1.Research on wavelength matching of therapeutic laser fiber.
Chinese Journal of Medical Instrumentation 2014;38(4):290-314
Medical laser adopts optical fibers as spread media, using laser energy for the purpose of diagnostics and therapeutics. The corresponding industry standard is YY/T 0758-2009 General requirements for therapeutic laser fiber, which requires manufacturers to offer applicable wave length (or spectrum range) of the fiber, and the corresponding minimum transmission efficiency of the wave length. This research focuses on the matching of therapeutic laser fiber and laser source, to support and emphasize the importance and reasonability of relative requirements in YY/T 0758-2009.
Equipment Design
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Lasers
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Optical Fibers
2.Comparison of Time Domain OCT and Spectrum Domain OCT for Retinal Nerve Fiber Layer Assessment.
Bu Ki KIM ; Dong Wook LEE ; Min AHN ; Nam Chun CHO
Journal of the Korean Ophthalmological Society 2009;50(10):1539-1547
PURPOSE: To compare retinal nerve fiber layer (RNFL) thickness obtained with Stratus optical coherence tomography (OCT) and Cirrus OCT. METHODS: Sixty-one normal eyes were evaluated with Stratus and Cirrus OCT on the same day, and the RNFL thicknesses measured by the two OCT machines were compared. The correlation between the two data sets was obtained using Pearson's correlation coefficient. The correlation between RNFL thickness and the difference in data measured by the two OCT machines was then assessed. RESULTS: The average RNFL thickness was significantly higher with Stratus OCT by 6.54+/-4.48 micrometer (p=0.0008). A strong correlation was present between the two RNFL thickness data sets (r=0.883), and the difference between Stratus and Cirrus values tended to increase as RNFL thickness increased. CONCLUSIONS: RNFL thickness measurements in normal eyes scanned with Cirrus OCT correlate well with Stratus OCT measurements. Average RNFL thickness was significantly higher with Stratus OCT, and as the RNFL thickness increased, the difference between Stratus and Cirrus values increased.
Eye
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence
3.A Comparison of Retinal Nerve Fiber Layer Thickness Measured Using Five Different Optical Coherence Tomography Devices
Youn Gon LEE ; Young Hoon HWANG
Journal of the Korean Ophthalmological Society 2018;59(3):261-267
PURPOSE: To compare circumpapillary retinal nerve fiber layer (RNFL) thicknesses as measured using five different optical coherence tomography (OCT) devices. METHODS: RNFL thickness was measured in 32 healthy eyes of 32 subjects using a Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA), Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany), Topcon DRI OCT (Topcon, Tokyo, Japan), RS-3000 Advance OCT (NIDEK, Aichi, Japan), and RTVue-100 (Optovue, Fremont, CA, USA). Global and quadrant (superior, nasal, inferior, and temporal) RNFL thicknesses were compared using repeated measures analysis of variance, and the agreement among devices was determined using Bland-Altman analyses. RESULTS: The global RNFL thickness was greatest when measured using the Topcon DRI OCT, with a mean value of 107.5 µm. The mean global RNFL thicknesses measured using the RTVue-100, RS-3000 Advance OCT, and Spectralis OCT were 104.9 ± 8.4, 104.4 ± 9.4, 102.5 ± 8.9 µm, respectively. The Cirrus HD-OCT presented the thinnest RNFL measurement, with a mean value of 97.7 ± 8.7 µm (p < 0.01). A similar pattern was found for the quadrant RNFL thicknesses (p < 0.01). Differences in the global RNFL thicknesses among the devices ranged from 0.5 to 9.9 µm. The limits of agreement of the global RNFL thicknesses evaluated by Bland-Altman analyses ranged from 6.8 to 19.6 µm. CONCLUSIONS: RNFL thicknesses measured using five different OCT devices were not interchangeable and there was a wide limit of agreement. When interpreting RNFL thickness values determined by different devices, caution is advised.
Glaucoma
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence
4.Fabrication and Optimization of a Fiber-optic Dosimeter for Proton Beam Therapy Dosimetry.
Kyoung Won JANG ; Dong Hyun CHO ; Wook Jae YOO ; Jeong Ki SEO ; Bongsoo LEE ; Eui Jung HWANG ; Dongho SHIN ; Sung Yong PARK
Korean Journal of Medical Physics 2010;21(1):29-34
In this study, we have fabricated a fiber-optic dosimeter for a proton beam therapy dosimetry. We have measured scintillating lights with the various kinds of organic scintillators and selected the BCF-12 as a sensor-tip material due to its highest light output and peak/plateau ratio. To determine the optimum diameter of BCF-12, we have measured scintillating lights according to the energy losses of proton beams in a water phantom. Also, we determined the adequate length of organic scintillator by measuring scintillating lights according to the incident angles of proton beam. Using an optimized fiber-optic dosimeter, we have measured scintillating lights according to the dose rates and monitor units of proton accelerator.
