• Imaging Science in Dentistry
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• v.36 no.3
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• pp.123-129
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• 2006

The use of computed tomography for dental procedures has increased recently. Cone beam computed tomography (CBCT) systems have been designed for imaging hard tissues of the dentomaxillofacial region. CBCT is capable of providing high resolution in images of high diagnostic quality. This technology allows for 3-dimensional representation of the dentomaxillofacial skeleton with minimal distortion, but at lower equipment cost, simpler image acquisition and lower patient dose. Because this technology produces images with isotropic sub-millimeter spatial resolution, it is ideally suited for dedicated dentomaxillofacial imaging. In this paper, we provide a brief overview of cone beam scanning technology and compare it with the fan beam scanning used in conventional CT and the basic principles of currently available CBCT systems.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.819-825
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• 2020

The purpose of this study was to evaluate the usefulness of the developed air mattress for reducing the deterioration of image quality due to the scattered radiation generated on the computed tomography equipment table. 5 cm and 10 cm thick air mattresses were developed and the image quality was measured by scanning the AAPM phantom according to thickness and thickness. Statistical significance was confirmed by One Way Analysis of Variance(ANOVA) Compared with the AAPM phantom scanned in the standard method, the image with the air mattress did not show any difference, but when the air mattress was not applied, the CT number and uniformity were low and the noise was high, and the spatial resolution Respectively. The developed air mattress has no harmful effect on the diagnostic image, it is very effective in improving the image quality and can increase the CT image quality by simply applying Air Mattress to existing equipment without using the technology applied to the latest and high-cost equipment.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.109-115
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• 2015

In case of a CT examinations, there is a difference in the distribution of radiation dose from that of general X-ray equipments, and it has been known to cause a great radiation exposure during the examinations. However, owing to its high reliability on the accuracy of a examinations result, its use has increased continuously. In consideration of such a circumstance, the CT equipment, radiation dose during CT examinations, diagnostic reference level, and solutions to reduce radiation dose were mentioned on the basis of previously reported data.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.221-233
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• 2020

CT(computed tomography, CT) examinations is one of the most useful diagnostic equipment for identifying information in the human body in diagnostic radiology. Recently, the number of CT scans is increasing every year due to the high reliability of CT scans. Increasing the number of tests will accelerate the aging of CT devices, which is why the importance of quality management for CT devices is on the rise. Particularly in CT, quality management refers to a behavior of figuring out and correcting all sorts of hindrance factors that can cause all the problems related to the equipment associated with the diminishment of diagnosed area due to the reduction of image quality in clinical imaging in advance and maintaining a consistent level of image quality and obtaining a proper image. Here, these researchers aim to summarize and report the general contents of quality management in CT.

• 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 the Korean Society of Radiology
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• v.11 no.6
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• pp.453-458
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• 2017

Computed Tomography (CT) provides information on the Diagnostic Reference Level Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP) for accurate diagnosis of patients. However, it does not provide a dose change according to the table height for the diagnostic reference level provided by the CT equipment. The purpose of this study was to evaluate the image and dose according to the table height change using phantom (PMMA: Polymethyl Methacrylate) in order to find the optimal image and the minimum dose during computed tomography examination. When examining using a 32 cm PMMA phantom with the same thickness as the abdomen of an adult, there was little change in dose with table height. However, the noise evaluation of the image caused a high fluctuation of noise depending on the table height. and in the case of the 16 cm PMMA phantom, the change of the noise was small, but the dose change was about 30%. In conclusion, the location of the patient and the center of the detector are important during computed tomography (CT) examinations. In addition, table height setting is considered to be important for examinations with optimized image and minimum dose.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.225-230
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• 2010

