• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.31-37
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• 2007

The purpose of this research was to compare and analyze image quality for each Detector of CR(Computed Radiography) and DR(Digital Radiography). The results showed that CR(AGFA MD 4.0 General plate, JAPAN) was superior to DR(HOLOGIC nDirect Ray, USA) based on the quantitative values and comparison of MTF(Modulation Transfer Function), NPS(Noise Power Spectrum), Photon fluence and DQE(Detective Quantum Efficiency) which have been widely accepted for the estimation of CR and DR. Quantitative evaluations of CR and DR system were obtained and they may be very helpful for QA and QC of general X-ray systems.

• Journal of radiological science and technology
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• v.45 no.4
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• pp.305-312
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• 2022

The proportion and testing of portable radiation tests, which are limited at the request of the doctor, are gradually increasing only for patients in emergency situations and difficulties in moving. However, as there are many limiting factors compared to fixed devices, this study intends to measure and analyze the distortion of images according to the angle of the detector and the change in dose according to the position of the subject. For distortion experiments using a mobile radiation generator used in Hospital A, the SID was tilted by 110 cm, 14"×17" wireless FPD detector to 0°, -5°, -10°, -15°, -20°, and -35° to measure the change in area. The dose according to the location of the detector was analyzed on average by measuring the central dose at 110 cm of the SID and measuring the dose of 9 locations three times each. The analysis result of distortion by location according to the angle of the detector showed a statistically significant difference (f=58.74, p<0.000). Therefore, it can be seen that the angle of the detector and the tube is closely related to the distortion of the image. The difference in dose by location of the detector increased with respect to the center - pole, and decreased with the + pole. Tests using mobile radiation generators will require careful efforts by clinicians to position patients in the center of the detector for accurate diagnosis, and efforts will be made to level the angle between the mobile radiation generators and the detector.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.519-526
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• 2023

This study was intended to evaluate the shielding rate of radiation shields manufactured using 3D printers that have recently been used in various fields by comparing them with existing shields made of lead, and to find out their applicability through experiments. A 3D printer shield made of tungsten filament 1 mm, 2 mm, 4 mm shield, RNS-TX (nanotungsten) 1.1 mm, lead 0.2 mmPb, and 1mmPb were exposed to ^99mTc, ¹⁸F, and ²⁰¹TI for 15, 30, 45 minutes, and 60 minutes after measuring cumulative dose three times. Based on this, the shielding rate of each shield was calculated based on the dose in the absence of the shield. In addition, ^99mTc, ¹⁸F, and ²⁰¹TI were located 100 cm away from the phantom in which the OSLD nano Dot device was inserted, and if there was no shield for 60 minutes, the dose of thyroid was measured using 1.0 mm of lead shield, 1.1 mm of RNS-TX shield, and 2 mm of tungsten shield made by 3D printer. The use of shields during radiation shielding emitted from open radiation sources all resulted in a reduction in dose. The radiation dose emitted from the radionuclides under the experiment was all reduced when the shield was used. This study has been confirmed that tungsten is a material that can replace lead due to its excellent performance and efficiency as shield, and that it even shows the possibility of manufacturing a customized shield using 3D printer.

• Investigative Magnetic Resonance Imaging
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• v.19 no.3
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• pp.191-195
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• 2015

We present a 53-year-old woman with a large chest wall mass in the interpectoral space, which was eventually confirmed as a lipogranuloma resulting from hydrogel implant rupture. Ultrasonography (US) showed reduced implant volume with surrounding peri-implant fluid collection, suggesting the possibility of implant rupture. A heterogeneously hypoechoic mass was found between the pectoralis major and minor muscles adjacent to the ruptured implant. On magnetic resonance imaging (MRI), there was a large mass in the left interpectoral space of the upper inner chest wall. The mass showed slightly high signal intensity (SI) on pre-contrast T1-weighted image (WI) with mixed iso and high SI on T2-WI. The signal of the mass was suppressed using the water suppression technique but not with the fat suppression technique on T2-WI. The mass showed diffuse enhancement upon contrast enhancement. The enhancing kinetics showed persistent enhancement pattern. US-guided core needle biopsy revealed a lipogranuloma and removal confirmed a ruptured PIP hydrogel implant.

