• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.29-39
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• 2024

Background: The gamma emission tomography (GET) device has been reported a reliable technique to inspect partial defects within spent nuclear fuel (SNF) of pin-by-pin level. However, the existing GET devices have low accuracy owing to the high attenuation and scatter probability for SNF inspection condition. The purpose of this study is to design and optimize a Yonsei single-photon emission computed tomography version 2 (YSECT.v.2) for fast inspection of SNF in water storage by acquisition of high-quality tomographic images. Materials and Methods: Using Geant4 (Geant4 Collaboration) and DETECT-2000 (Glenn F. Knoll et al.) Monte Carlo simulation, the geometrical structure of the proposed device was determined and its performance was evaluated for the ¹³⁷Cs source in water. In a Geant4-based assessment, proposed device was compared with the International Atomic Energy Agency (IAEA)-authenticated device for the quality of tomographic images obtained for 12 fuel sources in a 14 × 14 Westinghouse-type fuel assembly. Results and Discussion: According to the results, the length, slit width, and septal width of the collimator were determined to be 65, 2.1, and 1.5 mm, respectively, and the material and length of the trapezoidal-shaped scintillator were determined to be gadolinium aluminum gallium garnet and 45 mm, respectively. Based on the results of performance comparison between the YSECT.v.2 and IAEA's device, the proposed device showed 200 times higher performance in gamma-detection sensitivity and similar source discrimination probability. Conclusion: In this study, we optimally designed the GET device for improving the SNF inspection accuracy and evaluated its performance. Our results show that the YSECT.v.2 device could be employed for SNF inspection.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.69-72
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• 2015

This study was performed to differentiate calcium oxalate and struvite canine urinary stones using computed tomography. A total of 38 urinary stones (8 calcium oxalate and 30 struvite) were scanned using a computed tomography scanner. These urinary stones (10-15 mm diameter) extracted surgically without fragmentation were obtained from the different individual patients. The stone's Hounsfield units(HU) values, heterogenicity, and roughness of surface were evaluated to differentiate calcium oxalate and struvite. The HU values of calcium oxalate were significantly higher than those of struvite. A receiver operator characteristic (ROC) curve revealed 1272 as the best threshold value to distinguish calcium oxalate from struvite (ROC curve AUC 0.87, p < 0.0014). The heterogenicity of calcium oxalate and struvite significantly differed on bone and dental window setting (p < 0.0001). There was no significant difference between calcium oxalate and struvite in roughness of surface. On computed tomographic images, bone and dental windows setting were useful for evaluation of heterogenicity between calcium oxalate and struvite. The HU value and heterogenicity are highly promising factor that can distinguish calcium oxalate and struvite with reasonable accuracy.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.290-293
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• 2018

Signalment: A dog which had been hit by car a month prior and had been experiencing recurrent pleural chyle effusion was referred to Chung-buk National University Animal Medical Center. The clinical signs included tachypnea and salivation. Results: Ultrasound-guided popliteal lymphography was performed. The computed tomography imaging revealed that the thoracic duct was ruptured and the lymph was leaking into the cranial mediastinal region. After this discovery, thoracic duct ligation was performed. The ultrasound-guided popliteal lymphography was repeated after the surgery. The second computed tomography imaging revealed that the thoracic duct rupture was resolved. Clinical relevance: We identified the etiology of chylothorax through the computed tomographic lymphography and imaged specific leakage areas. After surgery, the computed tomography imgaing confirmed the lymphatic flow modification and the treatment was successful.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.7-12
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• 2014

Purpose Surgical correction of various occular problems which do not have visual problem in plastic surgical area is to normalize the appearance of the face by restoring the normal position of orbit and eyeball. With development of surgical technique, the orbit can be restored exactly in trauma patient and can be moved totally in hypertelorism, as an example of congenital disease. All these surgeries are based on the hypothesis that the position of oclular glove moves in the plane in a quantitatively predictable reationship to osseous orbit movement. However, no studies have critically evaluated between the change of periorbital soft tissue and the outcome of the surgical correction, because there is no method of objective, quantitave evaluation of the periorbital soft tissue. Method Author suggest the methodology for quantitative assessment of ocular and periocular fat changes using the manipulation of digital images of computed tomographic scan. Results The method was allowed to evaluate inter-dacryon distance, inter-centroid distance, movement of the medial orbital wall, movement of the lateral orbital wall, alteration of thickness of the lateral periorbital fat as indicator of movement of the orbital wall and orbit in the patient with congenital periorbital anomaly and postoperative periorbital surgery. The goal of surgical correction of various occular problems which do not have visual problem in plastic surgical area is to normalize the appearance of the face by restoring the normal position of orbit and eyeball. With development of surgical technique, the orbit can be restored exactly in trauma patient and can be moved totally in hypertelorism, as an example of congenital disease. All these sugeries are based on the hypothesis that the position of oclular glove moves in the plane in a quantitatively predictable relationship to osseous orbit movement. However, no studies have critically evaluated between the change of periorbital soft tissue and the outcome of the surgical correction, because there is no method of objective, quantitave evaluation of the periorbital soft tissue. In this report, author suggest the methodology for quantitative assessment of ocular and periocular fat changes using the manipulation of digital images of computed tomographic scan. Conclusion The method suggested is objective and accurate method in measurement of the orbital contents. It takes time and is not easy to do, however, this kind of measurement for fine structures will be more easily available in near future.

