• Journal of radiological science and technology
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• v.42 no.1
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• pp.19-24
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• 2019

For general radiological examinations, even in the same area and the same test, the test conditions must be set differently according to the patient. However, since it is impossible to consider the body shape and conditions of patients every time in medical institutions where various patients visit, the tests are conducted by setting the AEC which automatically sets the test conditions. AEC is most commonly used in chest radiography. Therefore, the purpose of this study is to propose the improvement plans for using AEC by measuring the exposure dose and evaluating the image quality according to whether the AEC is used or not, and to provide basic data for AEC research. In the present study, images were acquired while varying tube voltage and test distance according to the use of AEC in chest radiography. The radiation dose was measured by placing the dosimeter in front of the chest phantom, and the CNR and SNR of acquired images were analyzed using Image J. The t-test was conducted for the statistical analysis and the significance was determined at the level of 95%(p<.05). As a result of this study, in the inspection distance (100cm, 140cm, 180cm) according to the use of AEC, high doses were observed when the AEC was used and there was statistically significant difference(p<.05). In the t-test to determine the difference between CNR and SNR depending on whether AEC was used or not, there was no significant difference according to the use of AEC(p>.05). Therefore, when performing chest radiography, if the radiologist establishes the appropriate examination conditions and conducts the examination by not just relying solely on AEC, it may be possible to reduce unnecessary radiation exposure to the patient.

• Journal of radiological science and technology
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• v.20 no.2
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• pp.49-55
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• 1997

This study was carried out to investigate radiographical and operating conditions of X-ray units and exposure doses to patients during chest radiography, so that the results could provide basic data used for reducing the exposure dose and for providing the diagnostic information with better quality. The conditions and exposure doses of 100 X-ray units mainly used for chest radiography were examined and also 100 radiological technologists mainly handling those apparatus at 76 medical facilities in Pusan were surveyed using a questionnaire from October 1 to December 31 in 1995. The following results were obtained from the study : 1. It was found that most units were capable of taking a high tube voltage radiography by showing 67% of the units equipped with the maximum tube voltage of 150 kV, 94% with more than 500 mA for the rating capacity and 85% with the full wave type of a signal phase. 2. For actual chest radiographical conditions, however, 80% of the units were operated at $60{\sim}100\;kVp$ and only 14% at 100 kVp and over for the high tube voltage. 3. The average exposure time was less than 0.1 second, and eighty four percent of the units adapted the X-ray tube currents ranging from 200 to 300 mA, 80% the focus-film distances between 180 and 210 cm, and 63% the focus sizes of more than 2.0 mm. 4. Most units(98%) employed additional filters made of aluminum, 75% the thickness of filters less than 2.0 mm, and only 2 units the compound filters. 5. Ortho chromatic system was only adopted in 13% of screen film system for the units, and 73% used the grid ratio at 8 : 1 for the low tube voltage during chest radiography. 6. The average exposure dose of all X-ray units during chest radiography was $371\;{\mu}Sv$ with a difference of about 16 times between the minimum to the maximum, and $386\;{\mu}Sv$ both at hospitals and at health centers, followed by $380\;{\mu}Sv$ at general hospitals and $263\;{\mu}Sv$ at university hospitals without showing any statistically significant differences. In conclusion, since patients during chest radiography at medical facilities in Pusan exposed to high levels of radiation, it is recommended that appropriate added filters and grids necessary for the high tube voltage radiography and high-speed screen systems should be adopted and used as soon as possible in order to reduce exposure dose to the patients.

• Journal of Korean Foot and Ankle Society
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• v.6 no.1
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• pp.111-116
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• 2002

Synovial chondromatosis is an uncommon benign lesion characterized by metaplastic cartilage formation within the synovial connective tissue, usually intraarticular, commonly affects the knee, hip and elbow. An extraarticular lesion is rare, most often seen in a synovial sheath and bursa of the hand or foot. We present a case of extraarticular synovial chondromatosis in the left ankle, originated from the FHL tendon sheath of a 31 year-old-female diagnosed by a radiography, MRI confirmed histopathologically.

