• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.55-66
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• 2018

Purpose In PET/CT exam, washed-out artifact could occur due to severe motion of the patient and high specific activity, it results in lowering not only qualitative reading but also quantitative analysis. Scatter limitation correction by GE is an algorism to correct washed-out artifact and recover the images in PET scan. The purpose of this study is to measure the threshold of specific activity which can recovers to original uptake values on the image shown with washed-out artifact from phantom experiment and to compare the quantitative analysis of the clinical patient's data before and after correction. Materials and Methods PET and CT images were acquired in having no misalignment(D0) and in 1, 2, 3, 4 cm distance of misalignment(D1, D2, D3, D4) respectively, with 20 steps of each specific activity from 20 to 20,000 kBq/ml on $^{68}Ge$ cylinder phantom. Also, we measured the distance of misalignment of foley catheter line between CT and PET images, the specific activity which makes washed-out artifact, $SUV_{mean}$ of muscle in artifact slice and $SUV_{max}$ of lesion in artifact slice and $SUV_{max}$ of the other lesion out of artifact slice before and after correction respectively from 34 patients who underwent $^{18}F-FDG$ Fusion Whole Body PET/CT exam. SPSS 21 was used to analyze the difference in the SUV between before and after scatter limitation correction by paired t-test. Results In phantom experiment, $SUV_{mean}$ of $^{68}Ge$ cylinder decreased as specific activity of $^{18}F$ increased. $SUV_{mean}$ more and more decreased as the distance of misalignment between CT and PET more increased. On the other hand, the effect of correction increased as the distance more increased. From phantom experiments, there was no washed-out artifact below 50 kBq/ml and $SUV_{mean}$ was same from origin. On D0 and D1, $SUV_{mean}$ recovered to origin(0.95) below 120 kBq/ml when applying scatter limitation correction. On D2 and D3, $SUV_{mean}$ recovered to origin below 100 kBq/ml. On D4, $SUV_{mean}$ recovered to origin below 80 kBq/ml. From 34 clinical patient's data, the average distance of misalignment was 2.02 cm and the average specific activity which makes washed-out artifact was 490.15 kBq/ml. The average $SUV_{mean}$ of muscles and the average $SUV_{max}$ of lesions in artifact slice before and after the correction show a significant difference according to a paired t-test respectively(t=-13.805, p=0.000)(t=-2.851, p=0.012), but the average $SUV_{max}$ of lesions out of artifact slice show a no significant difference (t=-1.173, p=0.250). Conclusion Scatter limitation correction algorism by GE PET/CT scanner helps to correct washed-out artifact from motion of a patient or high specific activity and to recover the PET images. When we read the image occurred with washed-out artifact by measuring the distance of misalignment between CT and PET image, specific activity after applying scatter limitation algorism, we can analyze the images more accurately without repeating scan.

• Journal of Life Science
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• v.14 no.3
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• pp.484-489
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• 2004

Artificial joint replacement is one of the major surgical advances of the 21th century. The primary purpose of a TKA (Total Knee Arthroplasty) is to restore normal knee Auction. Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from a chair or climbing stairs;(b) allow the same range of motion as an complete knee; and (c) provide adequate knee joint stability. Four individuals (2 peoples after surgery one year and 2 peoples after surgery three years) participated in this study. All they were prescreened for health and functional status by the same surgeon who performed the operations. Two days of accommodation practice occurred prior to the actual strength testing. The isometric strength (KIN-COM III) of the quadriceps and hamstring were measured at 60$^\circ$ and 30$^\circ$ of knee flexion, respectively. During isokinetic concentric testing, the range of motion was between 10$^\circ$ to 80$^\circ$ of knee flexion (stand-to-sit) and extension (sit-to-stand). for a given test, the trial exhibiting maximum torque was analyzed. A 16-channel MYOPACTM EMG system (Run Technologies, Inc.) was used to collect the differential input surface electromyographic (EMG) signals of the vastus medialis (VM), vastus lateralis(VL), rectus femoris (RF) during sit-to-stand and stand-to-sit tests. Disposable electrodes (Blue SensorTM, Medicotest, Inc.) were used to collect the EMG signals. The results were as follows; 1. Less maximum concentric (16% and 21% less for 1 yew man and 3 years mm, respectively) and isometric (12% and 29%, respectively) quadriceps torque for both participants. 2.14% less maximum hamstrings concentric torque for 1 year man but 16% greater torque for 3 years mm. However, 1 year man had similar hamstring isometric peak torque for both knees. 3. Less quadriceps co-contraction by 1 year man except for the VM at 10$^\circ$-20$^\circ$ and 30$^\circ$-50$^\circ$ range of knee flexion.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.4
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• pp.161-167
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• 2002

