• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.173-181
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• 2015

We developed a wireless gamma-ray probe based on radiation photon counting method to diagnose and detect remaining lesions after surgery, and its effectiveness was evaluated using calibration sources and a phantom. The probe was designed and miniaturized using a semi-conductor-based radiation sensor, and a Bluetooth remote communication module was used to implement the wireless diagnosis and detection system. Moreover, a remote monitoring system was implemented to monitor affected areas during diagnosis and surgery. To assess the effectiveness of the developed probe in this study, calibration sources $^{57}Co$, $^{133}Ba$, $^{22}Na$ and $^{137}Cs$ and a chicken breast phantom were used. Furthermore, the probe's detection response to gamma ray was confirmed through evaluation. Its clinical applicability was verified by assessing the response linearity and detection direction according to gamma-ray intensity, as well as the detection efficiency according to the depth of the gamma source in the phantom.

• Radiation Oncology Journal
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• v.5 no.2
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• pp.173-176
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• 1987

Carcinoma of extrahepatic biliary tract is slow growing tumor but curative resection is rarely successful. Radiation therapy has been introduced for enhancing palliation and possible longterm survival. We treated a case of advanced extrahepatic biliary tract carcinoma with high dose rate remote afterloading system through T-tube as a initial irradiation postoperatively. We hope that this treatment may affect not only ennancing palliation and better quality of life but also in local tumor control.

• Journal of Chest Surgery
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• v.55 no.2
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• pp.108-117
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• 2022

Background: The efficacy of telemedicine among cancer survivors is uncertain. The Smart After-Care Program (SAP), which is an interactive, smartphone-based remote health monitoring system, was developed to help patients manage their health after leaving the hospital. This study was designed to evaluate the efficacy of our remote health care program for lung cancer patients. Methods: We enrolled 50 patients with lung cancer. Self-monitoring devices were supplied to all patients, who were instructed to enter their daily vital signs and subjective symptoms to the Smart After-Care app. The app also provided information about rehabilitation exercises and a healthy diet for lung cancer patients. All patients received health counseling via telephone once a week and visited an outpatient clinic during weeks 6 and 12 to assess satisfaction with the SAP and changes in quality of life and physical performance. Results: Overall satisfaction with the SAP was very high (very good, 61.9%; good, 26.2%). In the multivariate analysis to identify factors affecting satisfaction, the distance between the patient's residence and the hospital was the only significant independent factor (p=0.013). Quality of life improved along all functional scales (p<0.05). Muscle strength significantly improved in the lower limbs (p=0.012). Two-minute walk distance also significantly improved (p=0.028). Conclusion: This study demonstrated that the SAP was acceptable for and supportive of patients with reduced pulmonary function after lung cancer treatment. The SAP was found to be particularly useful for patients living far from the hospital.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.360-364
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• 2009

Objective : Several treatment options have proven effective for metastatic brain tumors, including surgery and stereotactic radiosurgery. Tumors with cystic components, however, are difficult to treat using a single method. We retrospectively assessed the outcome and efficacy of gamma knife radiosurgery (GKRS) for cystic brain metastases after stereotactic aspiration of cystic components to decrease the tumor volume. Methods : The study population consisted of 24 patients (13 males, 11 females; mean age, 58.3 years) with cystic metastatic brain tumors treated from January 2002 to August 2008. Non-small cell lung cancer was the most common primary origin. After Leksell stereotactic frame was positioned on each patient, magnetic resonance images (MRI)-guided stereotactic cyst aspiration and GKRS were performed (mean prescription dose : 20.2 Gy). After treatment, patients were evaluated by MRI every 3 or 4 months. Results : After treatment, 13 patients (54.2%) demonstrated tumor control, 5 patients (20.8%) showed local tumor progression, and 6 patients (25.0%) showed remote progression. Mean follow-up duration was 13.1 months. During this period, 10 patients (41.7%) died, but only 1 patient (4.2%) died from brain metastases. The overall median survival after these procedures was 17.8 months. Conclusion : These results support the usefulness of GKRS after stereotactic cyst aspiration in patients with large cystic brain metastases. This method is especially effective for the patients whose general condition is very poor for general anesthesia and those with metastatic brain tumors located in eloquent areas.

