• Journal of Biomedical Engineering Research
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• v.37 no.2
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• pp.68-74
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• 2016

In this study, we investigated the rotational characteristics which were comprised of directionality and linearity of target registration error (TRE) as a study in advance to enhance the accuracy of contour-based registration in neuronavigation. For the experiment, two rigid head phantoms that have different faces with specially designed target frame fixed inside of the phantoms were used. Three-dimensional coordinates of facial surface point cloud and target point of the phantoms were acquired using computed tomography (CT) and 3D scanner. Iterative closest point (ICP) method was used for registration of two different point cloud and the directionality and linearity of TRE in overall head were calculated by using 3D position of targets after registration. As a result, it was represented that TRE had consistent direction in overall head region and was increased in linear fashion as distance from facial surface, but did not show high linearity. These results indicated that it is possible for decrease TRE by controlling orientation of facial surface point cloud acquired from scanner, and the prediction of TRE from surface registration error can decrease the registration accuracy in lesion. In the further studies, we have to develop the contour-based registration method for improvement of accuracy by considering rotational characteristics of TRE.

• Journal of Biomedical Engineering Research
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• v.41 no.5
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• pp.195-202
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• 2020

Needle detection in ultrasound images is sometimes difficult due to obstruction of fat tissues. Accurate needle detection using continuous ultrasound (CUS) images is a vital stage of treatment planning for tissue biopsy and brachytherapy. The main goal of the study is classified into two categories. First, new detection model, i.e. D-Attention Unet, is developed by combining the context information of 3D medical data and CUS images. Second, the D-Attention Unet model was compared with other models to verify its usefulness for needle detection in continuous ultrasound images. The continuous needle images taken with ultrasonic waves were converted into still images for dataset to evaluate the performance of the D-Attention Unet. The dataset was used for training and testing. Based on the results, the proposed D-Attention Unet model showed the better performance than other 3 models (Unet, D-Unet and Attention Unet), with Dice Similarity Coefficient (DSC), Recall and Precision at 71.9%, 70.6% and 73.7%, respectively. In conclusion, the D-Attention Unet model provides accurate needle detection for US-guided biopsy or brachytherapy, facilitating the clinical workflow. Especially, this kind of research is enthusiastically being performed on how to add image processing techniques to learning techniques. Thus, the proposed method is applied in this manner, it will be more effective technique than before.

• Journal of Veterinary Clinics
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• v.37 no.2
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• pp.100-105
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• 2020

A 9-month-old, 11.3 kg, intact, male, mixed-breed dog was referred for treatment of cor triatriatum dexter (CTD); a 5-month-old, 1.9 kg, intact, male Maltese for pulmonic stenosis (PS); and a 3-year-old, 6.62 kg, intact, female West Highland white terrier for esophageal stricture with regurgitation. A balloon catheter intervention was performed in the dog with CTD, and subsequent color Doppler ultrasound and abdominal ultrasound showed normal blood flow across the perforated membrane dividing the right atrium and the disappearance of the severe ascites present before treatment. Balloon catheter intervention in the dog with PS reduced the blood flow through the stenosis from 5.82 m/s to 3.97 m/s. In the dog with esophageal stricture, balloon catheter intervention widened the esophagus and no subsequent regurgitation was observed. Balloon catheter intervention is an interventional radiology procedure that represents a definitive treatment option for various stenotic lesions in dogs, including CTD, PS, and esophageal stricture. Although interventional radiology procedures for these diseases have already been reported, details of procedures and successful outcome have not been reported in Korea.

• Journal of Chest Surgery
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• v.53 no.2
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• pp.41-48
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• 2020

Background: Chylothorax after congenital heart surgery is not an uncommon complication, and it is associated with significant morbidity. However, consensus treatment guidelines are lacking. To improve the treatment outcomes of patients with postoperative chylothorax, we implemented a standardized management protocol at Severance Hospital in September 2014. Methods: A retrospective review of patients treated at a single center was done. All corrective and palliative operations for congenital heart disease performed at our institution between January 2008 and April 2018 were reviewed. The incidence and treatment outcomes of postoperative chylothorax were analyzed. Results: The incidence of chylothorax was 1.9%. Sixty-one percent of the patients could be managed with a low-fat diet, while 28% of the patients required complete restriction of enteral feeding. Thoracic duct embolization was performed in 2 patients and chest tube drainage decreased immediately after the procedure. No patient required thoracic duct ligation or pleurodesis. After implementation of the institutional management protocol, the number of chest tube drainage days decreased (median, 24 vs. 14 days; p=0.45). Conclusion: Implementing a strategy to reduce postoperative chylothorax resulted in an acceptable incidence of postoperative chylothorax. Instituting a clinical practice protocol helped to curtail the treatment duration and to decrease the requirement for surgical treatment. Image-guided embolization of the thoracic duct is an effective treatment for postoperative chylothorax.

• The Journal of the Korean dental association
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• v.55 no.11
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• pp.778-788
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• 2017

Ultrasound sonography(US) is used to evaluate various diseases of oral and maxillofacial region including salivary glands, soft tissue and jaw lesions because of easy accessibility and no hazard of ionizing radiation. Also, US can offer dynamic study showing real-time images during diagnostic or surgical procedure. US images provide accurate information about the internal features of lesions on the jaw prior to surgical treatment. Doppler images are used to visualize the vascular distribution of the lesions and to provide additional information to enhance diagnostic value. It is necessary to evaluate the diagnostic value of US and evaluate its usefulness by looking at clinical cases using US images. Therefore, US imaging may be recommended as an assistant image in evaluating jaw lesions. US images provided accurate information about the internal structure of lesions on the jaw prior to surgical treatment, and diagnostic value was enhanced by visualizing the vascular distribution of the lesion using doppler imaging. We report the protocol and suggest the effectiveness of US for various lesions and US-guided sialography.

