• Progress in Medical Physics
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• v.13 no.4
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• pp.234-241
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• 2002

The depth electrode technique, especially using the occipito-temporal route is widely used in the clinic, since it is known to be the most precise method about the invasive study of the mesial temporal lobe epilepsy. The depth electrode with the occipito-temporal route has been applied with manual calculation of MR images. Inherently there are some factor causing significant errors due to geometrical axis alignment, such as miss alignment of horizontal or vertical cutting line. In order to correct it in manually, it takes a long time. In this study, authors has developed the software for automate calculation of MRI wording for instance calculation and for the no time delaying operation. Authors could show that this software is useful for the clinic after applying if for 33 cases of the patients.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.468-474
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• 2019

Deep brain stimulation (DBS) is an effective surgical procedure for treating drug refractory movement disorders, and DBS involves delivering high frequency electrical stimulation to deep brain nuclei. Microelectrode recording (MER) is a complementary test that can precisely identify the location of deep brain nuclei, along with MRI correlation, during DBS surgery to improve the surgical outcome and minimize side effects. The purpose of this paper is to analyze the neuro-physiological waveforms and identify the usefulness of MER by analyzing the MER performed during DBS surgery for treating movement disorders. We retrospectively reviewed 28 patients who underwent MER during DBS surgery for movement disorders from January to December 2018. Of the 28 patients, 38 MERs for the subthalamic nucleus (STN), 10 MERs for the globuspallidusinternus (Gpi), and 4 MERs for the ventral intermediate thalamic nucleus (VIM) were performed. In all the cases, the target sites were found and micro-stimulations were used to check for side effects and to readjust the target sites. The clinical symptoms of all 28 patients improved after surgery. In conclusion, MER is a useful test that employs neuro-physiological waveforms to accurately identify the deep brain nuclei, along with MRI correlation, to improve the DBS surgical outcomes for movement disorders and to minimize side effects.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.313-320
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• 1989

In capacitive heating device, which considered efficient for deep heating, parallel arrangement of the electrodes is a serious limiting factor in heating for eccentrically located lesions because it causes overheating of the exposed ipsilateral skin surface, the heating pattern is also frequently inappropriate, and the arrangement tends to be unstable due to the patient's gravity. Therefore we attempted an angular arrangement of the electordes to achieve more homogenous and efficient heating for such lesions. In phantom study, both the thermal profile and thermogram established the heating pattern in this unusual angular arrangement of the electrodes at $60^{\circ},\;90^{\circ}\; and\;120^{\circ}$ angles, respectively. An angular arrangement was also clinically applied to 3 patients. The patients' tolerance was good without significant complication and the thermal distribution was satisfactory. In conclusion, this unusual arrangement of electrodes appears to be promising in the clinical application to the eccentrically located lesions.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.422-427
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• 1999

Background: Tachycardia induced heart failure model would be the model of choice for the dilated cardiomyopathy. This more closely resembles the clinical syndrome and does not require major surgical trauma, myocardial ischemia and pharmacological or toxic depression of cardiac function. When heart failure is progressive, application of new surgical procedures to the faling heart is highly risky. It has been shown that recovery trajectory from heart failure is a new method in decreasing animal mortality. The purpose is to establish the control datas for recovery trajectory in the canine heart failure model. Material and Method: 21 mongrel dogs were studied at 4 stages(baseline, at the heart failure, 4 and 8 weeks after recovery). Heart failure was induced during 4 weeks of continuous rapid pacing using a pacemaker. Eight weeks of trajectory of recovery period was allowed. Indices of left ventricular function and dimension were measured every 2 weeks and the hemodynamics were measured by use of Swan-Ganz catheterization and thermodilution method every 4 weeks. Values were expressed as mean${\pm}$standard deviation. Result: 4(20%) dogs died due to heart failure. Left ventricular end-diastolic volume at the 4 stages were 40.8${\pm}$7.4, 82.1${\pm}$21.1, 59.9${\pm}$7.7 and 46.5${\pm}$6.5ml. Left ventricular end-systolic volume showed the same trend. Ejection fractions were 50.6${\pm}$4.1, 17.5${\pm}$5.8, 36.3${\pm}$7.3, and 41.5${\pm}$2.4%. Blood pressure and heart rate showed no significant changes. Pressures of central vein, right ventricle, pulmonary artery, and pulmonary capillary wedge showed significant increase during the heart failure period, normalizing at the end of recovery period. Stroke volumes were 21.5${\pm}$8.2, 12.3${\pm}$3.5, 17.9${\pm}$4.6, and 15.5${\pm}$3.4ml. Blood norepinephrine level was 133.3${\pm}$60.0pg/dL at the baseline and 479.4${\pm}$327.3pg/dL at the heart failure stage(p=0.008). Conclusion: Development of tachycardia induced heart failure model is of high priority due to ready availability and reasonable amenability to measurements. Recovery trajectory after cessation of tachycardia showed reduction of cardiac dilatation and heart function. Application of new surgical procedures during the recovery period could decrease animal mortality.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.393-397
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• 1998

