approx. 100 to 150 words) The vibration of an ultrasonic transducer generates ultrasonic wave for ultrasonic test. To get proper ultrasonic wave for the ultrasonic test the ultrasonic transducer vibrates properly. If it is possible to watch the vibration at the surface of an ultrasonic transducer, it is possible to check the propriety. But there is no way to see or to show the vibration of an ultrasonic transducer directly until now. We use a laser vibrometer to get a vibration signal at a point of an ultrasonic transducer surface and scan over the surface to get full vibration information. The full vibration information composes [x, y, t] 3 dimensional data array and it is possible to show the surface shape of the ultrasonic transducer at each time t from the data. By increasing or decreasing the time t of the data continuously an animation of the vibration can be showed. We can see the vibration pattern and can check the condition of the ultrasonic transducer by viewing the animation. Also defects of the ultrasonic transducer can be detected from the animation.

Specific tissue lengths or volumes in x-ray images are measured for diagnostic and therapeutic purposes. Measurements are used to make clinical decisions; however, the accuracy of these measurements has not been studied. In this study, based on the sources of uncertainty, an SI-traceable length standard phantom and an x-ray imaging system calibration method are proposed. The uncertainty in the length of the fabricated standard phantom is determined using a toolmaker's microscope. The sources of uncertainty in an x-ray imaging system, such as magnification, pixel-to-millimeter unit conversion, and penumbra effect, are considered, and the lengths of the phantom before and after imaging system calibration were compared. The maximum deviation of length measurements with and without calibration is (-0.11 ± 0.10) and (-3.37 ± 0.15) mm (k = 2, 95% level of confidence), respectively. The proposed phantom and calibration method can be used for calibrating x-ray images and obtaining their length correction values. Furthermore, length correction values are expected to be useful for diagnosis and treatment planning, where precise length measurements are essential.

Physical phantoms have been widely used for performance evaluation of magnetic resonance imaging (MRI). Although there are many kinds of physical phantoms, most MRI phantoms use fixed configurations with specific sizes that may fit one or a few different types of radio frequency (RF) coils. Therefore, it has limitations for various image quality assessments of scanning areas. In this article, we report a novel design for a truly customizable MRI phantom called the LEGO-compatible Modular Mapping (MOMA) phantom, which not only serves as a general quality assurance phantom for a wide range of RF coils, but also a flexible calibration phantom for quantitative imaging. The MOMA phantom has a modular architecture which includes individual assessment functionality of the modules and LEGO-type assembly compatibility. We demonstrated the feasibility of the MOMA phantom for quantitative evaluation of image quality using customized module assembly compatible with head, breast, spine, knee, and body coil features. This unique approach allows comprehensive image quality evaluation with wide versatility. In addition, we provide detailed MOMA phantom development and imaging characteristics of the modules.

A photoplethysmography (PPG) platform integrated with a miniaturized force-regulator is proposed in this study. Because a thermo-pneumatic type regulator maintains a consistent contact-force between the PPG probe and the measuring site, a consistent and stable PPG signal can be obtained. We designed and fabricated a watch-type PPG platform with an overall size of 35 mm × 19 mm. In the PPG measurement on the radial artery wrist while posture of the wrist is changed to extension, neutral, or flexion, regulation of the contact-force provides consistent PPG measurements for which the variations in the PPG amplitude (PPGA) was 7.2 %. The proposed PPG platform can be applied to biosignal measurements in various fields such as PPG-based ANS monitoring to estimate nociception, sleep apnea syndrome, and psychological stress.

In this study, we report the first experimental realization of an ultrathin (0.14λ, λ = 1.482 mm means wavelength at 1 MHz in the water medium) subwavelength focusing acoustic lens that can surpass the Rayleigh diffraction limit (0.61λ/NA, NA means numerical aperture). It is termed a Super-Oscillatory Acoustic Lens (SOAL), and it operates in the megasonic range. The SOAL represents an interesting feature allowing the achievement of subwavelength focusing without the need to operate in close proximity to the object to be imaged. The optimal layout of the SOAL is obtained by utilizing a systematic design approach, referred to here as topology optimization. To this end, the optimization formulation is newly defined. The optimized SOAL is fabricated using a photo-etching process and its subwavelength focusing performance is verified experimentally via an acoustic intensity measurement system. From these measurements, we found that the proposed optimized SOAL can achieve superior focusing features with a Full Width at Half Maximum (FWHM) of ~0.40λ/NA ≃ 0.84 mm (for our SOAL, NA = 0.707) with the transmission efficiency of 26.5%.

