• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.751-759
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• 2023

Breast ultrasonography is difficult to image in fatty breasts and to find micro-calcification, but the discovery of micro-calcification is very important for breast cancer screening. Among the color Doppler artifact of ultrasound, twinkle artifact mainly occur on strong reflectors such as stones or calcification in images, and evaluation methods using them are clinically being used. In this study, we are conducting experiments on the color Doppler settings of ultrasound equipment, such as repetition frequency, ensemble, persist, wall filtering, smoothing, linear density, and dissociation value, by producing a breast simulation phantom using the largest amount of calcium phosphate among breast implants. The purpose of this study was to improve the contrast of twinkle artifact in breast ultrasound examinations and to maximize their use in clinical practice. As a result, the pulse repetition frequency occurred in the range of 3.6 kHz to 7.2 kHz, and did not occur above 10.5 kHz. For ensembles, twinkle artifact occurred in all sizes of calcification under low conditions, and in threshold settings, the twinkle artifact increased slightly only under 80 to 100 conditions, and did not occur in 1 mm size calcification. Persist, wall filter, smoothing, and line density settings did not have much meaning in the setting variable because conditions did not increase by condition, and pulse repetition frequency, ensemble, and thresholds had the greatest impact on the twinkling artifact image. This study is expected to help examiners select optimal conditions to effectively increase twinkle artifact by adjusting color Doppler settings.

• Journal of IKEEE
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• v.18 no.4
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• pp.544-551
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• 2014

This paper suggests an algorithm to measure low-level radiation by radiation measuring devices, and the other algorithm to improve reaction speed of the device to better respond to dramatic changes in radiation amount. The former algorithm to improve the accuracy of measuring low-level radiation takes advantage of a dual window radiation measurement method which is based on accumulated average of pulses gathered by a radiation measuring sensor. The latter algorithm is to enhance reaction speed of a measuring device to more sensitively react to dramatic changes in radiation amount by adopting a dual window radiation measurement method which analyzes data patterns newly put into for six seconds. To verify the suggested algorithms, a hardware-which consists of sensor and high-voltage generator, controller, charger and power supply circuit, wireless communication part, and display part-was used. Tests conducted on the dual window radiation measurement method as used in the suggested algorithm have proved that accuracy improves to measure low-level radiation of 5uSv/h, and linearity also gets better. Other tests were conducted to see whether the suggested algorithm enhances the reaction speed of a radiation measuring device so that the device responds better to dramatically changing radiation amount. The experimental results have shown meaningful changes in numbers after six seconds. Therefore, the conclusions are made that the algorithm enhances the reaction speed of the device.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.143-148
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• 2016

The purpose of this study was examined the measurement error factor on AMARES of jMRUI method for magnetic resonance spectroscopy (MRS) quantitative analysis by skilled and unskilled observer method and identified the reason of independent observers. The Point-resolved spectroscopy sequence was used to acquired magnetic resonance spectroscopy data of 10 weeks male Sprague-Dawley rat liver. The methylene protons ($(-CH_{2-})n$) of 1.3 ppm and water proton ($H_2O$) of 4.7 ppm ratio was calculated by LCModel software for using the reference data. The seven unskilled observers were calculated total lipid (methylene/water) using the jMRUI AMARES technique twice every 1 week, and we conducted interclass correlation coefficient (ICC) statistical analysis by SPSS software. The inter-observer reliability (ICC) of Cronbach's alpha value was less than 0.1. The average value of seven observer's total lipid ($0.096{\pm}0.038$) was 50% higher than LCModel reference value. The jMRUI AMARES analysis method is need to minimize the presence of the residual metabolite by identified metabolite MRS profile in order to obtain the same results as the LCModel.

• Journal of the Korean Institute of Telematics and Electronics
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• v.3 no.1
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• pp.18-23
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• 1966

An experimental study of a steel plate thickness gauge by means of the measurements of backscatered gamma-rays has been carried out. The difference between this and other methods is that this method does not include any shilding matterials in the detecting probe, because the primary radiations and the backscattered radiations are detected simultaneously by an NaI (TI) scintillating crystal, and the activity of the Co-60 source used is low enough. In this thickness gauge, the thickness of the steel plates can be read directly on the counting ratemeter scale. The optimum conditions in the source-to-detector distance, window width of the analyzer, energy and strength of the gamma-ray source were found experimentally. The results have shown that the accuracy of the gauge was about $\pm$3% in the range of 3 to 8mm thickness. This gauge can be used to detect the pits or corrosions on the inner walls of the steel pipes.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.253-259
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• 2014