• Journal of Chest Surgery
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• v.45 no.1
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• pp.24-29
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• 2012

Background: The conventional method of aortic cross-clamping is very difficult and increases the risk of cerebral infarct due to embolism of the calcified aorta in these patients. Accordingly, we analyzed our experience with 11 cases of ascending aorta and aortic valve replacement with hypothermic circulatory arrest. Materials and Methods: From January 2002 to December 2009, 11 patients had ascending aorta and aortic valve replacement with hypothermic arrest at our hospital. We performed a retrospective study. Results: There were 5 males and 6 females, with a mean age of 68 years (range, 44 to 82 years). Eight patients had aortic stenosis, and 3 patients had aortic regurgitation. An aortic cannula was inserted into the right axillary artery in 3 patients and ascending aorta in 6 patients. Two patients with aortic regurgitation had a remote access perfusion catheter inserted though the right femoral artery. The mean cardiopulmonary bypass time was 180 minutes (range, 110 to 306 minutes) and mean hypothermic circulatory arrest time was 30 minutes (range, 20 to 48 minutes). The mean rectal temperature during hypothermic circulatory arrest was $21^{\circ}C$ (range, $19^{\circ}C$ to $23^{\circ}C$). No patient had any new onset of cerebral infarct or cardiovascular accident after surgery. There was no hospital mortality. Early complications occurred in 1 patient who needed reoperation due to postoperative bleeding. Late complications occurred in 1 patient who underwent a Bentall operation due to prosthetic valve endocarditis. The mean follow-up duration was 32 months (range, 1 month to 8 years) and 1 patient died suddenly due to unknown causes after 5 years. Conclusion: Patients with a calcified aorta can be safely treated with a technique based on aorta and aortic valve replacement under hypothermic circulatory arrest.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.105-112
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• 2020

The increase in the edentulous jaw which occurs in the aged population has led to personal dental health concerns. In the case of dental implant surgery, the duration of a patient's recovery depends on the surgical plan and their physicical ability. A device may be required to assist a physician in controlling vibration reduction of free-hand drilling and prescribing a good treatment plan that is suitable for the patient's condition. In this work, an artificial tooth-root implant assistant manipulator was studied. The structure and the vibration analysis of the dynamic restraint manipulator that is for drilling the alveolar bone in the mandible bone were performed, and the structural stability was analyzed. Further, a virtual prototype of an artificial tooth-root implant assisted manipulator was fabricated and tested. Hence, the state of the Remote Center of Motion (RCM) point and the driving state of the manipulator were confirmed. Furthermore, the drilling experiments were performed by using materials similar to a human jawbone in order to evaluate the performance of the drilling process that is operated using the assistant manipulator.

• Journal of Chest Surgery
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• v.26 no.1
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• pp.32-35
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• 1993

During the period from September 1989 through December 1992, 118 cases of coronary arterial bypass graft were performed at Department of Cardiothoracic Surgery, Asan Medical Center. Twenty-one of these had history of recent or remote percutaneous transluminal coronary angioplasty. They consisted of 13 males[age,58.7 + 5.4 years] and 8 females[age, 63.6 + 2.8years] with the mean age of 60.6. History of old myocardial infarction was noted in 24%[5/21] of the patients and congestive heart failure in 2 cases. The angina by type of presentation is unstable in all of the patients. The patterns of involvement of coronary arterial disease were left main disease[1], single vessel disease[5], double vessel involvement[10], and triple vessel involvement[5]. We performed 4 cases of single bypasses, 7 cases of double, 8 cases of triple, and 2 cases of quadruple bypasses. Total of 51 grafts[LIMA:12, RSVG:39] were inserted in 21 cases with average of 2.4 grafts per patient. The methods of myocardial protection were cold blood cardioplegia[8 cases], intermittent aortic occlusion[11], and continuous coronary perfusion with local coronary sharing[2]. There were no operative or late death. The only cardiac complication was 1 case of low cardiac output required IABP. The other complications were 1 case of sternal wound infection and 1 case of postoperative bleeding required reoperation. And there was no case of perioperative myocardial infarction. Postoperatively, 3 cases of recurrent angina were detected at 5, 7, and 18months after surgery. One of them was managed successfully with repeat PTCA[who was recurred 18 months postoperatively], and the other two with medication. I conclude that we can approach the patients more aggressively with PTCA, because of our acceptable operative risks.

