• Journal of the Korean Society of Radiology
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• v.18 no.6
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• pp.663-671
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• 2024

This study aims to evaluate the effects of Arm Height Angle (Arm Heiht Angle : AHA) on patient effective dose and image quality in lateral chest radiography, and to propose the optimal arm positioning for minimizing radiation exposure while ensuring diagnostic efficacy. Using consistent X-ray equipment with Automatic Exposure Control (AEC), examinations were performed on 10 patients at AHA settings of 90°, 120°, and 150°. For each angle, Dose-Area Product (DAP) values were measured, and effective dose was calculated using the Monte Carlo simulation-based software PCXMC 2.0. The findings revealed a 53% increase in effective dose when AHA was adjusted from 150° to 120°, although this difference was not statistically significant (p=0.3). However, setting the AHA to 90° resulted in an approximately 140% increase in effective dose, a statistically significant change (p=0.00). Quantitative assessment showed no statistically significant differences in image quality metrics across the 90°, 120°, and 150° groups, as measured by TT SNR (p=0.1), TT CNR (p=0.6), AA SNR (p=0.2), AA CNR (p=0.8), LA SNR (p=0.2), and LA CNR (p=0.8). Visual assessments indicated that the 150° AHA setting received the highest scores, suggesting that an arm height angle of 150° or greater may optimize image quality while reducing patient radiation exposure. Based on these results, this study recommends an AHA of 150° or higher as the optimal positioning for lateral chest radiography, providing an effective balance between radiation dose minimization and diagnostic image quality.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.807-812
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• 2018

In this study, we investigated the conditions used in setting the recommendation level of general radiography diagnostic reference and tried to evaluate the effective dose and biological evaluation using PCXMC v2.0 program. As a result based on the effective dose of male in ICRP 60, the highest Pelvis AP was 0.794 mSv. The lowest Chest PA was 0.050 mSv. In the case of ICRP 103, the highest T-Spine AP was 0.906 mSv The lowest Chest PA was 0.052 mSv. For 40 years old male and female adults, effective doses of general radiography were evaluated and even if the medical exposures are not subject to the limit of dose, efforts should be made to reduce the medical exposures of the people by keeping the dose below the recommended amount in order to minimize the probable effect of radiation hazard.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.433-438
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• 2015

To evaluate the radiation exposure level based on radiation workers' locations in dental radiography, the radiation dose rate in the radiographic room, lead glass, and operation system was measured. To that end, various devices were used, such as a Standard(Max-GLS, Shinhung), a panorama (PCH-2500, Vatech), a cephalometric radiography (PCH-2500), and a cone beam CT (PHT-30LFO, Vatech), as well as a PM1405 equipment as a radiation meter. Radiography conditions were set the same as the factors used in the clinical setting. As the result, the cone beam CT turned out the highest with 98 uSv and the standard showed the lowest level with 0.4 uSv/h. The panorama was measured to be higher than the Cephalo due to its different focus mode. On the lead glass surface and in the operation stand, the oral radiography device, panoramic, and Cephalo all were measured below the recording level. However, the cone beam CT was measured to have the leakage dose. Thus, radiation involved workers should be equipped with appropriate protection tools and reduce radiography time as much as possible. In addition, the structure of the radiation chamber should be also designed efficiently. Dental radiography has continued to grow in recent years, so it is necessary take appropriate protection measures for patients and radiation workers.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.919-927
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• 2018

The purpose of this study was to present simulation training model for general X-ray examinations and to analyze the errors that occur during the simulation training. From 2012 to 2018, a total of 183 students (77 men and 106 women) participated. The simulated X-ray system used computed radiography (CR) system. The contents of simulation training were patient's care, X-ray examinations accuracy, images stability, etc. As a result, it were found that the patient's position setting error, the accuracy error of the X-ray beam central ray, the image receptor's size and setting error, the error of the grid use, the marking error, and the error of X-ray exposure technical factors. It is expected that improved practical general X-ray examinations training of radiographer will be needed, focusing on these errors, so that we could contribute to the health care of the people by providing precise examinations and high quality medical service.

• Journal of the Korean Society of Radiology
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• v.8 no.2
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• pp.81-88
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• 2014

In diagnostic radiology, each part is examined through serial radiography in most cases of general radiography. However, the reality is that, as for diagnostic reference level, measured values have been set up only for AP projection of each part and lateral projection. In the clinical setting, cumulative dose is incurred by serial radiography of patients, and this can make comparison of diagnostic reference level and cumulative exposure dose impossible or can lead to underestimation of diagnostic reference level. In this study, measurement of cumulative dose of serial radiography of each part revealed that when converting entrance surface dose to effective dose in case it is included in the exposure field, cumulative dose measured from a maximum of 38.06% to a minimum of 0.23% of individual dose limitation of the public. Also, when converting entrance surface dose of each part that is not included in the exposure field into effective dose, it measured from a maximum of 5% to a minimum of 0.04% of individual dose limitation of the public. Results of this study show entrance surface dose substantially increases in serial radiography of each part. Therefore, it is deemed that hospitals need to establish diagnostic reference level specifically, and subdivision of radiography orders for patients is also required in order to reduce unnecessary inspections. Moreover, the need of accurate exposure field is emphasized in case of inspection of several parts.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.483-489
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• 2002