• Journal of Biomedical Engineering Research
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• v.3 no.1
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• pp.51-54
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• 1982

As the computerized methods and equipments in nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected profiles of radioisotope distribution from the quantitative point of view, and reduced the filter Parameters such as cutoff frequency and order of filter which are necessary to minimize the quantification error using computer -generated phantoms.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2008.10a
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• pp.188-188
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• 2008

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.67-73
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• 1988

This study was performed to clarify the mechanism of clicking sound and locking on temporomandibular joint and to determine the radiographic findings of them by using computed tomogram. Through the preliminary study with cadavers, the proper scanning condition and the correlatonship between the anatomy of cadaver and computed tomogram had been determined. The subjects were consisted of 10 controls and 16 patients having clicking sound or locking on temporomandibular joint. By using Hitachi-W500 as computed tomographic device, direct axial views and sagittal views reformed according to the changes in window setting and using the non-linear fraction were taken and analyzed by visual method and measuring the attenuation numbers. The obtained results were as follows: 1. The density of the anterior band of meniscus showed isodense to the surrounding muscles in normal. 2. In patient group, affected side showed increased radiopaque area anterior to condyle and underneath articular eminence as the feature of anteriorly displaced meniscus on axial and sagittal views. 3. In patient group, the condyle was rotated postero-laterally in affected side. 4. Non-linear fraction highlightened the feature of anteriorly displaced meniscus.

• The Journal of the Korean dental association
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• v.52 no.12
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• pp.753-761
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• 2014

Purpose: This study was performed to examine distribution of accessory mandibular canal and its characteristics in mandibular third molars. Materials and methods: A total of 251 subjects (166 males and 85 females) having mandibular third molars bilaterally were included in the study. Cone-beam computed tomographic images were reviewed for bifid or trifid accessory mandibular canal. The prevalence of accessory mandibular canal was evaluated according to gender, side and its branching type. Proximity and crosssectional position of accessory mandibular canal to mandibular third molar was analyzed. Results: Accessory mandibular canals were found in 66 (26.3%) of 251 patients and 86 (17.1%) of 502 hemi-mandibles. Gender and sides showed no statistically significant differences in prevalence. Retromolar canal (46.1%) was the most common branching type. Proximity of accessory canal to mandibular third molars showed mean distance of 2.8 mm from third molar and a statistically significant difference was found among types of accessory canal. Dental canal was the closest to tooth among branching types and closer to tooth than main canal. On cross-sectional view, accessory canal was generally located on buccal side of mandibular third molar. Conclusion: Accessory mandibular canal was common and well detected with cone-beam computed tomography. Their localization is significant in all anesthetic and surgical procedures involving mandibular third molars.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.399-402
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• 2003

A female unknown aged Yorkshire terrier, weighing 3.5 kg with nasal discharge, left facial swelling and severe inflammation was referred to Veterinary Medical Teaching Hospital, Seoul National University. Radiographic findings were lytic change and soft tissue swelling of left zygomatic process and increased radiopacity of nasal cavity. In computed tomography, turbinate bone destruction was observed as well as lytic change of left zygomatic process and left maxilla indicating aggressive lesion. Then 3-dimensional reconstruction was also performed. Biopsy of tissue mass revealed it as squamous cell carcinoma. For this patient, euthanasia was performed guarded prognosis. Generally, tumors of the nasal cavity in dogs account for approximately 1 % to 2% of all neoplasms. The prevalence of these tumors increased with age and exposure to the ultraviolet. About two thirds of all nasal tumors are malignant tumors such as squamous cell carcinoma and adenocarcinoma. As these tumors of nasal cavity are locally invasive, and external beam radiotherapy is the current treatment of choice. Unfortunately, diagnosis of these tumors often occurs late in the course of disease, resulting in a poor prognosis for outcome in many patients. It is considered that computed tomography could be used as an aid modality for the exact evaluation of extend and degree of bone lysis of nasal cavity and metastasis.

• Imaging Science in Dentistry
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• v.50 no.4
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• pp.331-337
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• 2020

Purpose: As cone-beam computed tomography (CBCT) has become the most widely used 3-dimensional (3D) imaging modality in the dental field, storage space and costs for large-capacity data have become an important issue. Therefore, if 3D data can be stored at a clinically acceptable compression rate, the burden in terms of storage space and cost can be reduced and data can be managed more efficiently. In this study, a deep learning network for super-resolution was tested to restore compressed virtual CBCT images. Materials and Methods: Virtual CBCT image data were created with a publicly available online dataset (CQ500) of multidetector computed tomography images using CBCT reconstruction software (TIGRE). A very deep super-resolution (VDSR) network was trained to restore high-resolution virtual CBCT images from the low-resolution virtual CBCT images. Results: The images reconstructed by VDSR showed better image quality than bicubic interpolation in restored images at various scale ratios. The highest scale ratio with clinically acceptable reconstruction accuracy using VDSR was 2.1. Conclusion: VDSR showed promising restoration accuracy in this study. In the future, it will be necessary to experiment with new deep learning algorithms and large-scale data for clinical application of this technology.