• Archives of Reconstructive Microsurgery
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• v.8 no.2
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• pp.130-138
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• 1999

The lower extremity injuries are extremely increasing with the development of industrial & transportational technology. For the lower extremity injuries that result from high-energy forces, particularly those in which soft tissue and large segments of bone have been destroyed and there is some degree of vascular compromise, the problems in reconstruction are major and more complex. In such cases local muscle coverage is probably unsuccessful, because adjacent muscles are destroyed much more than one can initially expect. Reconstruction of the lower extremity has been planned by dividing the lower leg into three parts traditionally The flaps available in each of the three parts are gastrocnemius flap for proximal one third, soleus flap for middle one third and free flap transfer for lower one third. Microvascular surgery can provide the necessary soft tissue coverage from the remote donnor area by free flap transfer into the defect. Correct selection of the appropriate recipient vessels is difficult and remains the most important factor in successful free flap transfer. Vascular anastomosis to recipient vessels distal to the zone of injury has been advocated and retrograde flow flaps are well established in island flaps. Retrograde flow anastomosis could not interrupt the major blood vessels which were essential for survival of the distal limb, the compromise of fracture or wound healing might be prevented. During 5 years, from March 1993 to Feb. 1998, we have done 68 free flap transfers in 61 patients to reconstruct the lower extremity. From analysis of the cases, we concluded that for the reconstruction of the lower extremity, free flap transfer yields a more esthetic and functional results.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.641-646
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• 1997

Understanding of the surgical anatomy of patients with double outlet right ventricle (DORV) is important in the planning of biventricular repair From May 1995 to September 1996, 7 patients underwent biventricular repair for DORV with remote ventricular septal defect. There were 5 males and 2 (tamales. Age at operation varied from 2 to 9 years(mean 3.4$\pm$ 2.7years). Preoperative diagnostic assessment was made by two-dimensional echocardiography and cardiac catheterization. Ventricular septal defect was perimembranous inlet type in all patients. Associated cardiac anomalies were pulmonary atresia in two, pulmonary stenosis in five and tricuspid chordal attachment to zonal septum in five. The operations were performed intraventricular repair and pulmonary enlargement in two, REV operation in two, and Rastelli operation in three. There was no early postoperative deaths and complications. The follow-up period war from 1 month to 18mon1hs, averaging 10: 6.1 months. In the past, we considered the Fontal operation indicative as primary choice when DORV was associated with abnormal tricuspid chordal attachment to the zonal septum, but now we believe that biventricular repair is feasible for those cases by making conal flap or reattachment method. Biventricular repair has theoretic advantages because it estabilishes normal anatomy and physiology, and it was concluded that the precise preoperative evaluation using both echocardiography and cardiac catheterization was essential to the successful surgery.

• Biomedical Science Letters
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• v.11 no.3
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• pp.307-310
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• 2005

Cerebral ischemia results in neuronal changes in remote areas that have fiber connections with the ischemic area. The aim of this study was to investigate the nigral changes by examining the correlation between the apparent diffusion coefficient (ADC) and the tissue structure. Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Four days after the occlusion, when T2-weighted images revealed the presence of an area of high signal intensity in the ipsilateral substantia nigra, and the ADCs were calculated and imaged. Histopathologic examination by both light and electron microscopy was performed on day 4 after surgery. This finding was consistent with the high signal intensity seen on T2-weighted and diffusion-weighted images, as well as with the ADC reduction, but we did not expect to observe uniform ADC reduction attributable mainly to astrocytic swelling in the perivascular end-feet.