The purpose of the study was to apply and to expand the six sigma to reduce waiting times for computed tomography (CT) examination which manipulated by the department of radiology. It was preceded by DMAIC (Define, Measure, Analyze, Improve, and Control). In the stage of definition, it wereselected for total 5 critical to quality (CTQ), which were the kindness, the waiting time, the examination explanation, the waiting day and the waiting stand environment, that increased the reserved time of CT examination. In the stage of measurement, the number of examinations and of reservation waiting days performed and resulted in final CTQ(Y) which measured each 1.68 and 1.85 sigma. In the stage of analysis, the examination concentrated on morning time, non-scheduled examination of the day, the delayed time of booking, frequent telephone contacting and equipment malfunction were determined as variable key causes. In the stage of improvement, it were performed with expansion of the examination in the morning time, integration of laboratories that used to in each steps, developing the ability of simultaneous booking schedule for the multiple examinations, developing program of examination request, and the customer management team operations. For the control, the number of examinations and reserved waiting days were measured each 3.14 and 1.13 sigma.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.581-586
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• 2018

This study was conducted to analyze factors Influencing Protective Behavior against Radiation Exposure using questionnaires for 231 radiological technologists working in Computed Tomography(CT) examination room with high radiation dose in diagnostic radiology field. Statistical analysis of the collected data revealed that the reasons for partially shielding the examination part in the CT scan were the lack of protective equipment, securing of radiation justification, being annoying and maybe not being harm to adults in order. It was also revealed that the variables influencing the protective behavior were protective behavior against radiation harm, self-efficacy, protective environment, organization culture, protective knowledge and protective instrument in order. The higher the radiological protective environment(${\beta}=0.245$) and the lower the radiological protective knowledge(${\beta}=-0.034$), the more influential the protective behavior against radiation harm was. In this study, it was shown that non examination parts were not shielded in the CT scan. Therefore, it is necessary to improve the level of protective environment, to cultivate knowledge to improve the protective behavior against radiation harm and to have an intervention strategy for concrete action.

• Journal of radiological science and technology
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• v.8 no.2
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• pp.29-45
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• 1985

Computed Tomography Scanner (CT) is highly expensive in operation as well as purchasing. That reason may cause not only to increase the burden of patients but also to waste the capital resources leading to financial difficulties. However the numbers of CT installed throughout the country is increasing, because of efficiency in medical care, patient's concern, competitions among the hospitals within the same area. In the non-Metropolitan area the scanners were expected to be less utilized and less profitable. Nine hospitals equipped with the CT were studied on the utilization of that equipment during the period from November 1984 to February 1985 in non-Metropolitan area and break-even point in one hospital was analyzed for estimating profitabilities. The results were as follows ; 1. Among those nine hospitals, four hospitals had less than 400 beds, which is one of the restrictive minimum standards on the installation of Whole-body Computed Tomography Scanner. 2. The operating time during the normal operation period was longer than those of any other studies, but the accumulated down time was also longer than those of any other studies. The average number of scanning per week for each CT was 45, while the estimated number of for the break-even point was 56.7 cases. 3. When the downtime was excluded in calculating the average operation would be much closer to the cases for the break-even point. Therefore the break-down of the equipment was to be a main cause of the low profitability. 4. The average scanning rate for head area was 33.6%, however three of the nine hospitals showed about 20%. 5. If scanning ratio for the body parts excepting head was increased, the number of scanning for the break-even point would be diminished. 6. The small size hospital especially located near the Metropolitan area showed largest loss in the CT operation. In purchasing the highly expensive equipments in hospitals, demand should be taken into account and planning is recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6932-6939
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• 2015

The respiration is one of important factor in the radiation therapy. The existing commercial method of cone-beam computed tomography on LINAC does not consider respiratory motion of patient hence the images are both distorted and inaccurate. In this study, the cone-beam computed tomography images have been reconstructed from back projection radiography of specific phase on breathing cycle which concerned about respiratory movement in radiation therapy. This study investigated how different between cone-beam CT images with and without gating respiratory movement, and this paper provides that guide and implementation of gated cone-beam CT on radiation therapeutic equipment.