013
Mar
27
Published new article




Article

Optical fiber-based gamma-ray spectroscopy with cerium-doped lutetium yttrium orthosilicate crystal

Published: 27 March 2013 by Springer Nature in Optical Review

doi: 10.1007/s10043-013-0036-z

A fiber-optic radiation sensor (FORS), which is composed of an inorganic scintillator, a plastic optical fiber (POF), a photomultiplier tube (PMT), and a multichannel analyzer (MCA), was developed for gamma-ray energy spectroscopy. In this study, we selected a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) as the sensitive element of the FORS and found that LYSO:Ce with dimensions of 3 × 3 × 15mm3 gives the best performance in obtaining a gammaray energy spectrum. The FORS allows us to measure the energy spectra of Co-60, Na-22, and Cs-137.

4 Reads | 2 Citations
2013
Mar
27
Published new article




Article

Fiber-optic pH sensor based on sol-gel film immobilized with neutral red

Published: 27 March 2013 by Springer Nature in Optical Review

doi: 10.1007/s10043-013-0037-y

In this study, we developed a fiber-optic pH sensor based on a sol-gel film immobilized with neutral red (NR). A solgel film was prepared by mixing tetramethylorthosilicate (TMOS), trimethoxymethylsilane (MTMS), ethanol (EtOH), distilled water (H2O), and NR powder. Accordingly, the thin pH sol-gel film was fabricated through a sol-gel process with a dip-coating method. The thickness and diameter of the fabricated pH sol-gel film are 0.11 and 0.6 mm, respectively. We measured the optical absorbance and the light intensity with the spectra of reflected light, which change with the color variation of the pH sol-gel film in the fiber-optic sensing probe. From the experimental results, we demonstrated that the proposed fiber-optic pH sensor has good reversibility, reproducibility, and a fast response time, in which the optical properties of the NR-based pH sol-gel film change with the pH value.

6 Reads | 14 Citations
2013
Feb
01
Published new article




Article

Application of Cerenkov radiation generated in plastic optical fibers for therapeutic photon beam dosimetry

Published: 01 February 2013 by SPIE-Intl Soc Optical Eng in Journal of Biomedical Optics

doi: 10.1117/1.jbo.18.2.027001

A Cerenkov fiber-optic dosimeter (CFOD) is fabricated using plastic optical fibers to measure Cerenkov radiation induced by a therapeutic photon beam. We measured the Cerenkov radiation generated in optical fibers in various irradiation conditions to evaluate the usability of Cerenkov radiation for a photon beam therapy dosimetry. As a results, the spectral peak of Cerenkov radiation was measured at a wavelength of 515 nm, and the intensity of Cerenkov radiation increased linearly with increasing irradiated length of the optical fiber. Also, the intensity peak of Cerenkov radiation was measured in the irradiation angle range of 30 to 40 deg. In the results of Monte Carlo N-particle transport code simulations, the relationship between fluxes of electrons over Cerenkov threshold energy and energy deposition of a 6 MV photon beam had a nearly linear trend. Finally, percentage depth doses for the 6 MV photon beam could be obtained using the CFOD and the results were compared with those of an ionization chamber. Here, the mean dose difference was about 0.6%. It is anticipated that the novel and simple CFOD can be effectively used for measuring depth doses in radiotherapy dosimetry.

0 Reads | 15 Citations
2013
Jan
04
Published new article






Performance Evaluation of Fiber-Optic Radiation Sensor Using Spectroscopic Technique for Measurement of Alpha and Beta P...

Published: 04 January 2013 by Global Science & Technology Forum Pte Ltd. in Annual International Conference on Optoelectronics, Photonics & Applied Physics

doi: 10.5176/2301-3516_opap13.29

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2013
Jan
01
Published new article




Article

Development of a scintillating fiber-optic dosimeter for measuring the entrance surface dose in diagnostic radiology

Published: 01 January 2013 by Elsevier BV in Radiation Measurements

doi: 10.1016/j.radmeas.2012.11.001

0 Reads | 3 Citations
2012
Nov
01
Published new article




Article

Development of a fiber-optic Cerenkov radiation sensor to verify spent fuel: Characterization of the Cerenkov radiation ...

Published: 01 November 2012 by Korean Physical Society in Journal of the Korean Physical Society

doi: 10.3938/jkps.61.1704

In this study, we characterized the Cerenkov radiation generated from optical fibers as fundamental research for the development of a fiber-optic Cerenkov radiation sensor to verify spent fuel. We measured the amount of Cerenkov radiation according to OH content and numerical aperture of the optical fiber. Also, we measured the Cerenkov radiation as functions of the length and the diameter of the optical fiber. As a result, the silica optical fibers with high numerical aperture and high OH content were efficient and stable for gathering the Cerenkov radiation generated in the optical fiber. Also, the intensity of the Cerenkov radiation generated in the optical fiber was proportional to the irradiated length and to the square of the irradiated diameter.