This study proposes a skin analysis device using a truncate hollow cone (THC) probe for measuring both transepidermal water loss (TEWL) and skin hardness. Because skin health is closely related to the epidermal barrier function and skin mechanical property, it is important to measure their biophysical indicators at the same time, to understand skin conditions and diagnose skin disorders such as atopic dermatitis and systemic sclerosis. Previous skin analyzers, however, required different probes with different protocols for each biophysical indicators, which makes the measurement inconvenient and increases the measurement uncertainty. The present device consists of a THC probe equipped with humidity and force sensors, and an actuator that simultaneously measure both TEWL and skin hardness which indicate the integrity of the epidermal barrier function and the skin mechanical property, respectively. Using artificial reference skins, the prototype device showed the TEWL with a sensitivity and linearity of 0.011 (%/s)/(g/m2/h) and 99.5%, and the hardness with 0.075 N/(Shore 00) and 97.6%, respectively, which are within the appropriate range for the properties of human skin. The on-body measurement of five subjects showed that the proposed device could measure both the TEWL and skin hardness without any crosstalk from each other. The proposed device has great potential for in-depth analysis of the health status of the skin which could indicate various skin diseases.

An international comparison of ultrasound power measurements was conducted among the ultrasound laboratories of the Korea Research Institute of Standards and Science (KRISS), the National Metrology Institute of Japan (NMIJ) and the National Institute of Standards (NIS, Egypt). The measurand for comparison is the electro-acoustic radiation conductance G, which is defined as the amount of ultrasound power divided by the square of the input signal voltage to the transducer. The reference device is an ultrasonic transducer, model number KRISS-2MHz-14LN, manufactured by KRISS using a Lithium-Niobate (LiNbO3) piezoelectric single crystal. This comparison, reference number KN.U-K2, was piloted by KRISS, including the preparation of the protocol and the reference device, and the analysis of measurement results by the participants. This paper reports the comparison results.

A thin-film resistance temperature detector (RTD) array is proposed to measure the temperature distribution inside a phantom. HIFU (high-intensity focused ultrasound) is a non-invasive treatment method using focused ultrasound to heat up a localized region, so it is important to measure the temperature distribution without affecting the ultrasonic field and heat conduction. The present 25 mu m thick PI (polyimide) film is transparent not only to an ultrasonic field, because its thickness is much smaller than the wavelength of ultrasound, but also to heat conduction, owing to its negligible thermal mass compared to the phantom. A total of 33 RTDs consisting of Pt resistors and interconnection lines were patterned on a PI substrate using MEMS (microelectromechanical systems) technology, and a polymer phantom was fabricated with the film at the center. The expanded uncertainty of the RTDs was 0.8 K. In the experimental study using a 1 MHz HIFU transducer, the maximum temperature inside the phantom was measured as 70.1 degrees C just after a HIFU excitation of 6.4 W for 180s. The time responses of the RTDs at different positions also showed the residual heat transfer inside the phantom after HIFU excitation. HIFU results with the phantom showed that a thin-film RTD array can measure the temperature distribution inside a phantom.

In this paper, we propose a phantom for calibrating devices in a method of quantifying and measuring the thickness of a thin film with ultrasonic diagnostic images, and have conducted analysis and experiments for verification. In order to solve the problem associated with variation of the width of the superposed pulse due to internal reflection in the thin layer, the width of a certain level (here, -20 dB) in the envelope of the superposed pulse signal is numerically calculated so that the width of the envelope and the thickness. Using this relation curve and the proposed phantom, it is possible to calibrate the ultrasonic thickness image which is quantified. PDMS phantoms with four different thicknesses were fabricated, and the behavior of the actual pulse echo signal was compared with the numerical results. The experiments and predictions showed similar behavior. Finally, based on these results, we propose a calibration procedure for the quantified image using this relation curve and the proposed phantom.

