• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.927-934
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• 2022

This study attempted to find out the degree of agreement between ultrasound image findings along with analysis of attenuation index and scatter distribution index values within tissues through quantitative measurement analysis using liver ultrasound images. From August 2022 to October 2022, liver ultrasound was performed on 45 patients who were suspected of having fatty liver and who received a prescription for liver ultrasound. As a result of the study, as a result of analyzing the agreement between the ultrasound image findings and the tissue attenuation index, the Kappa value was 0.82 (p<0.05), showing a very high agreement between the two examination methods. In addition, as a result of the agreement analysis between the ultrasound image findings and the scatter distribution index in the tissue, the Kappa value was 0.642 (p<0.05), showing high agreement between the two examination methods. At the time of fat liver prediction, the use of liver ultrasound findings and quantitative ultrasonography techniques, such as intra-tissue attenuation index and intra-tissue scatter distribution index, may be helpful in determining the degree of progression of fatty liver patients.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.351-356
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• 2012

Ultrasonic cavitation is a physical phenomenon that generates and collapses microbubbles in media (mainly fluids) under conditions of strong ultrasonic irradiation. In this study, changes in the ultrasonic acoustic characteristics of bubble clouds in relation to ultrasonic irradiation were observed by the quantitative evaluation of cavitation yields. Concave-type single ultrasonic transducers with center frequencies of 500 kHz and 1.1 MHz were used to produce cavitation, and 2.25 MHz interference ultrasonic waves that would traverse any bubble clouds generated were used to analyze the cavitation. The parameters used for the evaluation of cavitation yields (changes in the center frequency, attenuation characteristics, and the propagation time of penetrating waves) were analyzed in relation to the cavitation-generating conditions (irradiation intensity, excitation signal, and center frequency). On the basis of these results, correlations between the changes in the center frequency and irradiation intensity were identified. Although the correlation coefficient was low, notable changes were observed in the center frequency under certain irradiation conditions. Attenuation trends in the interference ultrasonic waves showed high correlations with all the irradiation conditions, and it was noted that these trends were not affected by the forms of cavitation generated. No differences in the propagation time were observed among different irradiation conditions. These findings suggest that bubble yields can be quantitatively evaluated effectively by evaluating the diverse irradiation conditions and that such a quantitative evaluation could be used to study the basic cavitation phenomenon occurring in high-intensity ultrasonic wave treatment.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.2
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• pp.94-98
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• 2009

Acupuncture is a treatment method that originated more than 3,000 years ago in China and is practiced in most of the world. Acupuncture became the most popular complementary and alternative medicine modality. Ultrasound is useful for research and educational purposes, visualizing needle insertion at acupuncture points, especially next to vulnerable structures such as nerves or the pleura. Additionally, ultrasound is an ideal imaging method for evaluation the biomechanical effects of needle manipulation on tissue and has the distinctive advantage of yielding both images of tissue morphology and biomechanical information. Elastography take aim at quantifying a mechanical response or the mechanical property of tissues from a mechanical stimulus, generated internally or externally. Therefore, the combination of ultrasound and elastography analyses allows quantitative assessment of dynamic changes in the structure of human connective tissue.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.112-121
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• 1994

This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to $10{\mu}m$ extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.959-966
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• 2010

Quantitative ultrasound analysis provides fundamental information of various ultrasound parameters using spectral information of the short-gated radiofrequency(RF) data. Therefore, accurate extraction of spectral information from backscattered RF signal is crucial for further analysis of medical ultrasound parameters. In this paper, we propose two techniques for calculating a more accurate power spectrum which are based on the phase-compensation using the normalized cross-correlation to minimize estimation errors due to phase variations, and the weighted averaging technique to maximize the signal-to-noise ratio(SNR). The simulation results demonstrate that the proposed method estimates better results with 10% smaller estimation variances compared to the conventional methods.

• Journal of Biomedical Engineering Research
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• v.22 no.1
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• pp.101-108
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• 2001

본 논문에서는 뇨실금 환자들에 대한 지원 기술의 일환으로 인체에 무해하고 비침습적인 초음파를 이용하여 배뇨시기를 알려주기 위한 재택용 뇨의 경보기용 뇨량검출 센서의 개발과 이를 이용한 방광 벽간거리와 뇨량과의 상관관계에 관하여 연구하였다. 개발된 센서는 인체내에 침투력이 가장 좋은 중심 주파수가 2.25 MHz인 초음파를 사용하여 분해능을 높여 오차를 감소시킬 수 있는 구조로 설계하였다. 이 센서를 이용하여 방광전.후벽간의 거리를 검출하여 이로부터 뇨량을 정량적으로 측정하기 위한 기초 실험을 실시하였다. 기초실험은 건강한 성인 남자 3명을 대상으로 초음파 뇨량검출 센서를 이용한 초음파 RF 반사신호 획득장치와 초음파 진단기에 의한 2가지 방법으로 이루어졌고 그 결과 뇨량과 벽간거리와의 사이에는 높은 상관성이 있음을 확인할 수 있었다. 결론적으로, 실험 결과를 토대로 하여 제작된 초음파 뇨의 센서를 부착한 초음파 뇨의 경보 시스템은 뇨실금 환자로 하여금 배뇨시기를 알려주는 경보 시스템으로 보건.복지적인 측면에서 현대사회에 기여할 공헌도가 매우 클 것이라 생각된다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.373-378
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• 2004