Light
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Optical Fibers
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Organothiophosphorus Compounds
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Proton Therapy
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Protons
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Water
5.Quantitative Analysis of Retinal Nerve Fiber Layer Thickness Profile in Myopic Eyes.
Tae Geun SONG ; Young Cheol YOO ; Ha Bum LEE
Journal of the Korean Ophthalmological Society 2009;50(12):1840-1846
PURPOSE: To investigate peripapillary retinal nerve fiber layer (RNFL) thickness profiles associated with myopia. METHODS: One hundred and twenty-seven normal eyes of 67 Korean adults were divided into three groups by spherical equivalent. All subjects were tested with fast RNFL scans of Stratus optical coherence tomography. The angular locations of superior and inferior maximal thickness points in relationship to a reference line drawn horizontally though the center of the scan circle were calculated from the raw data of scanned images (angle alpha, angle beta). Differences of angle alpha and angle beta were compared among the three groups. RESULTS: Angle alpha and angle beta were significantly different in three groups (ANOVA, p<0.001, respectively). Angle alpha and angle beta were also significantly different among the three groups for excluded eyes with tilted discs. CONCLUSIONS: The points of superior and inferior maximal peripapillary RNFL thickness were significantly different in three groups divided by spherical equivalent. As myopia becomes more severe, superior and inferior maximal peripapillary RNFL thickness points are located closer to the fovea.
Adult
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Eye
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Humans
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Myopia
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence
6.Analysis of Localized Retinal Nerve Fiber Layer Defects not Detected by Optical Coherence Tomography.
Young Sang HAN ; Seung Youn JEA ; Su Jin KIM ; Joo Eun LEE ; Ji Eun LEE ; Gi Hong KOO
Journal of the Korean Ophthalmological Society 2009;50(4):558-564
PURPOSE: To analyze localized RNFL defect cases that were identified in retinal nerve fiber layer (RNFL) fundus photographs but not in optical coherence tomography (OCT). METHODS: Analysis of OCT scans and images was performed for 14 eyes (17 locations) that showed localized RNFL defects in RNFL fundus photographs but not in RNFL thickness average analysis. RESULTS: With respect to the range of RNFL defects, 41.2% were less than 10degrees, 47.0% were 11 to 20degrees, and 11.8% were 21 to 30degrees. In 71.4% of the RNFL cases the defects were less than 10degrees and the decrease of RNFL thickness was not readily observable on the OCT scan images. In all cases of RNFL defects in the 11 to 30degrees range the decrease in RNFL thickness could be assessed on the OCT scan images. Nonetheless, the decrease of RNFL thickness could not be seen on the OCT analysis images in which the results of the RNFL thickness made through an automated computer algorithm were displayed. CONCLUSIONS: The range of localized RNFL defects that were difficult to detect with OCT consisted of those cases that were almost less than 20degrees. The limitations of the OCT scan itself in patients with RNFL with an angular width defect less than 10degrees and the problems of RNFL thickness analysis processing in patients with an angular width of 11 to 30degrees may decrease the sensitivity of OCT in diagnosing RNFL defects.
Eye
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Humans
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence
7.Fabrication and Characterization of a One-dimensional Fiber-optic Dosimeter for Electron Beam Therapy Dosimetry.
Kyoung Won JANG ; Dong Hyun CHO ; Sang Hun SHIN ; Wook Jae YOO ; Jae Hun JUN ; Bongsoo LEE ; Joo Hyun MOON ; Byung Gi PARK
Korean Journal of Medical Physics 2008;19(4):285-290
In this study, we have fabricated a one-dimensional fiber-optic dosimeter for electron beam therapy dosimetry. Each fiber-optic dosimeter has an organic scintillator with a plastic optical fiber and it is embedded and arrayed in the plastic phantom to measure one-dimensional high energy electron beam profile of clinical linear accelerator. The scintillating lights generated from each sensor probe are guided by plastic optical fibers to the multi-channel photodiode amplifier system. We have measured one-dimensional electron beam profiles in a PMMA phantom according to different field sizes and energies of electron beam. Also, the isodose and three-dimensional percent depth dose curves in a PMMA phantom are obtained using a one-dimensional fiber-optic dosimeter with different electron beam energies.
Electrons
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Light
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Optical Fibers
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Particle Accelerators
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Plastics
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Polymethyl Methacrylate
8.Analysis of Retinal Nerve Fiber Layer Thickness in Patients With Superior Segmental Optic Hypoplasia.