Large volume of $6{\times}6{\times}12mm^3$ CdZnTe ${\gamma}$-ray detector was fabricated with CdZnTe single crystals grown by Traveling Heater Method (THM) to evaluate the energy resolution of 662 keV in $^{137}Cs$. Hole tailing effect which originated from the large mobility difference in electron and hole degrade energy resolution of radiation detector and its effects become more severe for a large volume detectors. Generally, single carrier collection technique is very useful method to remove/minimize hole tailing effect and thereby improvement in energy resolution. Virtual Frisch-grid technique is also one of single charge collection method through weighting potential engineering and it is very simple and easily applicable one. In this paper, we characterized CZT detector grown by THM and evaluated the effectiveness of virtual Frisch-grid technique for a high energy gamma-ray detector. The proper position and width of virtual Frisch-grid was determined from electric field simulation using ANSYS Maxwell ver. 14.0. Energy resolution of 2.2% was achieved for the 662 keV ${\gamma}$-peak of $^{137}Cs$ with virtual Frisch-grid CdZnTe detector.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.2
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• pp.7-12
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• 2019

Purpose: During the pelvic radiation therapy, it is performed with controlling bladder volume because the range of irradiation is changed depending on the bladder volume. Therefore in this study, we evaluate the accuracy of BVI by tracing the change of bladder volume using ultrasonic pulse diagnosis equipment(BVI 6100, Medical supply Co. LTD) Material and Methods: From January 2017 to September 2018, 19 patients who received pelvic radiation therapy at Pusan National University Hospital were included. To treat the patient, we compared that the bladder volume obtained from the BVI and the bladder volume obtained from the CBCT image then we evaluated for significance. Results: There was a significant correlation of r=0.773, BVI and CBCT in the whole volume section. However, based on the bladder volume in the RTP Image the p value was shown to be 0 at 125~175cc and lower than 0.05 at 175~275cc, And more than 0.05 at 275~375cc. Conclusions: In this study, the patient whose bladder volume is above than 275cc, there is a significance of bladder volume between BVI and CBCT image. However, we could make a decision to be undermined the reliability of BVI measurement in the case of the patient with emptied his urine. Therefore, it is possible to acquire a significant value for 175~275cc patients to use the correction value of BVI and the appropriate tolerance of volume.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.577-580
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• 2000

The aim of this paper is to develop a high stable measuring device for radioactive pulses. The device consists of a high voltage supply unit using a fly-back converter principle, and a pulse detection unit for gamma-rays and neutrons. The high voltage supply unit designed can generate DC voltage up to 1,500v at 5V-input, and have a series voltage regulator to maintain the output voltage constantly, resulting in less than 1.63% of voltage regulation. The pulse detection parts consists of an active integrator, a pole-zero circuit, and a 3-stage amplifier of 60 dB, and its frequency bandwidth is from 37 Hz to 300 kHz. From the experimental results, it is confirmed that the measuring device can count at least 10,000 pulses in a second.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.465-468
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• 2001

An objection of this study is to develop a high stable analytic system of radioactive pulses. The proposed system consists of an amplifying circuit with 60dB gain, a programmable power supply unit which can generate DC voltage up to 1, 500V, and a digital signal processor. Pulse height distribution in accordance with pulse counts is important data in analyzing radioactive pulses. In this study, AD convertor (12bit, l00ns) and DSP (TMS 320C31-60) are used to analyze the pulse height, and the analytic system is designed to be operated in PC-networking.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.227-232
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• 1998

하나로 1차 배관에서 중성자를 측정하고 발생 원인을 분석하였으며, 이를 통하여 중성자 계측 계통을 이용하여 핵연료 파손을 감시할 수 있는 가능성을 검토하였다. 중성자 측정에는 BF$_3$비례 계수관을 이용하였고, 1차 배관의 주 방사선원인 N-16에 의한 감마선 펄스의 영향은 무시 할 정도로 작았다. 중성자의 발생 원인을 규명하기 위해 원자로 정지 전후에 중성자 계수율의 변화를 측정하였다. 편자로의 정상 운전시 1차 배관에서 발생되는 중성자는 물속의 중수소가 고에너지 감마선을 흡수하여 방출하는 광중성자와 핵연료의 표면 오염에 의해 발생된 지발 중성자라고 가정하여 원자로 정지 전후의 발생량 변화를 계산하였다. 계산 결과와 측정값을 비교하여 1차 배관 주변에서 측정된 중성자 가운데 지발 중성자가 약 70 %, N-16에 의한 광중성자가 약 30%임을 확인하였다. 핵연료의 표면 오염 정도로 발생하는 지발 중성자도 민감하게 측정되므로, 이러한 지발 중성자 계측법이 핵연료의 손상 여부를 알아낼 수 있는 유용한 방법임을 확인할 수 있었다.

• Journal of Radiation Protection and Research
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• v.21 no.2
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• pp.91-98
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• 1996

An optimized method for determining beta-emitting $^{241}Pu$ in the presence of alpha-emitting nuclides was developed using a liquid scintillation counting system. Pulse shape analysis (PSA) level was set using pulse-shape discrimination method and the $^{241}Pu$ counting channel was adjusted for maximum value of figure of merit using the 241pu standard source. The volume of scintillant was determined for the maximum value of counting efficiency. This optimized method has been applied to environmental samples to measure concentration of $^{241}Pu$ in soils and mosses. Also it has been identified the origin of Pu deposited in Korea from the activity ratio of $^{241}Pu/^{239,\;240}Pu$.