• Journal of radiological science and technology
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• v.45 no.2
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• pp.127-134
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• 2022

In order to overcome the image quality limitations of the conventional C-arm, a flat panel detector (FPD) is used to enhance spatial resolution, detective quantum efficiency, frame rate, and dynamic range. Three-dimensional (3D) visualized information can be obtained from C-arm computed tomography (CT) equipped with an FPD, which can reduce patient discomfort and provide various medical information to health care providers by conducting procedures in the interventional procedure room without moving the patient to the CT scan room. Unlike a conventional C-arm device, a C-arm CT requires different basic safety and essential performance evaluation criteria; therefore, in this study, basic safety and essential performance evaluation criteria to protect patients, medical staff, and radiologists were derived based on International Electrotechnical Commission (IEC) standards, the Ministry of Food and Drug Safety (MFDS) standards in Korea, and the rules on the installation and operation of special medical equipment in Korea. As a result of the study, six basic safety evaluation criteria related to electrical and mechanical radiation safety (leakage current, collision protection, emergency stopping device, overheating, recovery management, and ingress of water or particulate matter into medical electrical (ME) equipment and ME systems: footswitches) and 14 essential performance evaluation criteria (accuracy of tube voltage, accuracy of tube current, accuracy of loading time, accuracy of current time product, reproducibility of radiation output, linearity and consistency in radiography, half layer value in X-ray equipment, focal size and collimator, relationship between X-ray field and image reception area, consistency of light irradiation versus X-ray irradiation, performance of the mechanical device, focal spot to skin distance accuracy, image quality evaluation, and technical characteristic of cone-beam computed tomography) were selected for a total of 20 criteria.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.429-437
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• 2023

In veterinary medicine, most radiographic images are obtained by restraining patients, inevitably exposing the restrainer to secondary scattered radiation. Radiation exposure can result in stochastic reactions such as cancer and genetic effects, as well as deterministic reactions such as skin burns, cataracts, and bone marrow suppression. Radiation-shielding equipment, including aprons, thyroid shields, eyewear, and gloves, can reduce radiation exposure. However, the risk of radiation exposure to the upper arms, face, and back remains, and lead aprons and thyroid shields are heavy, restricting movement. We designed a new radiation-shielding system and compared its shielding ability with those of conventional radiation-shielding systems. We hypothesized that the new shielding system would have a wider radiation-shielding range and similar shielding ability. The radiation exposure dose differed significantly between the conventional and new shielding systems in the forehead, chin, and bilateral upper arm areas (p < 0.001). When both systems were used together, the radiation-shielding ability was better than when only one system was used at all anatomical locations (p < 0.01). This study suggests that the new radiation-shielding system is essential and convenient for veterinary radiation workers because it is a step closer to radiation safety in veterinary radiography.

• The Journal of the Korean dental association
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• v.50 no.4
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• pp.196-202
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• 2012

Radiographic diagnosis of periapical lesions is based on many factors, including anatomical limitations such as thickness of the cortical bone; positioning of the apical abscess to the cortical bone; and is complicated by proximity to other anatomical structures and neighboring teeth. With conventional radiographs, these structures are often superimposed. Dental CBCT with its associated geometric accuracy offers accurate visualizations of the complex relationships and boundaries between teeth, related anatomical features, and their associated pathology. Its images also provide us internal tooth morphology, periodontal ligament space, the presence or absence of periapicl lesions in association wi th critical anatomical structures and maxillary sinus involement. Using 3 D imaging makes it easier for clinicians to detect, diagnosis, and develop highly effective treatment plans. Now, 4 cases of periapical and periodontal pathosis with CBCT images are to be presented including periapical abscess, furcation involvement, periapical pathosis involving maxillary sinus, and osteomyelitis. CBCT analyze specific area of interest and provides the highly detailed anatomical information. It also facilitates earlier and more accurate diagnosis, and treatment planning decisions and more predictable outcome.

• Physical Therapy Korea
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• v.15 no.4
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• pp.64-69
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• 2008

The purpose of this study was to compare the effectiveness of modified vertical roll sling and conventional Bobath roll sling in reducing hemiplegic shoulder subluxation. Radiography of $40^{\circ}$ anterior oblique radiographic view' were taken, before and immediately after wearing each sling in 13 hemiplegic patients. The vertical distance. horizontal distance. and joint distance were measured. Analysis of radiographically measured distances showed that both modified vertical roll sling and Bobath roll sling decreased vertical, horizontal. and joint distances. Reduction in vertical and joint distances were significantly greater in modified vertical roll sling compared to Bobath roll sling. while horizontal distance showed no significant difference between the two slings. Therefore it can be concluded that modified vertical roll sling is an effective orthosis in reducing hemiplegic shoulder subluxation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.24.1-24.5
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• 2019

Background: Conventionally, indirect radiography has been used to diagnose salivary gland diseases. However, with the development of sialendoscopy, diagnosis and treatment of salivary gland diseases have become more effective. Herein, we report a case of sialolithotomy treated with sialendoscopy and compare it with the existing methods through a literature review. Case presentation: Two patients with a foreign body sensation under the tongue and dry mouth visited the Anam Hospital, Korea University. Radiographic examination revealed salivary stones inside the right Wharton duct, and the patients underwent sialolithotomy under local or general anaesthesia. The stones were totally removed, and there were no postoperative complications such as bleeding or pain. Conclusion: The development of sialendoscopy has enabled better definitive diagnosis of salivary gland diseases compared with the conventional methods; better treatment outcomes can be obtained when sialendoscopy is used in appropriate cases.