하모니 영상은 초음파의 비선형 전파 과정에서 발생된 하모닉 성분을 영상화 한다. 하모닉 영상은 초음파에 비선형적으로 반응하는 초음파 조영제를 사용하여 하모닉 성분의 발생을 최대화 하고 있다. 일반적으로 현재 임상적으로 사용되는 하모닉 영상은 2차 고주파 성분을 사용한 것을 의미한다. 2차 하모닉 영상은 주파수의 상승으로 공간 분해능이 향상된다. 초음파 조영제를 이용하는 경우 서브 하모닉, 울트라 하모닉의 발생도 유의할 것으로 기대되지만 이에 대한 연구는 거의 없는 실정이다. 서브 하모닉은 상대적으로 2차 하모닉보다 전파 과정에서 감쇠 효과가 작기 때문에 심부의 영상에 유리하다 서브 하모닉 및 울트라 하모닉 성분 검출은 초음파 변환기의 대역폭에 대한 제한을 2차 하모닉에 비해 상대적으로 덜 받는다. 본 연구에서는 진단용 초음파에 의해 초음파 조영제에서 방사하는 하모닉 성분의 크기를 시뮬레이션 하였다. 수치해석은 Gilmore Equation을 이용하였으며, 초음파 조영제의 탄성 효과는 무시하였다. 초음파 조영제의 크기와 초음파의 MI에 따라 하모닉 성분의 크기를 정량적으로 비교하고, 서브 및 울트라 하모닉 영상의 구현에 대해 토의하였다.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.180-185
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• 2004

Conventional ultrasonic examination to detect micro and small surface cracks is based on the pulse-echo technique using a normal immersion focused transducer with high frequency, or an angle-beam transducer generating surface waves. It is difficult to make an automatic ultrasonic system that can detect micro and small surface cracks and position in a large structure like steel and ceramic rolls, because of the huge data of inspection and the ambiguous position data of the transducer. In this study, a high-precision scanning acoustic microscope with a 10MHz large-aperture transducer has been used to assess the existence, position and depth of a surface crack from the real-time A, B, C scans obtained by exploiting the ultrasonic diffraction. The ultrasonic method with large aperture transducer has improved the accuracy of the crack depth assessment and also the scanning speed by ten times, compared with the conventional ultrasonic methods.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.1004-1010
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• 1992

In recent years, along with the development of ultrasonic probe with wide frequency range, the digitization of measuring instrument, and the development of operating process technics, it is possible to analyze ultrasonic pulse in frequency range. In this paper, applying to flaw model the ultrasonic spectroscopy method that can analyze ultrassonic pulse in frequency range, we examine the possibility of quantification of flaw and apply its result to the void and seperation in LSI package. Consequently, by using the change in frequency distribution and central frequency of sltrasonic pulse detected from flaw, the estimation of shape, size, and depth of flaw is possible. The change in central frequency is changed minutely by the sample materals and position of flaw, but changed mainly by the shape and size of flaw. And we can quantify the shape and size of flaw in LSI pakcage using the experimental result through flaw model.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.490-490
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• 2023

위상배열초음파검사(PAUT)는 기존 초음파검사에서 획득할 수 있었던 A-scan의 결과와 달리, 관로 내부로 진입하지 않고도 부식에 의한 강관 손상 정도를 정량적인 시각적 데이터로 파악할 수 있는 검사 기술이다. 관내부 직접조사가 가능한 상수도 강관을 대상으로 직접조사와 PAUT를 비교한 결과, PAUT는 높은 정확도와 신뢰성을 보여주었다. 또한, 강관 내부의 부식검사에서는 PAUT를 적용함으로써 관체의 부식 면적, 부식 최대 깊이, 부식 위치를 넓은 범위에서 신뢰성 높은 검사 및 결과 도출이 가능하였다. 이러한 결과는 PAUT 기술이 강재 구조물의 다양한 부식 문제를 신속하게 파악하고 해결하는 데 기여할 수 있음을 의미한다. 따라서, 본 검사 기법은 상수도 관로의 강재 진단 및 점검에 있어 높은 신뢰성 및 효율성을 보여 주는 진단기법으로써 다양한 강재 시설물의 평가에 활용성이 클 것으로 판단된다. 이에 따라 PAUT는 상수도 시설물뿐만 아니라 다양한 시설물에서도 높은 활용 가능성을 가질 것으로 예상된다.