• The Journal of the Korean dental association
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• v.55 no.11
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• pp.789-799
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• 2017

Ultrasound images are noninvasive, can be observed in real time, have no radiation exposure, do not cause pain, and are not restricted in use depending on the patient's prosthetic implant or medical condition. Since the use of ultrasound in the dental field was first applied for tooth preparation in 1957, the use of diagnostic ultrasound for the first time in 1963 has been reported. Currently, it is used in the diagnosis of soft tissue lesions such as malignant tumor or salivary gland disease, fine needle aspiration test, temporomandibular joint disease, lymph node metastasis, measurement of muscle thickness and inflammatory diseases, differentiation of periapical cyst and granulation tissue, measurement of periodontal tissue thickness. The ultrasound image can be visualized in real time. The clinician can explain the structure to the patient while consulting the patient and consult the patient. When injecting the drug into a specific site or aspirating a specific site or substance, So that it can be confirmed and practiced. Recently, ultrasonic equipment specialized in the dental field has been developed and marketed, and it is expected that the use of ultrasonic waves will become active in the dentistry. In the future, development of popular equipment with size and frequency suitable for dental diagnosis and various researches on maxillofacial ultrasonic anatomy. If clinical studies are continuously carried out to demonstrate efficacy, ultrasound is expected to aid in accurate diagnosis and treatment throughout the dentistry.

• Progress in Medical Physics
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• v.15 no.4
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• pp.197-201
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• 2004

Stereotactic brain biopsy using stereotactic head frame such as CRW (Radionics, USA) has demonstrated a precise lesion localizing accuracy. In this study, we developed the target point calculation program for brain lesion biopsy using CRW stereotactic head frame and designed a phantom for verify the new developed program. The phantom was designed to have capability to simulate clinical stereotactic brain biopsy. The phantom has 10 vertical rods whose diameters are 6mm and tip of each rods are 2mm. Each rod has different length, 150 mm x 4 ea, 130 mm x 4 ea, 110 mm x 2 ea. CT images were acquired with Simens CT scanner as continuous transverse slice, 1 mm thickness in a 25 cm field of view and stored in a dicom file as a 256 x 256 matrix. As a result, the developed new target localization program will be useful for planning and training in complicated 3 dimensional stereotactic brain biopsy.

• Progress in Medical Physics
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• v.7 no.1
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• pp.37-52
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• 1996

Image-guided localized, water-suppressed in vivo $^1$H MR spectroscopic studies were performed on the patients with brain tumors, acute cerebral infarction and schizophrenia, and dogs. GE Signa 1.5 T whole-body MRI/MRS system using STEAM pulse sequence was used. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. In vivo $^1$H MR spectra in brain neoplastic tissues revealed the changes of signal intensities of N-acetylaspartate (NAA), choline (Cho) and lactate (Lac) resonances. The present results suggest that the observed metabolite alterations from localized, water-suppressed in vivo $^1$H MR spectroscopy can be useful as an index of brain tumors, cerebral infarction and schizophrenia, and provide good quality metabolic information of cerebral tissue in the field of thanato-chronology.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.266-274
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• 2009

An abdominal aortic aneurysm occurs most commonly in older individuals (between 65 and 75), and more in men and smokers. The most important complication of an abdominal aortic aneurysm is rupture, which is most often a fatal event. An abdominal aortic aneurysm weakens the walls of the blood vessel, leaving it vulnerable to bursting open, or rupturing, and spilling large amounts of blood into the abdominal cavity. surface modeling is very useful to surgery for quantitative analysis of abdominal aortic aneurysm. the 3D representation and surface modeling an abdominal aortic aneurysm structure taken from Multi Detector Computed Tomography. The construction of the 3D model is generally carried out by staking the contours obtained from 2D segmentation of each CT slice, so the quality of the 3D model strongly defends on the precision of segmentation process. In this work we present deformable model algorithm. deformable model is an energy-minimizing spline guided by external constraint force. External force which we call Gradient Vector Flow, is computed as a diffusion of a gradient vectors of gray level or binary edge map derived from the image. Finally, we have used snakes successfully for abdominal aortic aneurysm segmentation the performance of snake was visually and quantitatively validated by experts.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.535-543
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• 2021

The purpose of this study is to investigate various opinions on changes and revisions in the Medical Technician Act, to compare the curriculum of radiological technologist and physicians or dentists, and to compare the definitions and scope of work of radiological technologist in Korea and abroad. From the information, The goal is to review whether the phrase 'guidance of a doctor or dentist' specified in the definition of the 'Act on Medical Technicians, etc.' is realistically appropriate. radiological technologist receive specialized college education on radioligical science & medical imaging. The training hours for radiolgical science student are greater than medical students. In addition, radiological technologists are continuously developing their competencies for new knowledge and skills through continuing education in clinical fields. In particular, radiological technologist are making steady research efforts to reduce patient exposure and improve medical image quality. As a result of this investigation, it is considered that the term "guided by a doctor or dentist" as currently defined in the 'Act on Medical Technicians, etc.' may need to be revised in consideration of the professionalism of the radiological technologist.