• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.751-759
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• 2022

Currently, ultrasound examination for diagnostic ultrasound and health examination purposes is widely used, and it is showing an increasing trend due to the application of health insurance. However, the risk of ultrasound has not been clearly identified so far, and in this study, surface and deep temperature changes according to frequency and mode were measured by using a tissue mimicking phantom and TI and MI values were compared. A simulated phantom was manufactured by adding a small amount of kappa-caraginan powder with acoustic characteristics similar to that of the human body and potassium chloride for solidification, and the change of surface and depth temperature was measured using a surface thermometer and a probe thermometer. As a result, the convex probe using low frequency showed a higher temperature increase than the linear probe using high frequency, so there was a significant difference, and the temperature increase was the highest on the surface, and the depth of 1cm showed a temporary temperature increase, but there was no significant temperature change. There was no change in the deep temperature of 5 cm to 15 cm, and the TI and MI values did not change during the test time. Since only the surface temperature rose during the 15-minute test and there was no temperature change in the core, so it is not expected to show a temperature change that is harmful to the human body. However, it is thought that prolonged examination of one area may cause temperature rise, so it should be avoided.

• The Journal of the Acoustical Society of Korea
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• v.33 no.5
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• pp.291-299
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• 2014

To probe the temperature elevation effect caused by ultrasound, a tissue mimicking phantom was newly suggested. A carrageenan gel was adopted to realize not only the required transparency for visualization but also acoustic characteristics similar to human tissue. To visualize the temperature elevation inside phantom, thermochromic film with a critical temperature of discoloration was introduced. Acoustic characteristics of the tissue mimicking phantom were examined when the concentrations of carrageenan and sucrose changed. As the results, the attenuation coefficient of the phantom could be controlled in the range of 0.44~0.49 dB/cm/MHz, and the acoustic impedance in the range of 1.52~1.77 Mrayls. We could control the acoustic characteristics of the phantom by different concentration of carrageenan and sucrose, and it was possible to examine the temperature elevation caused by ultrasound in the phantom. The suggested method was verified by noninvasively visualizing the temperature elevation due to planar and focused ultrasound using the fabricated phantom.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.21-30
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• 2014

The temperature change due to focused ultrasound in dissipative acoustic medium is very important because it provides us much information. To measure the temperature change inside of the dissipative acoustic medium non-invasively, we adopt a temperature sensitive film which has thermochromic particles with critical temperature of $30^{\circ}C$. As a dissipative acoustic medium, agar layer is chosen in the study. The temperature change due to the ultrasound was measured depending on the concentration of the sugar in the agar layer. The color change on the film due to the ultrasound was investigated when the concentration of sugar was from 25% to 40%. As the result, there were rapid increases of discolored area on the film within 2~5 second after the ultrasound driving and the increasing rates decreased after the period. To compare the simulation results were also shown. However in the simulated result, the discolored areas linearly increased from start to 10 seconds. The reason of the differences between the experimental results and simulated ones is that the change of thermal conductivity and heat capacity of the medium were not considered in the simulation program.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.369-370
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• 2004

초음파의 조차에 의한 인체내부의 온도상승의 측도로 열지수(thermal index)가 사용되고 있으며, 이는 주파수 및 음향파워에 의존한다. 초음파 조사에 의한 인체내부의 온도상승을 평가하는데 사용되는 재료를 조직 모사 물질이라 한다. 본 논문아사는 단위 음향파워에 대한 온도 변화인 열 감도(thermal sensitivity)를 새로이 정의하였으며, 이 물리량으로 조직모사물질의 성능을 평가 할 수 있다는 것을 제안하고자 한다.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.895-900
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• 2019

Ultrasound is known to be harmless to the human body and is widely used in obstetrics and gynecology to confirm the diagnosis and development status of fetus. Diagnosis Although long - term use of ultrasound may cause changes in body temperature, studies on the uterine temperature changes due to ultrasound have been lacking. The purpose of this study was to investigate the change of temperature according to ultrasonic scanning time using a self - produced uterine model phantom. Ultrasound equipment and a 4MHz convex probe were used to construct the uterine model phantom similar to the human uterus using acrylic and pig uterus, which are tissue equivalents. Three probe type thermometers were installed to measure the inside of the acrylic water tank, the uterus, and the atmospheric temperature. The temperature of the uterine phantom was ascertained by measuring the temperature of the subject for 6 hours, 361 times. In this study, the possibility of human body temperature elevation due to ultrasound could be confirmed and this study will be used as the basic data of ultrasonic heat absorption study.

• Journal of the Korean Society of Radiology
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• v.6 no.3
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• pp.201-206
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• 2012

Effect of prenatal ultrasound diagnosis have serious damage for the possibility has been reported very low. Long time ultrasound scan can rise the temperature in body tissues and affect the physical. Changes in body temperature have been studied with ultrasound scan time. Fetal ultrasonography were evaluated without the influence of time. The findings, ultrasound scan time in 40 minutes the temperature was reduced. 50 minute tissue temperature rose more than $1^{\circ}C$. If within 40 minutes of ultrasound to be safe guess

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.532-535
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• 2009

In this study, the fatty acid methyl ester was prepared from the vegetable oil by inducing ultrasound energy. The ultrasound energy was applied to the esterification reaction for heating and stirring effects. Ultrasonic induction results in the shortened reaction time and brings the increase of the methyl ester yield. However, the continuous introduction of ultrasound during the esterification reaction results in temperature increase, then the over-heating of reaction temperature was ineffective. Therefore, the system temperature was controlled at constant temperature state with the cooling circulation. The ultrasound induction reaction had the fatty acid methyl ester yield of 93% at the reaction time was 30 minutes, faster than the traditional esterification process.

• 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.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.523-528
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• 2015

In this study, we evaluated the heating characteristics of single sonication and superposed two low-intensity ultrasonic sonication. Compare the results, the superposed sonication was showed a superior thermal effect than single sonication. And the maximum temperature was increased as 120-150%. The starting time of temperature rising has been shortened in superposed sonication. In addition, the time up to the maximum temperature has been shortened, too. In generally, as the ultrasonic intensity is higher, the more surface damage is occurred. However, in the case of superposed sonication, the same thermal effect had be confirmed without surface damage. Through the results of the study, we thought that the superposed sonication will be able to reduce the intensity of the ultrasonic treatment. And, by using the low-intensity, the more safe and more effect therapy will be possible in therapeutic ultrasound application.

• Journal of the Korean Physical Therapy Association
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• v.8 no.2
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• pp.33-40
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• 1987