A 25-year-old man with viral cardiomyopathy and chronic active hepatitis successfully underwent dynamic cardiomyoplasty for the first time in Korea on July 30, 1996. The patient had been intermittently dyspneic for 5 years and was admitted to our center twice because of heart failure. For the past 2 years, he was NYHA functional class III status with a left ventricular ejection fraction(LVEF) of around 30%. The patient was born with scoliosis and showed a short stature. The liver function showed elevated liver enzymes, and hepatitis B antigen was positive. The liver biopsy revealed chronic active hepatitis. The preoperative echocardiogram showed decreased left ventricular function with grade II mitral and grade II tricuspid regurgitation with dilated left and right atrium. Recently his symptoms worsened and we decided to perform a dynamic cardiomyoplasty. The left latissmus dorsi muscle(LDM) was mobilized and tested with lead placement on his right lateral decubitus position. The patient was positioned into supine and, after median sternotomy, the heart was wrapped with the mobilized muscle. The Russian made cardiomyostimulator(EKS-445) and leads (Myocardial PEMB for heart and PEMP-1 for LDM) were used. The total operation time was 8 hours and there were no perioperative episodes. Postoperatively the LDM had been trained for a 10 week period and currently the stimulation ratio is maintained at 1:4. The postoperative LVEF did not increase with the value of 30-35%. However, the patient feels better postoperatively with slightly increased activity.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.155-164
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• 2003

The validity and efficiency of the roll-along technique widely used in 2-D electrical resistivity survey are analyzed in case of the dipole-dipole and the Wenner-Schlumberger arrays by numerical modelling. The shallow anomalous resistivity bodies are successfully inverted both in the dipole-dipole and in the Wenner-Schlumberger arrays because the shallow data of pseudosection are not omitted by the roll-along technique. However, the deep anomalous resistivity bodies can not be well resolved due to the skip of observed data which is more significant in the Wenner-Schlumberger array having relatively poor horizontal coverage of obtaining data. Carrying out electrical survey adopting the dipole-dipole array, the skip of data is insignificant because it is unfeasible to expand the electrodes to the maximum electrode separation coefficient($n_max$) owing to low S/N ratio. In case of the Wenner-Schlumberger array, however, because it is generally feasible to expand the electrodes $n_max$ to the owing to high S/N ratio, it is highly possible that skip of data from the roll-along technique causes significant distortion of inversion results. Therefore, adopting the Wenner-Schlumberger array having deeper median depth(Edwards, 1977) than do the dipole-dipole array on condition of the same unit electrode spacing( ($a$) ) and $n_max$, it is recommended to determine $a$ based on not $n_max$but $n_prob$free from the skip of observing data and forward electrodes with keeping overlap interval 3/4 of the survey line length in order to reduce the distortion of resistivity structure and perform resistivity survey efficiently. These results are confirmed by numerical modelling.

• Journal of Advanced Engineering and Technology
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• v.11 no.4
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• pp.267-271
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• 2018

A high-frequency therapy device with improved output by modifying a high-frequency stimulator was fabricated. The details of the design include generating part design, high-frequency transformer design, large output FET installation, DC voltage input part design and gate input driver design. Based on the real test using the pork meat, the temperature distributions according to the current electric transfer method, penetration depth, electrode diameter size were measured. In the CET method, the penetration depth was 0.5 cm and in the RET method, the penetration depth was 20 cm or more. In addition, it was confirmed that the temperature rise according to the penetration depth in the RET system was substantially constant, and the temperature rise was remarkable as the electrode diameter was small. As a result, it has been confirmed that the high frequency therapy device is highly affected by various conditions of the electrode.