Blood pressure is one of the important vital signs for monitoring the medical condition of a patient. Automated NIBP(non-invasive blood pressure) monitoring devices calculate systolic and diastolic blood pressures from the oscillation in cuff pressure caused by a pulsation of an artery. To validate ...

In the manufacturing process of steel rod, a number of micro-scale defects occur along the axial direction on the surface of the rods. To prevent failures in advance, a method to detect the micro-scale cracks remaining on the surface of rod is required. This work employs an Electromagnetic acoustic transducer (EMAT) to evaluate the cracks of the wire rods with the noncontact Ultrasonic reverberation spectroscopy (URS). The resonance at the cross section of the cylindrical rods is generated by horizontally polarized shear waves driven in the circumferential direction. Through a series of URS experiments, changes in the resonant frequency, the amplitude of the resonant peak, and the attenuation of the ultrasonic reverberation were observed at intact and defected parts of specimens. The results showed that the URS technique may be one of the effective tools to detect the axial surface microcrack with its depth of a few tens of micrometers.

This research aimed to develop a simulator capable of oscillometric pressure pulses recorded from the participants for the validation of oscillometric noninvasive blood pressure (NIBP) devices. The simulator generates the pressure pulses to the cuff connected to NIBP devices depending on the oscillometric waveforms obtained from the participants. Device readings were compared with auscultatory references (systolic and diastolic blood pressures) of the participants. A total of 94 oscillometric waveforms from participants were used in the simulator for the validation of two automated NIBP devices (Omron HEM-7221 and UA-787Plus). For Omron HEM-7221, the differences between device readings and auscultation references for systolic and diastolic blood pressures were 2.82±7.27 and −4.74±6.73 mmHg, respectively. UA-787Plus showed differences of 3.26±5.69 and −3.53±6.61 mmHg, respectively. Although the number of individual measurements did not fulfill the ISO 81060-2 requirement for clinical validation, criterion 1, where the average of the difference and SD should be lower than ±5 and –8 mmHg, was fulfilled. Although the simulator still needs extensive comparative studies to be verified, it could be a potential candidate for a simple and robust tool for the validation and quality control of NIBP devices.

Blood pressure (BP) is one of the most important pieces of information to diagnose cardiovascular diseases but the measurement readings could be easily changed by various factors. If these readings are wrong, it may ultimately lead to a misdiagnosis. In addition, there is a problem when there are different devices used to read blood pressure because these devices may give different readings.

원격진료를 요하는 응급현장에서 사용을 위하여 1차원 배열 탐촉자를 손으로 조작하는 동안 변하는 방사빔의 위치를 추적하여 정적인 3차원 초음파영상을 구성하였다. 탐촉자에 고정된 모션센서의 병진운동 및 회전운동에 대한 정보를 기준직교좌표계로 변환하는 이론적 모델을 제시하였으며, 신호 증폭과 시리얼 통신을 위한 인터페이스 용도의 모듈을 상용의 센서를 사용하여 제작하였다. 실리콘 퍼티로 제작된 시험용 팬텀에 대한 B-모드의 동영상과 센서의 신호를 동기화하여 기록하였다. 동영상으로부터 주기적으로 추출한 B-모드 영상과 각 영상내의 픽셀 각각의 그레이 레벨을 이용하여 3차원 복셀의 그레이 레벨을 재구성하였다. 이 복셀의 데이터를 이용하여 3차원 영상과 임의단면의 B-모드 방식의 2차원 영상을 구성하였으며, 이 영상들은 시험용 팬텀의 형상과 잘 일치하였다. This paper describes the construction of a static 3D ultrasonography image by tracking the radiation beam position during the handy operation of a 1D array probe to enable point-of-care use. The theoretical model of the transformation from the translational and rotational information of the sensor mounted on the probe to the reference Cartesian coordinate system was given. The signal amplification and serial communication interface module was made using a commercially available sensor. A test phantom was also made using silicone putty in a donut shape. During the movement of the hand-held probe, B-mode movie and sensor signals were recorded. B-mode images were periodically selected from the movie, and the gray levels of the pixels for each image were converted to the gray levels of 3D voxels. 3D and 2D images of arbitrary cross-section of the B-mode type were also constructed from the voxel data, and agreed well with the shape of the test phantom.