Jeong Won SEO ; In Won PARK ; Yun Suk CHUNG
Journal of the Korean Ophthalmological Society 2009;50(1):139-144
PURPOSE: To analyze the thickness of the peripapillary retinal nerve fiber layer (RNFL) in patients with superior segmental optic hypoplasia (SSOH) using optical coherence tomography (OCT). METHODS: Ten eyes of 10 patients with SSOH and 20 eyes of 20 subjects as normal control were evaluated. The peripapillary RNFL thickness measured by Stratus OCT was compared between the two groups. RESULTS: The mean RNFL thickness was significantly different between SSOH patients (72.35+/-14.77 micrometer) and normal subjects (111.61+/-6.62 micrometer) (p<0.001). The extent to which the RNFL thickness was below 5 percentile of normal subjects on the TSNIT graph was from the 41.7+/-15.53 to 110.1+/-7.47 scan number, which corresponded mainly with the superior nasal region. Moreover, in a clock-hour analysis, the peripapillary RNFL thic kness of the SSOH patients decreased significantly from 10 o'clock to 6 o'clock compared to normal subjects (p<0.01). CONCLUSIONS: Peripapillary RNFL thickness in patients with SSOH was reduced in the superior, nasal, and inferior regions. Further studies involving larger populations of patients should be performed to verify these findings.
Eye
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Humans
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence
9.Retinal Nerve Fiber Layer Volume Measurements in Normal Children Using Spectral Domain Optical Coherence Tomography.
Dong Eik LEE ; Joong Won SHIN ; Han Woong LIM ; Yong Un SHIN ; Min Ho KANG ; Hee Yoon CHO ; Min Cheol SEONG
Journal of the Korean Ophthalmological Society 2016;57(5):800-807
PURPOSE: To measure retinal nerve fiber layer (RNFL) volume in normal children using spectral domain optical coherence tomography (SD-OCT). METHODS: This study included 79 eyes of 54 normal children between 4 and 15 years of age evaluated from February 2012 to November 2012. All participants underwent ocular examination and 3D-disc scanning using SD-OCT. RNFL volume was calculated between 2.5 and 5 mm diameter circles using the length, width, and height of each pixel derived from the RNFL thickness map with Matlab software. The relationship between RNFL volume and thickness was analyzed. RESULTS: The RNFL volumes of the mean total, superior, nasal, inferior, and temporal areas were 1.48 ± 0.09 mm3, 0.45 ± 0.04 mm3, 0.29 ± 0.04 mm3, 0.46 ± 0.03 mm3, and 0.29 ± 0.04 mm3, respectively. Comparing RNFL volume and conventional circumpapillary RNFL thickness measured using built-in software, a strong correlation between mean total, superior, and inferior areas (R = 0.980, 0.953 and 0.932, respectively) and a moderate correlation between the nasal and temporal areas were observed (R = 0.545 and 0.514, respectively). The negative correlations between RNFL thickness and RNFL volumes of the mean total, superior, nasal, inferior, and temporal areas and age were not significant (p > 0.05). CONCLUSIONS: This study reports RNFL volume measured from RNFL thickness map analysis in normal children. These data regarding RNFL volume of normal children may provide useful information for diagnosis and monitoring of pediatric glaucoma.
Child*
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Diagnosis
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Glaucoma
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Humans
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Nerve Fibers*
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Retinaldehyde*
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Tomography, Optical Coherence*
10.Comparison of Retinal Nerve Fiber Layer Thickness Measured by Spectral-Domain and Time-Domain Optical Coherence Tomography.
Juhyang LEE ; In Seok SONG ; Yu Jeong KIM ; Yong Jae CHA ; Ki Bang UHM
Journal of the Korean Ophthalmological Society 2012;53(1):103-110
PURPOSE: To compare retinal nerve fiber layer (RNFL) thickness measured by time domain (Stratus) and spectral domain (3D) optical coherence tomography (OCT). METHODS: Sixty-nine normal subjects and 92 glaucoma patients were included in the present study. Peripapillary RNFL thickness was measured with Stratus fast RNFL scan and 3D optic disc cube scan on the same day. The relationship between RNFL thickness measurements of the two OCTs were evaluated using a Pearson's correlation analysis. A Bland-Altman plot was used for the comparison of Stratus-OCT and 3D-OCT. RESULTS: In all subjects, average, superior, and inferior quadrant RNFL thicknesses measured by Stratus-OCT were thicker than those measured by 3D-OCT. In contrast, temporal and nasal quadrant RNFL thicknesses measured by 3D-OCT were thicker than those measured by Stratus-OCT. Although there were absolute value differences in RNFL thicknesses, high correlation was observed between Stratus-OCT and 3D-OCT (average: r = 0.897, temporal quadrant: r = 0.728, superior quadrant: r = 0.811, nasal quadrant: r = 0.678, and inferior quadrant: r = 0.905). Bland-Altman plots showed that Stratus-OCT values were greater than 3D-OCT values with relatively high RNFL thickness and the opposite with low RNFL thickness. CONCLUSIONS: For thicker RNFL, Stratus-OCT measurements tend to be greater than 3D-OCT, while for thinner RNFL, 3D-OCT measurements tend to be greater than Stratus-OCT. This difference must be taken into account if comparing measurements made with a Stratus-OCT to the measurements of a 3D-OCT.
Glaucoma
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Humans
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Nerve Fibers
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Retinaldehyde
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Tomography, Optical Coherence