For the purpose of applying to micro-actuator, thermal properties and displacement of electrostrictive polyurethane(PU) elastomers have been measured. In order to understand an effect of PU component, crosslinking agent are controlled by 0.5 wt% and 1 wt%. DMPA and anther chain extenders were used. PU sample that chain extenders are DMPA is added NaOH for comprehension of effect of ionic groups. The deposited electrode sire on PU films is equal to acrylic holder size when the displacement was measured. Dynamic response according to frequency, displacement and recovery time according to PU thickness were measured. 1 wt% crosslinking agent contents PU samples have higher displacement and lower recovery time than 0.5 wt% crosslinking agent contents PU. If the PU thickness is increased, the actuating voltage for generating of same displacement is increased, too.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.41-47
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• 1990

최근 열에너지를 기계에너지로 변환이 가능한 신소재인 형상기억합금으로 제작된 새로운 형태의 actuator를 이용한 해저로봇의 개발에 관하여 많은 연구들이 행하고 있다. 저자들은 로봇의 모양을 실제 동물의 형태인 "게" 모양으로 하고, 로봇을 구동시키는 게의 다리의 모든 연결부분의 인공근육을 Ni-Ti계 형상기억합금 스프링 또는 와이어로 구성되어져 있으며, 마이크로 컴퓨터에 의하여 구동이 자유로이 조절이 가능한 게 형태의 모양 로봇을 실제의 1/20크기로 제작하였다. 이 로봇의 특징은 구조가 간단하고, 고강도, 고내식성 그리고 부드럽고 자유롭게 3차원적 동작이 가능하다는 것을 들 수 있다. 해저 로봇의 최종목표는 심해자원의 탐사 및 채굴이 이용하는 것이다. 따라서 본 연구에서는 그 가능성 및 기술적 문제 그리고 미래의 이러한 형상기억합금 로봇에 의한 심해자원 탐사를 위한 국제적인 협력의 필요성에 대하여 연구 검토하고자 한다. 검토하고자 한다.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.23 no.1
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• pp.25-33
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• 2016

Purpose: This study aimed to survey caregivers of patients with Neuromuscular Rare and Incurable Disease (NRID) using invasive home mechanical ventilator (HMV), in order to compare the incident rate of pneumonia by tracheal suction procedures used. Method: Participants were 99 family caregivers of NRID patients using HMV. Participants were given a questionnaire consisting of 12 demographic items, 10 items about disease and HMV related characteristics, 11 items about tracheal suction procedures, and 2 items about the incidence of pneumonia. Data were analyzed using chi-square tests and t-tests. Results: The items that predicted the incidence of pneumonia were "change of irrigation saline every suction" (p=.047), "use of aseptic catheter every suction" (p=.004), and "instillation of normal saline before suction" (p=.027). In addition, these items were 47.4%, 51.4%, and 38.8% respectively. Conclusion: Family members caring for NRID patients with invasive HMV should be educated about tracheal suction, especially the necessity of changing irrigation saline after every suction, using the aseptic catheter for every suction, and instillation of normal saline before suction. Medical personnel such as home care nurses should periodically check tracheal suction procedures, and re-educate family caregivers when necessary.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.725-728
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• 2008

An elbow orthosis with a pneumatic rubber actuator has been developed to assist and enhance upper limbs movements and has been examined for the effectiveness. The effectiveness of the elbow orthosis was examined by comparing muscular activities during alternate dumbbell curl motion wearing and not wearing the orthosis. The subjects participated in the experiment were younger adults in their twenties. The subjects were instructed to perform dumbbell curl motion in a sitting position wearing and not wearing orthosis in turn and a dynamometer was used to measure elbow joint torque outputs in an isokinetic mode. Orthosis was controlled using contractile muscle force that is measured from force sensor through cDAQ-9172 board. The air pressure of the pneumatic actuator was 0.3MPa the most suitable air pressure. For the analysis of muscular activities, Electromyography of the subjects was measured during alternate dumbbell curl motion. The experiment results showed that the muscular activities wearing the elbow orthosis were reduced. With this, we confirmed the effectiveness of the developed elbow orthosis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.244-247
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• 2005