Blood pressure is one of the most important vital signs used to monitor a patient’s medical condition and is widely measured in hospitals and at home. Automatic, non-invasive blood pressure (NIBP) monitoring devices measure systolic and diastolic blood pressures from the analysis of cuff pressure oscillations caused by periodic variations of blood pressure in an artery. Currently, clinical validation by comparing them to the auscultatory reference has been used to verify the performance of NIBP devices. However, there are presently no calibration methods for NIBP devices. Here, we propose an SI-traceable calibration method for oscillometric NIBP devices. The calibration system generates pressure-pulses at pre-determined cuff pressures, and with pre-determined amplitude, to the device-under-test. The uncertainty of each pulse is analyzed and used for the calculation of blood pressure (BP) uncertainty. The maximum uncertainty for systolic and diastolic BP using the newly developed calibration system is (0.74 and 0.60) mmHg (k = 2) depending on the pressure and amplitude of each pulse, as well as the number of pulses applied. The present method can be used for calibration of oscillometric NIBP devices.

In microfludic biosensor applications, many kinds of magnetic particles have been employed due to their bioaffinity property, so the appropriate manipulation of magnetic microparticles is important. In this work, we demonstrated the alignment of magnetic beads (diameter 2.8 μm) and nanowires (length ≤ 6 μm & diameter ≈ 50 nm) using ultrasonic standing wave (USW) in a steel-acrylic microfluidic channel (660 μm width) in the aim of concentrating them to a sensor area to enhance the performance of a sensor. Ultrasonic standing wave field generates the radiation force to concentrate microparticles at the pressure nodal planes. To generate a standing wave inside the channel, an ultrasound of 2.25 MHz resonance frequency was applied as a resonance frequency of the channel. Moreover, it was demonstrated here that the position of the aligned magnetic particles could be controlled by changing the applied frequency. These successful alignment and position control can be a milestone for future research which targets to improve the sensitivity of microfluidic sensors using magnetic particles.

Recently microfluidic manipulation of live cell has been attracting attention because it is necessary for fast and accurate bioassays of cells within miniaturized devices like a lab-on-a-chip. This work concerns the alignment, translocation and concentration of live cells in a microfluidic channel by utilizing an ultrasonic standing wave. Among many ultrasonic manipulation methods, the technique using frequency swept ultrasound which was proposed in a previous study offers excellent particle manipulation performance, but that has been demonstrated only for biocompatible polystyrene microspheres with several different diameters, not actual biological cells. However, the technique needs to be verified for real cells because sizes and properties are little different with each other. Thus, in this work, the feasibility of using the ultrasonic frequency sweep method to manipulate live Nb2-11 cells was investigated experimentally The cells were aligned in a plane, moved to one side of a channel, and finally filtered out by sending them to one outlet with ultrasound. The frequency region of the applied ultrasound was between 1.75 MHz and 3.05 MHz. From experimental results, the cell behavior showing perfect alignment, almost perfect translocation and hence considerable aggregation proved the feasibility of using the frequency sweep method though the force acting on the Nb2-11 cells are much smaller than the force acting on polystyrene beads due to the differences in their sizes and mechanical properties.

Regarding thin films in MEMS/NEMS structures, the exact evaluation of mechanical properties is very essential to enhance the reliability of their design and manufacturing. However, such methods as a tensile test and a resonance test, general methods to measure elastic moduli, cannot be applied to thin films since its thickness is so small. This work concerns guided wave based elastic modulus measurement method. To this end, guided wave excitation and detection system using a pulsed laser and a laser interferometry has been established. Also an elastic modulus extraction algorithm from the measured guided wave signal was developed. Finally, it was applied to actual thin film structures such as Ni-Si and Al-Si multilayers. From experimental results, we confirm that the proposed method has considerable feasibility to measure elastic properties of thin films. 한국소음진동공학회 2014년 추계학술대회