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2012
Sep
30
Published new article




Article

Fabrication and Characterization of a Fiber-Optic Alpha/Beta Detector for Nuclear Medicine Application

Published: 30 September 2012 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2012.21.5.367

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2012
Jul
31
Published new article




Article

Development of Fiber-optic Radiation Sensor Using LYSO Scintillator for Gamma-ray Spectroscopy

Published: 31 July 2012 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2012.21.4.287

0 Reads | 1 Citations
2012
Jun
18
Published new article




Article

Fiber-optic Cerenkov radiation sensor for proton therapy dosimetry.

Published: 18 June 2012 in Optics Express

doi:

In proton therapy dosimetry, a fiber-optic radiation sensor incorporating a scintillator must undergo complicated correction processes due to the quenching effect of the scintillator. To overcome the drawbacks of the fiber-optic radiation sensor, we proposed an innovative method using the Cerenkov radiation generated in plastic optical fibers. In this study, we fabricated a fiber-optic Cerenkov radiation sensor without an organic scintillator to measure Cerenkov radiation induced by therapeutic proton beams. Bragg peaks and spread-out Bragg peaks of proton beams were measured using the fiber-optic Cerenkov radiation sensor and the results were compared with those of an ionization chamber and a fiber-optic radiation sensor incorporating an organic scintillator. From the results, we could obtain the Bragg peak and the spread-out Bragg peak of proton beams without quenching effects induced by the scintillator, and these results were in good agreement with those of the ionization chamber. We also measured the Cerenkov radiation generated from the fiber-optic Cerenkov radiation sensor as a function of the dose rate of the proton beam.

0 Reads | 1 Citations
2012
Jun
07
Published new article




Article

Fiber-optic Cerenkov radiation sensor for proton therapy dosimetry

Published: 07 June 2012 by The Optical Society in Optics Express

doi: 10.1364/oe.20.013907

In proton therapy dosimetry, a fiber-optic radiation sensor incorporating a scintillator must undergo complicated correction processes due to the quenching effect of the scintillator. To overcome the drawbacks of the fiber-optic radiation sensor, we proposed an innovative method using the Cerenkov radiation generated in plastic optical fibers. In this study, we fabricated a fiber-optic Cerenkov radiation sensor without an organic scintillator to measure Cerenkov radiation induced by therapeutic proton beams. Bragg peaks and spread-out Bragg peaks of proton beams were measured using the fiber-optic Cerenkov radiation sensor and the results were compared with those of an ionization chamber and a fiber-optic radiation sensor incorporating an organic scintillator. From the results, we could obtain the Bragg peak and the spread-out Bragg peak of proton beams without quenching effects induced by the scintillator, and these results were in good agreement with those of the ionization chamber. We also measured the Cerenkov radiation generated from the fiber-optic Cerenkov radiation sensor as a function of the dose rate of the proton beam.

0 Reads | 16 Citations
2012
May
31
Published new article




Article

High-Sensitive Fiber-Optic pH Sensor Using Neutral Red Immobilized in Porous Sol-Gel Film

Published: 31 May 2012 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2012.21.3.223

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2012
May
14
Published new article




Article

Integral T-Shaped Phantom-Dosimeter System to Measure Transverse and Longitudinal Dose Distributions Simultaneously for ...

Published: 14 May 2012 by MDPI in Sensors

doi: 10.3390/s120506404

A T-shaped fiber-optic phantom-dosimeter system was developed using square scintillating optical fibers, a lens system, and a CMOS image camera. Images of scintillating light were used to simultaneously measure the transverse and longitudinal distributions of absorbed dose of a 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm2. Each optical fiber has a very small sensitive volume and the sensitive material is water equivalent. This allows the measurements of cross-beam profile as well as the percentage depth dose of small field sizes. In the case of transverse dose distribution, the measured beam profiles were gradually become uneven and the beam edge had a gentle slope with increasing depth of the PMMA phantom. In addition, the maximum dose values of longitudinal dose distribution for 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm2 were found to be at a depth of approximately 15 mm and the percentage depth dose of both field sizes were nearly in agreement at the skin dose level. Based on the results of this study, it is anticipated that an all-in-one phantom-dosimeter can be developed to accurately measure beam profiles and dose distribution in a small irradiation fields prior to carrying out stereotactic radiosurgery.

0 Reads | 2 Citations
2011
Oct
01
Published new article




Article

Evaluation of the dosimetric characteristics of a radiophotoluminescent glass dosimeter for high-energy photon and elect...