• The Journal of the Korean dental association
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• v.52 no.3
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• pp.132-138
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• 2014

The emergence of Cone Beam Computed Tomography(CBCT) in the late 1990s represented an innovative advancement in the field of dental and maxillofacial radiology because it greatly reduced the radiation exposure to patients and offered 3D images easily. The 3D information generated by this technique brings the potential of improved diagnosis and treatment planning for a wide range of clinical applications in dentistry. The use of CBCT includes diagnosis and surgical assessment of the orofacial hard tissue lesions, dental implant treatment planning and postoperative evaluation, TMJ assessment, diagnosis of craniofacial fracture, orthodontics, endodontics, and so on. All CBCT examinations should be justified on an individualized needs. The clinical benefits to the patient for each CBCT scan must outweigh the potential risks associated with exposure to ionizing radiation. CBCT scans should be taken with initially obtained medical and dental histories of patients and a close clinical examination. CBCT should be considered as an imaging alternative of other conventional radiography in cases where the anatomical structures of interest may not be seen. The smallest possible field of view(FOV) and the lowest setting of tube current and scan time should be chosen, and the entire images scanned should be interpreted by a qualified expert.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.436-438
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• 2002

As the use of virtual simulation expands, digitally reconstructed radiographs (DRRs), which mimic conventional simulation films, play an increasingly important role as reference images in the verification of treatment fields. The purpose of our study is to develop an algorithm for computation of digitally reconstructed radiographs based on Monte Carlo simulation that take into account almost all possible physical processes by which photons interact with matter. The Monte Carlo simulation based DRRs have the following features. 1) Account has been taken of almost all possible physical processes of interaction of photons with matter, including a detector (film) response. In principle, this is equivalent to X-ray radiography. 2) Arbitrary photon energies (from diagnostic to therapeutic) can be used to produce DRRs. One can even use electrons as the source. 3) It is easy to produce a double exposure, which mimics the double exposure portal image and may have superior visual appeal for treatment field verification, with weighting within the treatment field.

• Journal of Biomedical Engineering Research
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• v.30 no.6
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• pp.476-481
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• 2009

The most troublesome artifacts in micro computed tomography (micro-CT) are ring artifacts. The ring artifacts are caused by non-uniform sensitivity and defective pixels of the x-ray detector. These ring artifacts seriously degrade the quality of CT images. In flat-panel detector based micro-CT systems, the ring artifacts are hardly removed by conventional correction methods of digital radiography, because very small difference of detector pixel signals may make severe ring artifacts. This paper presents a novel method to remove ring artifacts in flat-panel detector based micro-CT systems. First, the bad lines of a sinogram which are caused by defective pixels of the detector are identified, and then, they are corrected using a cubic spline interpolation technique. Finally, a ring artifacts free image is reconstructed from the corrected projections. We applied the method to various kinds of objects and found that the image qualities were much improved.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.79-85
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• 1998

Changes in the human voice occur between infancy and old age and reflect a myriad of biological changes that influence the size, shape, and physical properties of the larynx. The human larynx is located near the base of the neck and attached inferiorly to the trachea and opens superiorly into the pharynx. The larynx by the third month of fetal life has the same features recognizable at birth. The fundamental frequency of vocal fold vibration generally becomes higher in early age, lower in middle age, and higher in old age. These decreases in Fo undoubtedly result from a combination of factors, consisting of modest increase in length and mass of the muscle and connective tissues of the vocal fold. But the level of the larynx in the neck may be closely connected with Fo directly, high larynx in related with high pitch and low larynx with low pitch. The purpose of this study is to determine the developmental level difference from child to adult larynx using conventional radiography, and the change of speaking fundamental frequency from second decade to sixth decade.

• Imaging Science in Dentistry
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• v.36 no.3
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• pp.163-168
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• 2006

A 60-year-old female, who complained of delayed healing and swelling after extraction of left lower second molar during chemotherapy, visited our department. She had a history of a resection surgery of breast cancer and postoperative radiotherapy. The conventional radiographs showed diffuse permeative bone destruction in posterior mandibular body, which gave the first radiologic impression of osteonecrosis associated with radiotherapy or chemotherapy. And bone metastasis from the breast cancer was also considered in the differential diagnosis. On the enhanced computed tomography (ECT) the posterior mandibular body was occupied by a large expansile lesion showing central low attenuation with peripheral rim enhancement. Magnetic resonance images revealed that the low attenuated area on ECT did not show as high signal intensity as water on T2 weighted image and indicated solid component of a tumor. The final diagnosis was central squamous cell carcinoma. We present the diagnostic imaging features of the patient with special emphasis on the differential diagnosis.