The computer simulation has been done for non-insulated and insulated pipes which are vacant or half filled with liquid. The simulation results showed that the density profile on the radiography is continuous and symmetrical around the center of pipe in the case of vacant pipe. On the other hand the density profiles are not symmetrical and depend on geometrical setting for radiography in the case of half filled pipes. Finally, experimental testing on a non-insulated carbon steel pipe with artificial notches of different depth is carried out using Ir-192 and industrial film. Comparing the measured density profile on the radiograph to the calculated one, it has been shown that it is possible to evaluate thickness variation by measuring density profile on a radiograph.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.421-426
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• 2011

This research was accomplished to assess dose effects on image quality at computed radiography (CR). The ultimate target of the research was finding optimized exposure that provides necessary image quality for the clinical chest diagnosis. Modulation transfer function (MTF), normalized noise power spectrum (NNPS), and Noise equivalent quanta (NEQ) corresponding to the different doses were measured for the assessment of image quality. The preparation of "edge test device" used in MTF measurement and experimental geometry setup were followed by the recommendations of International Electrotechnical Commission (IEC). The experimental results show the necessary image quality can be achieved even at a half of the automatic exposure control (AEC) setting dose for chest diagnosis. It means that the patient exposure can be reduced dramatically by using optimized dose.

• Journal of radiological science and technology
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• v.44 no.1
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• pp.1-8
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• 2021

The purpose of this study was to analyze the effect of automatic exposure control (AEC) control factors in digital radiography systems based on the fine contrast images using coin phantoms. The AEC control factors were targeted at the range of dominent zone, sensitivity, and density. The dominent zone was divided into cases where a single coin was used to cover the field configuration, and cases where seven coins were used to cover the field configuration. The sensitivity was classified into three stages (200, 400, 800) and the density was classified into three stages (2.5, 0, 2.5). Image quality was evaluated by signal to noise ratio (SNR) and contrast to noise ratio (CNR). Then, the automatically exposed tube current was measured. As a result, the X-ray image of seven coins obtained a result value of about 1.2 times higher for SNR and 1.9 times higher for CNR than the X-ray image for one coin. The tube current was also about 1.6 times higher. In conclusion, In AEC, the higher the field configuration and dominent zone are matched and the higher the density, the lower the sensitivity, which increases the tube current and CNR, which increases the image quality. Therefore, it is judged that the appropriate setting of the range of dominent zone, sensitivity, and density of the control, which is the AEC control factor, could improve the fine contrast of images.

• The Journal of the Korean dental association
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• v.55 no.8
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• pp.516-526
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• 2017

Objective: To suggest diagnostic reference levels (DRLs) for dental panoramic radiography in adults and children through the nationwide survey in Korea. Materials and Methods: Two hundred twelve dental institutions on a national basis were visited. The radiographic examination protocols were surveyed and their patient doses at the clinical exposure setting for adult and children (5- and 10-year old) were measured at 244 panoramic radiographic equipment. The measured DAP were analyzed and compared according to age group, the size of hospital, the type of radiographic system, the installation duration of equipment. Results: The mean exposure parameters were 70.1 kV, 9.2 mA, 14.4 second for adult and 66.6 kV, 7.9 mA, 13.8 second for 10-year old child and 65.5 kV, 7.3 mA, 13.7 second for 5-year old child. The mean and third quartile patient DAPs were $138.3mGy\;cm^2$ and $151.0mGy\;cm^2$ for adult, $99.5mGy\;cm^2$ and $104.8mGy\;cm^2$ for 10-year old child and $89.5mGy\;cm^2$ and $95.5mGy\;cm^2$ for 5-year old child. The mean patient dose at the university dental hospital was lower than that at the dental clinic (p<0.05). The mean patient dose of direct digital radiography type was higher than that of film-based type. However, the difference did not show statistically significance. Conclusion: DRLs for dental panoramic radiography in adult, 10- and 5-year old child were suggested to be $151mGy\;cm^2$, $105mGy\;cm^2$, and $96mGy\;cm^2$ in Korea based on this nationwide survey.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.30.1-30.6
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• 2019

We report the surgical endodontic treatment of a maxillary first premolar with a lateral lesion that originated from an accessory canal. Although lesions originating from accessory canals frequently heal with simple conventional endodontic therapy, some lesions may need additional and different treatment. In the present case, conventional root canal retreatment led to incomplete healing with the need for further treatment (i.e., surgery). Surgical endodontic management with a fast-setting calcium silicate cement was performed on the accessory canal using a dental operating microscope. At the patient's 9-month recall visit, the lesion was resolved upon radiography.