• The Journal of Korean Physical Therapy
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• v.11 no.3
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• pp.81-87
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• 1999

The purpose of this study was to determine the effect of electrical stimulation on the number of MCs and percent of degranulated MCs in rat skin. Twelve male Sprague-Dawley rats were divided into two group; electrical stimulation group (n=6) and control group (n=6). Each animals hair on the back was removed. The electrical stimulation group received an positive rectangular pulsed electrical stimulation, while the control group was given the same treatment without electricity. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with toluidine blue-nuclear fast red and alcian blue-safranin O. respectively. The MCs were counted using a light microscope and computerized image analysis system and calculated as the density and the percent. A t-test showed a significantly higher density of MCs in the electrical stimulated rats than control rats(p<0.05), and the percent of degranulated MCs in the electrical stimulated rats was higher than in the control rats (p<0.05) in toluidine blue stained sections. The density of MCs was significantly higher in the electrical stimulated rats than the control rats in alcian blue-safranin O Stained sections (P<0.01). An analysis of variance showed that the densities of CTMCs was significantly lower than the densities of MMCs and mixed MCs in electrical stimulated rat in alcian blue-safranin O Stained sections (p<0.05). These results suggest that the electrical stimulation may have potential for increasing the number of MCs and lead to degranulate the MCs in rat skin.

• The Korean Society of Law and Medicine
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• v.24 no.2
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• pp.147-196
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• 2023

Advances in brain science have made it possible to stimulate the brain to treat brain disorder or to connect directly between the neuron activity and an external devices. Non-invasive neurotechnologies already exist, but invasive neurotechnologies can provide more precise stimulation or measure brainwaves more precisely. Nowadays deep brain stimulation (DBS) is recognized as an accepted treatment for Parkinson's disease and essential tremor. In addition DBS has shown a certain positive effect in patients with Alzheimer's disease and depression. Brain-computer interfaces (BCI) are in the clinical stage but help patients in vegetative state can communicate or support rehabilitation for nerve-damaged people. The issue is that the people who need these invasive neurotechnologies are those whose capacity to consent is impaired or who are unable to communicate due to disease or nerve damage, while DBS and BCI operations are highly invasive and require informed consent of patients. Especially in areas where neurotechnology is still in clinical trials, the risks are greater and the benefits are uncertain, so more explanation should be provided to let patients make an informed decision. If the patient is under guardianship, the guardian is able to substitute for the patient's consent, if necessary with the authorization of court. If the patient is not under guardianship and the patient's capacity to consent is impaired or he is unable to express the consent, korean healthcare institution tend to rely on the patient's near relative guardian(de facto guardian) to give consent. But the concept of a de facto guardian is not provided by our civil law system. In the long run, it would be more appropriate to provide that a patient's spouse or next of kin may be authorized to give consent for the patient, if he or she is neither under guardianship nor appointed enduring power of attorney. If the patient was not properly informed of the risks involved in the neurosurgery, he or she may be entitled to compensation of intangible damages. If there is a causal relation between the malpractice and the side effects, the patient may also be able to recover damages for those side effects. In addition, both BCI and DBS involve the implantation of electrodes or microchips in the brain, which are controlled by an external devices. Since implantable medical devices are subject to product liability laws, the patient may be able to sue the manufacturer for damages if the defect caused the adverse effects. Recently, Korea's medical device regulation mandated liability insurance system for implantable medical devices to strengthen consumer protection.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.52-59
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• 2008

We have developed a new deep-towed marine DC resistivity survey system. It was designed to detect the top boundary of the methane hydrate zone, which is not imaged well by seismic reflection surveys. Our system, with a transmitter and a 160-m-long tail with eight source electrodes and a receiver dipole, is towed from a research vessel near the seafloor. Numerical calculations show that our marine DC resistivity survey system can effectively image the top surface of the methane hydrate layer. A survey was carried out off Joetsu, in the Japan Sea, where outcrops of methane hydrate are observed. We successfully obtained DC resistivity data along a profile ${\sim}3.5\;km$ long, and detected relatively high apparent resistivity values. Particularly in areas with methane hydrate exposure, anomalously high apparent resistivity was observed, and we interpret these high apparent resistivities to be due to the methane hydrate zone below the seafloor. Marine DC resistivity surveys will be a new tool to image sub-seafloor structures within methane hydrate zones.