Although several artificial disc designs have been developed for the treatment of discogenic low back pain and used clinically, biomechanical change with its implantation seldom studied. To evaluate the effect of artificial disc implantation on the biomechanics of lumbar spinal unit, nonlinear three-dimensional finite element model of L1-L5, S1 was developed and strain and stress of vertebral body and surrounding spinal ligaments were predicted. Intact osteoligamentous L1-L5, S1 model was created with 1-mm CT scan of a volunteer and known material property of each element were applied. This model also includes the effect of local muscles which was modeled with pre-strained spring elements. The intact model was validated with reported biomechanical data. Two models implanted with artificial discs, SB Charite or Prodisc, at L4/5 via anterior approach were also developed. The implanted model predictions were compared with that of intact model. Angular motion of vertebral body, force on spinal ligaments, facet joint contact force with $2\sim12$ Nm flexion-extension moment.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.39-45
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• 2007

This study was performed to induce the estrus in 9 anestrus Shih-tzu bitches by intramuscular injection of pregnant mare serum gonadotrophin (PMSG) 50IU/kg for 10 consecutive days and by intravenous injection of human chorionic gonadotrophin (hCG) 1,000IU/Head on Day 10. The day when the first injection of PMSG was counted as Day 0 of experiment. All of the bitches were monitored by vaginal discharges, displays the perineal region, vaginal swelling and male acceptances. The 9 bitches (100%) showed vaginal discharges and vaginal swelling, and were mated. The 5 bitches out of 9 bitches were pregnant (55.6%) and 4 bitches were non-pregnant (44.4%). The 3 bitches out of 5 pregnant bitches were spontaneously delivered (33.3%) and litter size were $1.66{\pm}1.15\;(1{\sim}3\;pups)$ pups. The 2 bitches were diagnosed as early embryonic death on days 38 and 41 after first injection of PMSG. These results indicated that rates of estrus induction, pregnancy and delivery were 100%, 55.6% and 33.3%, respectively, using PMSG and hCG.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.119-130
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• 2002

The nonlinear finite element program has been developed to analyze the design performance of an artificial hip prosthesis and long term behavior of a treated femur with stems made of composite material after cementless total hip arthroplasty(THA). The authors developed the three dimentional FEM models of femoral bone with designed composite stem which was taken with elliptic cross section of 816 brick elements under hip contact load and muscle farce in simulating single leg stand. Using the program, density changes, stress distributions and micromotions of the material femoral bone were evaluated by changing fiber orientation of stems for selected manufacturing method such as plate cut and bend mold. The results showed that the composite materials such as AS4/PEEK and T300/976 gave less bone resorption than the metallic material such as cobalt chrome alloy, titanium alloy and stainless steal. It was found that increasing the long term stability of the prosthesis in the femur could be obtained by selecting the appropriate ply orientation and stacking sequence of composite.

• Journal of Life Science
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• v.18 no.11
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• pp.1532-1537
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• 2008

The purpose of this study was to investigate the effect of different arthroplasty designs on knee kinematic and lower limb muscular activation for up-stair and down-stair movement. 3-D video analysis of whole body and joint kinematics and EMG analysis of quadriceps and hamstrings were conducted. One-way ANOVAs were used for statistical analyses (p=0.05). The single-radius group exhibited more arthroplasty limb quadriceps EMG and hamstring coactivation EMG than the multi-radius group. Single-radius demonstrated more abduction angular displacement and reached peak abduction earlier than the multi-radius arthroplasty limb. The single- radius the percent body fat showed similar values in the Elderly, Single and Multi-radius group among the periods, however Control group was Lowered among the periods. Single-radius group limb also increased the quadriceps muscle activation level to produce more knee extension moment to compensate for the short quadriceps moment arm. Resting metabolic rate was significantly increased in control group in the period of LI. Energy expenditure was extremely increased in all groups except control group among the periods. We can say this is the exercise effects.