• 한국유체기계학회 논문집
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• 제12권3호
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• pp.31-37
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• 2009

This paper presents a implantable intrathecal drug infusion pump for pain control in cancer patients. This device consists of micropump module, drug reservoir module and control module. The micropump module using cam-follower mechanism composed of small-sized four cams and four followers. Each followers is driven by a cam and liquid is discharged by a sequential reciprocal motion of the followers. The advantage of this structure is that it allows the pump to be clean and valveless. The drug reservoir module composed of drug chamber, gas chamber and diaphragm. The control module composed of battery, wireless communication unit and controller. To design a small-sized, low power pump some analysis were performed to determine the design parameters. To verify the feasibility of the experiment, a prototype was manufactured and its operating characteristics were investigated. Experimental results were in accordance with the expected results obtained from analysis.

• 센서학회지
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• 제27권2호
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• pp.99-104
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• 2018

A micro electromagnetic actuator with high vibration efficiency is proposed for use in an implantable hearing device. The actuator, which can be implanted in the middle ear, consists of membranes based on the stainless steel 304 (SUS-304), and other components. In conventional actuators, in which a thick membrane and a silicone elastomer are used, the size reduction was difficult. In order to miniaturize the size of the actuator, it is necessary to reduce the size of the actuation potion that generates the driving force, resulting in reduction of the electromagnetic force. In this paper, the electromagnetic actuator is further miniaturized by the metal membrane and the vibration amplitude is also optimized. The actuator designed according to the simulation results was fabricated by using micro-electro-mechanical systems (MEMS) technology. In particular, a $20{\mu}m$ thick metal membrane was fabricated using the erosion process, which reduced the length of the actuator by more than $400{\mu}m$. In the experiments, the vibration displacement characteristics of the optimized actuator were above 400 nm within the range of 0.1 to 1 kHz when a current of $1mA_{rms}$ was applied to the coil.

• Journal of Pharmaceutical Investigation
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• 제25권2호
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• pp.117-123
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• 1995

For the effective administration of narcotic antagonist, the application of sustained release implantable systems with biodegradable polyphosphazene was examined. Using poly[(diethyl glutamate)-co-(ethyl glycinate) phosphazene], the implantable devices containing naloxone hydrochloride were prepared and in vivo implantation studies were carried out subcutaneously in rat and rabbit with this preparation for the biocompatibility and pharmacokinetics. The histological finding in rats at initial time period was the inflammation that occurred focally around the implants, but they were showed subsequent mild and limited chronic inflammations and the irreversible changes such as necrosis and degeneration of the muscle or connective tissues were not observed. Therefore the placebo and naloxone implants are considered to be biocompatible formulations histologically. In pharmacokinetic studies, the release of naloxone from the naloxone implants into blood plasma was maintained in 192 hours, but the initial burst effect was observed. If this problem was solved, the application for the narcotic antagonist sustained release systems can be expected.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.136-140
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• 1997

In this paper, we proposed a implantable middle ear system using FM transmission and receiving method which has higher detection efficiency than that of AM method. And a new shape of vibrating transducer which is more efficiently vibrate than the conventional type is designed. This tranducer consist of coil and small T-type cylindrical permanent magnet. We investigated and compared the differences between conventional methods and proposed methods by quantitive analysis. We proved them by experiment.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.150-154
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• 2019

The objective of this study is to monitor the radiation doses delivered to a cardiac implantable electronic device (CIED) by comparing the absorbed doses calculated by a commercial treatment planning system (TPS) to those measured by an in vivo dosimeter. Accurate monitoring of the radiation absorbed by a CIED during radiotherapy is necessary to prevent damage to the device. We conducted this study on three patients, who had the CIED inserted and were to be treated with radiotherapy. Treatment plans were generated using the Eclipse system, with a progressive resolution photon optimizer algorithm and the Acuros XB dose calculation algorithm. Measurements were performed on the patients using optically stimulated luminescence detectors placed on the skin, near the CIED. The results showed that the calculated doses from the TPS were up to 5 times lower than the measured doses. Therefore, it is recommended that in vivo dosimetry be conducted during radiotherapy for CIED patients to prevent damage to the CIED.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.1063-1066
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• 1999

