• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.390-398
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• 2022

Ultrasound examination using ultrasound equipment is an ultrasound device that images human organs using sound waves and is used in various areas such as diagnosis, follow-up, and treatment of diseases. However, if the quality of ultrasound equipment is not guaranteed, the possibility of misdiagnosis increases, and the diagnosis rate decreases. Accordingly, The Korean Society of Radiology and Korea society of Ultrasound in Medicine presented guidelines for quality management of ultrasound equipment using ATS-539 phantom. The DenseNet201 classification algorithm shows 99.25% accuracy and 5.17% loss in the Dead Zone, 97.52% loss in Axial/Lateral Resolution, 96.98% accuracy and 20.64% loss in Sensitivity, 93.44% accuracy and 22.07% loss in the Gray scale and Dynamic Range. As a result, it is the best and is judged to be an algorithm that can be used for quantitative evaluation. Through this study, it can be seen that if quantitative evaluation using artificial intelligence is conducted in the qualitative evaluation item of ultrasonic equipment, the reliability of ultrasonic equipment can be increased with high accuracy.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.491-496
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• 2018

The purpose of this study is to analyze the noise spectra in DWI (diffusion-weighted imaging) pulse sequences of 1.5 Tesla and 3.0 Tesla MRI, The ACR (American College of Radiology) phantom and noise spectrum were analyzed by FFT (fast Fourier transform) and TFFT (temporal frequency analysis) using WavePad sound editor version 8.13 (NCH software, Greenwood Village, CO, USA). Noise spectra, FFT and TFFT were analyzed for laboratory 1.5Tesla and 3.0Tesla DWI MR pulse sequences. The noise threshold of the frequency amplitude in the FFT and TFFT at 3.0Tesla compared to 1.5Tesla was between 1.5Tesla and -6 dB, and between 3.0Tesla and 0 dB, the DWI pulse sequence for the patient's noise reduction was appropriately MR examination needs to be applied.

• The Journal of the Acoustical Society of Korea
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• v.23 no.4
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• pp.268-273
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• 2004

A method of reflection-transmission type ultrasonic inverse scattering image was presented using linearly arrayed transducers in inner surface of half-cylinder. In this method, to reduce the number of data, the mirror effect using a reflector behind object and pulse wave with finite frequency band, To verify the proposed method, a computer simulation was performed for organic phantom specimen, As the results. it was verified that the reconstructed image was satisfactory even when the limitation view angle was limited to around 30 deg.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1E
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• pp.38-44
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• 2010

This paper is based on our comments and proposed amendments to the documents, Annex A, Phantom for determining Maximum Depth of Penetration, and Annex B, Local Dynamic Range Using Acoustical Test Objects 87/400/CDV. IEC 61391-2 Ed. 1.0 200X, prepared by IEC technical Committee 87; Ultrasonics. The documents are concerned with the influence of microstructure of reference target material on the ultrasonic backscattering. Previous works on the attenuation due to backreflection and backscattering of reference target materials are reviewed. The drawback to the use of ungraded stainless steel and metallic materials without microstructural data such as, crystal structure, basic acoustic data of sound velocity and attenuation, grain size, roughness and elastic constants has been discussed. The analysis suggested that the insightful conclusion can be made by differentiating the influence arising from target size and microstructure on the backscattering measurements. The microstructural parameters are associated with physical, geometrical, acoustical and mechanical origins of variation with frequency. Further clarification of such a diverse source mechanisms for ultrasonic backscattering would make the target material and its application for medical diagnosis and therapy simpler and more reliable.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.975-984
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• 2022

Since a linear transducer has an area of interest equal to the length of the transducer, the area of interest can be expanded using the virtual convex function installed in the device.However, it was thought that the change in the direction of the ultrasonic sound velocity according to the change in the visual area of interest would affect the image quality, so this was objectively confirmed. For this study, image evaluation and SNR·CNR of the phantom for ultrasound quality control were measured. As a result, in the phantom image evaluation, both images were able to identify structures in functional resolution, grayscale, and dynamic range. However, it was confirmed that the standard image was excellent in the reproducibility of the size and shape of the structure. As a result of SNR·CNR evaluation, SNR·CNR of most trapezoidal images was low, except for structures at specific locations. In addition, through the statistical analysis graph, it was further confirmed that the SNR and CNR for each depth decreased as the size of the cystic structure decreased. Through this study, it was confirmed that the use of the function has the advantage of providing a wide visual area of interest, but it has an effect on the image quality. Therefore, when using the virtual convex function, it is judged that the examiner should use it in an appropriate situation and conduct various studies to acquire high-quality images and to improve the understanding and proficiency of the equipment.

• The Journal of the Acoustical Society of Korea
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• v.39 no.6
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• pp.576-584
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• 2020

In order to obtain basic information for using polyvinyl alcohol (PVA) gel as a tissue mimicking phantom for temperature visualization, the temperature change characteristics due to the focused ultrasound were examined for different concentration of PVA. To obtain the basic acoustic characteristics, the speed of sound, the attenuation coefficient, and the density depending on the PVA concentration were measured, and the thermodynamic characteristics, such as thermal conductivity and heat capacity, were measured. The range of temperature rising in the vicinity of the focal point due to the focused ultrasound was observed using a thermochromic film that changes color at 30 degree or more, and the discolored area was obtained by image processing of the recorded image. As the concentration of PVA increases in the given range of 2 wt% ~ 16 wt%, the area that rises above 30 degree inside the gel increases linearly. It is confirmed that the discolored area increases as the power applied to the focused ultrasonic transducer increases. These results showed good agreement with the simulation results using the finite element method.