• Imaging Science in Dentistry
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• v.43 no.1
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• pp.31-36
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• 2013

Purpose: This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was $1.01{\pm}0.66$ mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined. Results: All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates. Conclusion: The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

• Imaging Science in Dentistry
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• v.49 no.2
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• pp.79-86
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• 2019

Purpose: This study reviewed the common conditions associated with displacement of inferior alveolar nerve canal. Materials and Methods: General search engines and specialized databases including Google Scholar, Pub Med, Pub Med Central, Science Direct, and Scopus were used to find relevant studies by using keywords such as "mandibular canal", "alveolar canal", "inferior alveolar nerve canal", "inferior dental canal", "inferior mandibular canal" and "displacement". Results: About 120 articles were found, of which approximately 70 were broadly relevant to the topic. We ultimately included 37 articles that were closely related to the topic of interest. When the data were compiled, the following 8 lesions were found to have a relationship with displacement of mandibular canal: radicular/residual cysts, dentigerous cyst, odontogenic keratocyst, aneurysmal bone cyst, ameloblastoma, central giant cell granuloma, fibrous dysplasis, and cementossifying fibroma. Conclusion: When clinicians encounter a lesion associated with displaced mandibular canal, they should first consider these entities in the differential diagnosis. This review would help dentists make more accurate diagnoses and develop better treatment plans according to patients' radiographs.

• Journal of Yeungnam Medical Science
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• v.39 no.2
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• pp.161-167
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• 2022

Congenital web formations are extremely rare anomalies of the extrahepatic biliary tree. We herein report a case of common bile duct septum combined with multiple intrahepatic bile duct strictures in a 74-year-old female patient who was successfully treated with radiological intervention. The patient initially visited the hospital because of upper abdominal pain. Imaging studies revealed multifocal strictures with dilatation in both intra- and extrahepatic ducts; the final clinical diagnosis was congenital common bile duct web combined with multiple intrahepatic duct strictures. Surgical treatment was not indicated because multiple biliary strictures were untreatable, and the disease was clinically diagnosed as benign. The multiple strictures were extensively dilated twice through bilateral percutaneous transhepatic biliary drainage (PTBD) for 2 months. After 1 month of observation, PTBD catheters were successfully removed. The patient is doing well at 6 months after completion of the radiological intervention, with the maintenance of normal liver function. Congenital web of the bile duct is very rare, and its treatment may vary depending on the patterns of biliary stenosis. In cases where surgical intervention is not indicated for congenital web and its associated disease, radiological intervention with balloon dilatation can be a viable therapeutic option.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.153-153
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• 2006

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.7-12
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• 2004

Purpose: To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. Materials and Methods: 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. Results: The mean length of incisive canal was 15.87 mm±2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm±0.76 and 3.89 mm± 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3°±6.96 and 117.45°±7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r= 0.258). Conclusion : This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.35-48
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• 2004

Purpose: To investigate the effect of rhBMP-2 on the healing of bone defect in the low calcium diet rat. Materials and Methods: To prepare the experimental model, control group was fed a normal diet and experimental group was fed a low calcium diet for 3 weeks. And then, 4 mm bicortical perforated bone defect was made on mandibular body of each rats. Experimental group was subdivided into two groups; experimental group 1 (rats given a low calcium diet before and after bone defect) and experimental group 2 (rats given a low calcium diet before and after bone defect with rhBMP-2 application). At 1, 3, 5 and 7 weeks after bone defect formation, the rats were terminated. The healing of bone defect was assessed by three-dimensional computerized tomography, soft x-ray radiography, and histopathological examination. Results : The wound healing of the bone defect for control group, experimental group 1, and experimental group 2 showed a increase from 3 weeks after bone defect formation. The experimental group 2 showed a more increase in healing amount than control group and experimental group 1 from 5 weeks after bone defect formation and the experimental group 2 showed a complete recovery of bone defect at 7 weeks after bone defect formation. Conclusion: The healing process of bone defect is accelerated by rhBMP-2 application in the low calcium diet rats.