• Imaging Science in Dentistry
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• v.42 no.1
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• pp.1-4
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• 2012

Purpose : Hand-held dental x-ray system is a self contained x-ray machine designed to perform intraoral radiography with one or two hands. The issue about its usage as general dental radiography is still in dispute. The aim of the present study was to assess the relationship between the amount of battery charge and the tube voltage in different handheld dental x-ray systems. Materials and Methods : Seven hand-held dental x-ray units were used for the study. Tube voltage was measured with Unfors ThinX RAD (Unfors Instruments AB, Billdal, Sweden) for 3 consecutive exposures at the different amount of battery charge of each unit. The average and the deviation percentage of measured kV from indicated kV of each unit were calculated. Results : Tube voltage of only 1 unit was 70 kV (indicated by manufacturer) and those of the others were 60 kV. Tube voltage deviation percentage from the indicated kV at the fully charged battery was from 2.5% to -5.5% and from -0.8% to -10.0% at the lowest charged battery. Conclusion : Tube voltages of all units decreased as the residual amount of the battery charge decreased. It is suggested that the performance test for hand-held x-ray system should be performed for the minimum residual charged battery as well as the full charged one. Persistent battery charging is suggested to maintain the proper tube voltage of the hand-held portable x-ray system.

• Journal of radiological science and technology
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• v.23 no.2
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• pp.43-54
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• 2000

This paper will present the result of research which was done with 201 places on the actual condition of using dental diagnostic radiography unit and the protection of radiography. The purpose of this paper is to comprehend the actual condition of using dental x-ray unit and to protect when they do radiation work. Moreover this paper was completed to prepare basic materials that could be helpful to reduce the exposure from radiation. This paper obtains the following result. 1. On radiation photographing work in the dentist office, 50.3% of dental hygienists treat this job, and 19.2% of assistants, 10.8% of dentists, 5.6% of radiolotechnologists and 4.2% others performed this job. 2. The case that radiation worker is educated about diagnostic radiography safety supervision has been shown 14.4% and uneducated case has been shown 78.1%. 3. The result about the actual condition of using the oral diagnostic radiation per day was that a number of film which take photograph again (less than 1 exposure) was 40.3%. Normal photographing($1{\sim}10$ exposure) was 85.1% which is the highest percentage. Using the bitewing film and occlusal film was 7.0%, and 12.4% respectively. The percent that they use cephalo film and panoramic film was 16.4% 29.8% respectively. 4. Dental intra diagnostic radiography unit made in $1996{\sim}2000$ was 24.9% and the one made in $1991{\sim}1995$ was 19.9%, in $1986{\sim}1990$ was 19.9%, in 1985 was 9.5% according to the answer. On kVp, they use 60 kVp mostly(61.7%) and On mA, they use 10 mA with the highest percent(66.7%). On the dental extra diagnostic radiography units which are used for doing the extra oral radiography, the one made in $1996{\sim}2000$ was 13.4%, in $1991{\sim}1995$ was 9.5%, in $1985{\sim}1990$ was 2.0% according to the answer. They use $71{\sim}80\;kVp$ with 10.9% and $60{\sim}75\;kVP$ with 9.5%. They use less than 10 mA with 19.4% and $11{\sim}15\;mA$ with 2.5%. $16{\sim}20\;mA$ with 1.5%. But the case they exactly do not know how much mA they use or they do not have any mA was 76.6%. 5. General characteristics and the part of protection through the protective equipment by operator are completed with 89.1%. They have shown the similar difference in the relationship with age(p<0.001), experience(p<0.05) and in-patient(p<0.05). 6. When they take photographs of radiation with general quality, how far they keep the proper distance from the cone is as follows, Keeping safe distance is 12.9% according to the answer with the low percent. This result is similar with the difference related in experience(p<0.05) and work(p<0.05), the area of working(p<0.05) and in-patient(p<0.05). 7. The answer about the question-if they hold the tube head when they take photographs with general characteristics is as follows. The answer that they never hold the tube head and cone occupies 62.7% with the highest percent. It is shown the similar difference with age(p<0.05). 8. According to the study that they put on dosimeter with general characteristics is as follows. 64.7% has never put on the dosimester with the highest percent. 33.8% showed similar differences with experience(p<0.05), work(p<0.001), the area of work(p<0.005)and in-patient(p<0.001).

• Journal of radiological science and technology
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• v.41 no.3
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• pp.255-260
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• 2018

Most patients and parents and guardians display frequent anxiety due to radiation exposure during outpatient, ward, and pediatric general radiographic examinations. This is a behavior that perceives only the harmfulness of radiation. For the recognition of medical radiation, we conduct surveys on outpatients, inpatients, and pediatric parents and guardians to identify their awareness, and then use the radiation dose promotional materials After providing accurate information on the use of radiation, the outpatient, inpatient, and pediatric parents and guardians were asked to explain the change in awareness. The questionnaire items were classified into five categories: repetitive radiation awareness for diagnosis, awareness of exposure dose, availability of exposure information, awareness of radiation risk, and awareness of health problems caused by radiation. There was a statistically significant difference in the items of recognition result of medical radiation, although there was a slight difference in the individual items in the pre and post-recognition results of providing information about the radiologists of the protector and the outpatient(p<0.05). Therefore, through the installation of these promotional materials, we will improve our awareness of medical radiation safety during general radiography surveillance in the Department of Radiology to provide better quality medical information and medical services, thereby contributing to strengthening the competitiveness of the hospital.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.377-381
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• 2011