Published: 01 October 2011 by Elsevier BV in Radiation Measurements

doi: 10.1016/j.radmeas.2011.08.021

We aimed to evaluate the suitability of a glass dosimeter (GD) for high-energy photon and electron beams in experimental and clinical use, especially for radiation therapy. We examined the expanded dosimetric characteristics of GDs including dose linearity up to 500 Gy, uniformity among GD lots and for individual GDs, the angular dependence, and energy dependence of 4 therapeutic x-ray qualities. In addition, we measured the dosimetric features (dose linearity, uniformity, angular dependence, and energy dependence) of the GD for electron beams of 10 different electron energy qualities. All measurements with the exception of dose linearity for photon beam were performed in a water phantom. For high-energy photon beams, dose linearity has a linear relationship for a dose ranging from 1 to 500 Gy with the coefficient of determination; R2 of 0.998. The uniformity of each GD of dose measurements was within ±0.5% for four GD lots and within ±1.2% for 80 GDs. In terms of the effects of photon beam angle, lower absorbed doses of within 1.0% were observed between 60° and 105° than at 90°. The GD energy dependence of 4 photon beam energy qualities was within ±2.0%. On the other hand, the result of the dose linearity for high-energy electron beams showed well fitted regression line with the coefficient of determination; R2 of 0.999 between 6 and 20 MeV. The uniformity of GDs exposed to the nominal electron energies 6, 9, 12, 16, and 20 MeV was ±1.2%. In terms of the angular dependence to electron beams, absorbed doses were within 2.0% between 60° and 105° than at 90°. In evaluation of the energy dependence of the GD at nominal electron energies between 5 and 20 MeV, we obtained responses between 1.1% and 3.5% lower than that for a cobalt-60 beam. Our results show that GDs can be used as a detector for determining doses when a high-energy photon beam is used, and that it also has considerable potential for dose measurement of high-energy electron beam. Highlights► We aimed to evaluate the suitability of a glass dosimeter for high-energy photon and electron beams for radiation therapy. ► Our results show that GDs can be used as a detector for determining doses when a high-energy photon beam is used. ► Also, it has considerable potential for dose measurement of high-energy electron beam.

2 Reads | 1 Citations
2010
Jun
01
Published new article




Article

Measurements of Relative Depth Doses Using Fiber-Optic Radiation Sensor and EBT Film for Brachytherapy Dosimetry

Published: 01 June 2010 by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Nuclear Science

doi: 10.1109/TNS.2010.2043263

In this study, we have fabricated a fiber-optic radiation sensor using an organic scintillator for brachytherapy dosimetry. Organic scintillators are made from a polystyrene base with wavelength-shifting fluors, and they do not disturb the radiation field due to their tissue or water-equivalent characteristics in a wide range of energies. The fiber-optic radiation sensor developed for this study provides a fast real-time response and convenient usage for brachytherapy dosimetry. For more accurate measurement, we have measured Cerenkov light using a dummy fiber and avoided dose measurement errors arising from high dose gradients in brachytherapy dosimetry. The Cerenkov light has been eliminated using a modified subtraction method. Also, the relative depth dose without the dose generated from Cerenkov lights is measured and compared with the results obtained using conventional EBT dosimetry films.

3 Reads | 5 Citations
2010
Jan
30
Published new article




Article

Measurement of relative dose irradiated from a Co-60 source using a scintillating fiber-optic dosimeter

Published: 30 January 2010 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2010.19.1.052

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2008
Nov
30
Published new article




Article

Measurements of temperature distribution using an infrared optical fiber during radiofrequency ablation

Published: 30 November 2008 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2008.17.6.397

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2008
Nov
30
Published new article




Article

Measurements of relative depth dose rates for a brachytherapy Ir-192 sourceusing an organic scintillator fiber-optic rad...

Published: 30 November 2008 by The Korean Sensors Society in Journal of Sensor Science and Technology

doi: 10.5369/jsst.2008.17.6.462

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2008
Nov
01
Published new article






Infrared fiber-optic sensor for non-contact temperature measurements

Published: 01 November 2008 by Institute of Electrical and Electronics Engineers (IEEE) in 2008 3rd International Conference on Sensing Technology (ICST 2008)

doi: 10.1109/icsenst.2008.4757156

In this study, we have developed a non-contact temperature sensor using a silver halide optical fiber for medical endoscopic usage. We have measured an infrared radiation which is transferred by a silver halide optical fiber from a heat source using a thermal optical power-meter and a thermopile sensor. To increase the amount of infrared radiation through the silver halide optical fiber and to the infrared sensors, optical devices such as an infrared collimator and a focusing lens are used. The relationships between the temperatures of a heat source and the measured output signals are determined. The measurable temperature range of a fiber-optic temperature sensor is from 30 to 60°C. It is expected that a non-contact temperature sensor using an infrared optical fiber can be developed for medical and industrial usages based on the results of this study.

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2008
Nov
01
Published new article






Measurements of Cerenkov radiations in a scintillating fiber-optic dosimeter using a photodiode and a charge-coupled dev...

Published: 01 November 2008 by Institute of Electrical and Electronics Engineers (IEEE) in 2008 3rd International Conference on Sensing Technology (ICST 2008)

doi: 10.1109/icsenst.2008.4757151

Usually, two kinds of light signals such as scintillating and Cerenkov light are generated in a fiber-optic dosimeter when a high energy electron beam is irradiated. The objectives of this study are to measure, characterize and remove a Cerenkov light generated in a scintillating fiber-optic dosimeter. The intensity of Cerenkov light is measured and characterized as a function of incident angle of electron beam from a linear accelerator, as a function of electron beam energy, and as a function of electron beam size using a photodiode amp system and a charge-coupled device. Also, a subtraction method using a background optical fiber without a scintillator is investigated to remove a Cerenkov light.

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2015
Jul
13
Conference participation




Sang Hun Shin participated at conference 4th International Symposium on Sensor Science.

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