The delay of cardiac depolarization wave detection in the conventional pacemakers or AICD (automatic implantable cardioverter/ defibrillator, or ICD) has been overlooked. However, it is known that the delay may cause hemodynamic problems and may prevent the proper operation of a new automatic feature, automatic capture verification, that is to be appeared in the near-future devices. In order to reduce the effects of the delay, a delay prevention algorithm was developed and tested by applying three human electrograms. The algorithm set the sensing threshold just above the measured noise level to reduce the detection delay. It is found that the low threshold was able to reduce the delay by 20msec(average) In most cases. The implementation results showed reliability and efficacy of the algorithm, and the algorithm could be applicable to the existing hardware and software of the conventional pacemakers and AICD without any significant modifications.

• Journal of Chest Surgery
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• 제46권3호
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• pp.202-207
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• 2013

Background: The role of totally implantable central venous port (TICVP) system is increasing. Implantation performed by radiologist with ultrasound-guided access of vein and fluoroscope-guided positioning of catheter is widely accepted nowadays. In this article, we summarized our experience of TICVP system by surgeon and present the success and complication rate of this surgical method. Materials and Methods: Between March 2009 and December 2010, 245 ports were implanted in 242 patients by surgeon. These procedures were performed with one small skin incision and subcutaneous puncture of subclavian vein. Patient's profiles, indications of port system, early and delayed complications, and implanted period were evaluated. Results: There were 82 men and 160 women with mean age of 55.74. Port system was implanted on right chest in 203, and left chest in 42 patients. There was no intraoperative complication. Early complications occurred in 11 patients (4.49%) including malposition of catheter tip in 6, malfunction of catheter in 3, and port site infection in 2. Late complication occurred in 12 patients (4.90%). Conclusion: Surgical insertion of TICVP system with percutaneous subclavian venous access is safe procedures with lower complications. Careful insertion of system and skilled management would decrease complication incidence.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.445-450
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• 2012

We have developed an implantable wireless sensor for real time pressure monitoring of blood circulation system. MEMS (micro-electro-mechanical system) technology was adopted as a sensor development method. The sensor is composed of photolithographically patterned inductors and a distributed capacitor in gap between the inductors. A resulting LC resonant system produces its resonant frequency in range of 269 to 284 MHz at 740 mmHg. To read the resonant frequency changed by blood pressure variation, we developed a custom readout system based on a network analyzer functionality. The bench-top testing of the pressure sensors showed good mechanical and electrical functionality. A sensor was implanted into tibial artery of farm pig, and interrogated wirelessly with accurate readings of blood pressure. After 45 days, the sensor's electrical response and histopathology were studied with good frequency reading and biocompatibility.

• Journal of Korean Neurosurgical Society
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• 제57권3호
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• pp.152-158
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• 2015

Objective : The purpose of this study to develop new deep-brain stimulation system for long-term use in animals, in order to develop a variety of neural prostheses. Methods : Our system has two distinguished features, which are the fully implanted system having wearable wireless power transfer and ability to change the parameter of stimulus parameter. It is useful for obtaining a variety of data from a long-term experiment. Results : To validate our system, we performed pre-clinical test in Parkinson's disease-rat models for 4 weeks. Through the in vivo test, we observed the possibility of not only long-term implantation and stability, but also free movement of animals. We confirmed that the electrical stimulation neither caused any side effect nor damaged the electrodes. Conclusion : We proved possibility of our system to conduct the long-term pre-clinical test in variety of parameter, which is available for development of neural prostheses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.407-410
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• 2002

As a part of electro-mechanical totally implantable artificial heart, a transcutaneous energy transmission system has been developed. By mutual magnetic induction between the first coil on the skin and the subcutaneously implanted second coil, the system transfers electrical power through the skin. This research aimed a minimizing the size of the implanted part as well as maximizing the transfer efficiency. When an air gap is 1$\sim$2cm, voltage gain and current gain low and it is hard to transfer energy due to large leakage flux. That is, the required input voltage and input current must be large compared with the output voltage and output current, respectively, This paper research the inverter topology and the control method in order to increase the voltage gain and the current gain. For this purpose, this inverter employs double tune to compensate the large leakage inductance of primary and secondary of the transcutaneous transformer. And the output energy of transcutaneous energy transmission system supply for Lithium-ion battery charger.