The purpose of this study is an assessment between the measured value of the nanoDot dosimeter and the calculated value of Non Dosimeter Dosimetry-Method(NDD-M) for entrance surface dose in general radiography. Measurement and calculation of the entrance surface doses were performed for head(AP), abdomen(AP), pelvis(AP), thoracic spine(AP) and lumbar spine(AP). As a result, the relative ratios of the measured value to the calculated value were acquired 1.5-2.1 for each region. Reproducibility acquired 0.035 as a coefficient of variation.

• Journal of radiological science and technology
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• v.44 no.6
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• pp.615-621
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• 2021

In the medical field, radiation provides information for the diagnosis and treatment of diseases. As the use of radiation increases and the risk of exposure increases, interest in radiation protection is also rapidly increasing. Lead shielding material is mainly used, which has a risk of lead poisoning and absorption into the body. Tungsten mixed filament shielding sheets were fabricated with a size of 70 × 70 mm and a thickness of 1, 2, and 4 mm by using a 3D printer. In the general shooting experiment, the thickness of the shielding sheet is 1 ~ 5mm, the tube voltage is 60, 80, 100, 120 kVp and the tube current is 20, 40 mAs. In general photography, Tungsten showed better shielding rate compared to Brass, Copper, and Lead protective tools under all irradiation conditions, and in particular, Tungsten 5 mm showed 100% shielding rate. The 3D-printed tungsten mixed filament shielding is expected to be used as a new shield that can replace the existing lead protection tools as it shows a better shielding rate than the existing lead protection tools in Radiography.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3347-3352
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• 2010

It is recommended that the door of control room is closed during radiography to protect a radiologic technologist. However, for those patients such as of emergency or pediatrics, the door must be kept open unavoidably to apply immediate medical administration and treatment on the potential case of emergency which could be happened through the course of radiography. In addition, it could be efficient by reducing patients waiting time when the door is open for a general case. This study was conducted to evaluate practical exposure rate to a radiologic technologist when the door is open during the radiography, and to find out the ways to minimize radiation exposure and to increase the efficiency simultaneously. Measuring practical exposure rate was fulfilled with glass dosimeter, and it was 2.02 mGy/week at the location of radiologic technologist under the condition that the door is open during the radiography, which was about 2.3 times higher than the 100 mR/week. It means that the considerable amount of scattered rays through the door opening, and increase exposure rate at the radiologic technologist. Hence we confirmed that a radiologic technologist probably overexposed if the door is open during the radiography. It was also confirmed by the Monte Carlo simulation that the exposure rate could be reduced up to approximately 1/100 by change only the door opening direction. In conclusion, since the proper door opening direction provides same shielding effect whether it is open or close, the door opening direction need to be considered when it is installed at radiography facilities.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.375-381
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• 2015

Digital Radiography is a big part of diagnostic radiology. Because uncorrected digital radiography image supported false effect of Patient's health care. We must be manage the correct digital radiography image. Thus, the artifact images can have effect to make a wrong diagnosis. We report types of occurrence by analyzing the artifacts that occurs in digital radiography system. We had collected the artifacts occurred in digital radiography system of general hospital from 2007 to 2014. The collected data had analyzed and then had categorize as the occurred causes. The artifacts could be categorized by hardware artifacts, software artifacts, operating errors, system artifacts, and others. Hardware artifact from a Ghost artifact that is caused by lag effect occurred most frequently. The others cases are the artifacts caused by RF noise and foreign body in equipments. Software artifacts are many different types of reasons. The uncorrected processing artifacts and the image processing error artifacts occurred most frequently. Exposure data recognize (EDR) error artifacts, the processing error of commissural line, and etc., the software artifacts were caused by various reasons. Operating artifacts were caused when the user didn't have the full understanding of the digital medical image system. System artifacts had appeared the error due to DICOM header information and the compression algorithm. The obvious artifacts should be re-examined, and it could result in increasing the exposure dose of the patient. The unclear artifact leads to a wrong diagnosis and added examination. The ability to correctly determine artifact are required. We have to reduce the artifact occurrences by understanding its characteristic and providing sustainable education as well as the maintenance of the equipments.