• Journal of radiological science and technology
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• v.39 no.1
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• pp.27-33
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• 2016

The use of cardiac angiography (CA) and the interventional procedures is rapidly increasing due to the increase in modern adult diseases. Cardiovascular intervention (CI) is an examination method where radiation is applied to the same area for a long period, and thus may cause skin injury. In this study, we investigate the diagnostic reference level (DRL) of the cardiovascular intervention (CI) carried out by medical institutions and use it as a tool to reduce patient exposure dose. In this study, the DRL was set by acquiring information about the cumulative fluoroscopy time, cumulative fluoroscopy dose-area product (DAP), radiography DAP, cumulative DAP, air kerma, number of video clips, and the total number of images from the cardiac angiography and interventional procedures performed on 147 patients. The DAPs corresponding to the DRL of cardiac angiography(CA) and that of the interventional procedures were shown to be $44.4Gy{\cdot}cm2$ and $298.6Gy{\cdot}cm2$, respectively; the corresponding DRLs of fluoroscopy time were shown to be 191.5s and 1935.3s, respectively. A DRL is not a strict upper bound for radiation exposure. However, the process of setting, enacting, and reviewing the DRLs for the dose by medical institutions will contribute to a reduction in the unnecessary exposure dose of patients.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.1-10
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• 2010

Dental panoramic radiography is an imaging technique which shows the information of teeth, jaws and superficial structures on a single image. In this study, we propose the clinical dose reference for dental panoramic radiography. Dental panoramic radiography is an application which can increase the radiation does of oral cavity. It is very important to study the real condition of management for these panoramic X-ray equipments. Since there was no researches on dental panoramic equipments in domestic and foreign study groups, we measured and analyzed the dose such as effective dose, DAP and DWP of panoramic radiography.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.290-296
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• 2015

The purpose of this study was to derive the proposals and to suggest the exposure dose reduction scheme on pediatric head CT scan by analyzing and comparing CT dose index (CTDI) and the national diagnostic reference levels. From January 2014 to December, 231 children under 10years who were requested a pediatric head CT scan with head injury were examined. Research methods were to research and analyze the general characteristics kVp, mA test coverage $CTDI_{vol}$ and DLP referring to dose reports and electronic medical record (EMR). As a result, 7.4%(17 patients) of the total subjects in $CTDI_{vol}$ showed a national diagnostic reference levels exceeding. For DLP 41.6%(96 patients) in excess was relatively higher than $CTDI_{vol}$. DLP was exceeded more than about 60% that is higher than the CT dose index presented by Korea Food & Drug Administration. it is cause of high DLP that scan range increased more than about 30% wider than the standard test coverage presented in Health Insurance Review & Assessment Service. In conclusion, it is able to significantly lower the dose if it is complied with checking the baseline scan range of pediatric head CT scan and appropriately adjusting the protocol.

• Journal of radiological science and technology
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• v.42 no.6
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• pp.429-434
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• 2019

The gonads are directly affected by radiation exposure during radiography of the pelvis, abdomen, and spine. Exposure of the gonads to radiation can cause genetic mutations and can result in the occurrence of malignant tumors. In this study, we created three types of shielding material shapes for shielding of the ovaries, which are the gonads of female during radiography of the pelvis, and comparative evaluations using shadow shielding methods. The source surface distance(SSD) was 100 cm and the field size was 42 cm × 43 cm. The three types of shielding material shapes(type 1, 2 and 3) were assessed and the entrance surface dose in the ovaries were measured. The thickness of the shielding material was expanded from 0.3 mm to 2.4 mm and after five repetitions, radiation values were measured and mean values were calculated. The mean dose were 3.09 mGy for type 1, 3.54 mGy for type 2, and 3.19 mGy for type 3, indicating that the measurements were the lowest for type 1. When an additional filter of 0.2 Cu + 1 Al was used, the dose were 3.72 mGy for type 1, 5.43 mGy for type 2, and 4.05 mGy for type 3, indicating that the measurements were the lowest for type 1. The results show that, even if the shielding material is not thick, in other words, even with a thickness of 2.94 mGy for the SN 3(0.9 mm) of type 1, shielding can be achieved, with a patient dose lower than the diagnostic reference level(3.42 mGy). Additionally, among the three types of shielding material, the type 1 appeared to be the most appropriate shielding material. It is thought that the use of shielding material could reduce the risk factors for stochastic effects or critical effects of ionizing radiation during pelvic or lumbar radiography.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.351-357
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• 2018

During radiation therapy, the patient is exposed to secondary radiation by scattered and leakage radiation. For the diagnostic radiation, guidelines for reducing the patient's exposure as the diagnostic reference level are provided. However, in the case of therapeutic radiation, even though the radiation dose by the secondary radiation is considerable, the prescription dose is not limited because of the reason of the therapeutic efficiency. The purpose of this study was to evaluate the secondary radiation that the patient could be received at the peripheral tissue during the radiotherapy using the linear accelerator with the radiophotoluminescent glass dosimeter. In addition, we measured the degree of saturation of the luminescent amount according to the build-up characteristic of the radiophotoluminescent glass dosimeter. As a result of carrying out this study, the exposure dose decreased drastically farther away from the treatment field. When the head was irradiated with 1 Gy, the neck could be exposed to 18.45 mGy. When the same dose was irradiated at the neck, 15.55 mGy of the head and irradiated at the chest, 14.26 mGy of the neck and irradiated at the pelvis, 1.14 mGy of the chest were exposed separately. The degree of saturation of the luminescent intensity could be overestimated by 1.8 ~ 4.8% depending on time interval for 3 days.