• Imaging Science in Dentistry
• /
• v.48 no.2
• /
• pp.121-125
• /
• 2018

Purpose: Detecting laryngeal cartilages (triticeous and thyroid cartilages) on panoramic radiographs is important because they may be confused with carotid artery calcifications in the bifurcation region, which are a risk factor for stroke. This study assessed the efficiency of panoramic radiography in the diagnosis of calcified laryngeal cartilages using cone-beam computed tomography (CBCT) as the reference standard. Materials and Methods: A total of 312 regions(142 bilateral, 10 left, 18 right) in 170 patients(140 males, 30 females) were examined. Panoramic radiographs were examined by an oral and maxillofacial radiologist with 11 years of experience. CBCT scans were reviewed by 2 other oral and maxillofacial radiologists. The kappa coefficient(${\kappa}$) was calculated to determine the level of intra-observer agreement and to determine the level of agreement between the 2 methods. Diagnostic indicators(sensitivity, specificity, accuracy, and false positive and false negative rates) were also calculated. P values <.05 were considered to indicate statistical significance. Results: Eighty-two images were re-examined to determine the intra-observer agreement level, and the kappa coefficient was calculated as 0.709 (P<.05). Statistically significant and acceptable agreement was found between the panoramic and CBCT images (${\kappa}=0.684$ and P<.05). The sensitivity, specificity, diagnostic accuracy rate, the false positive rate, and the false negative rate of the panoramic radiographs were 85.4%, 83.5%, 84.6%, 16.5%, and 14.6%, respectively. Conclusion: In most cases, calcified laryngeal cartilages could be diagnosed on panoramic radiographs. However, due to variation in the calcifications, diagnosis may be difficult.

• Journal of the Korean Society of Radiology
• /
• v.10 no.3
• /
• pp.161-169
• /
• 2016

In this study, the proposal to seek ways to reduce the amount of radiation is drawn by comparing and analyzing CT Dose Index(CTDI) on the pediatric head CT which was performed at the busan regional hospitals, to the national diagnostic reference levels. As a result, it was appeared to exceed the amount of the dose recommendation in order of hospital, general hospital and senior general hospital in the hospital-specific classification and from 2 to 5 year, from 1 month to 1 year and from 6 to 10 year in the age-specific classification. In addition, the amount of the dose recommendation was exceed in order of helical, axial and volume in the scan-specific classification. As the results of the scan range reset to match the diagnostic reference level, the dose reduction showed 11.68%, 15.79% and 20.66% in senior general hospital, general hospital and hospital respectively. In the results of analysing patient average scan ranges which does not deviate from the guideline of patient dose recommendation, there was age of 1 month to 1 year, 2 to 5 year and 6 to 10 year of $03.2{\pm}11.8mm$, $110.5{\pm}14.5mm$, and $117.8{\pm}17.2mm$ respectively.

• Journal of the Korean Society for Railway
• /
• v.9 no.4 s.35
• /
• pp.357-361
• /
• 2006

This paper dealt with the performance evaluation and the diagnostic techniques of lightning arresters for DC electric traction vehicle. Field Measurements on the protective operation of lightning arresters against surge currents were carried out on running vehicles to acquire the data necessary for the diagnosis. The frequency and the magnitude of surge events were analyzed. Surge currents of $1\sim3$ times were recorded in one running service route and their magnitudes were ranges of $150A\sim2kA$. Also, an acceleration experiment on a lightning arrester by the standard lightning impulse current of 8/20 us and 5 kA was performed to know the aging characteristics. After the surge current application of 3,000 times, the reference voltage decreased by 4.5 %, and the leakage current was below 10 uA at the continuous operating voltage and about 50 uA at the rated voltage. From the experimental results, we propose a decision level of leakage current for the arrester used in this paper and designed an arrester tester which analyzes arrester condition by the magnitude of leakage current.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.3
• /
• pp.323-330
• /
• 2009

Nontuberculous mycobacteria (NTM) are a major cause of opportunistic infections in immunocompromised patients, making the reliable and rapid identification of NTM to the species level very important for the treatment of such patients. Therefore, this study evaluated the usefulness of the novel target genes tuf and tmRNA for the identification of NTM to the species level, using a PCRrestriction fragment length polymorphism analysis (PRA). A total of 44 reference strains and 17 clinical isolates of the genus Mycobacterium were used. The 741 bp or 744 bp tuf genes were amplified, restricted with two restriction enzymes (HaeIII/MboI), and sequenced. The tuf gene-PRA patterns were compared with those for the tmRNA (AvaII), hsp65 (HaeIII/HphI), rpoB (MspI/HaeIII), and 16S rRNA (HaeIII) genes. For the reference strains, the tuf gene-PRA yielded 43 HaeIII patterns, of which 35 (81.4%) showed unique patterns on the species level, whereas the tmRNA, hsp65, rpoB, and 16S rRNA-PRAs only showed 10 (23.3%), 32 (74.4%), 19 (44.2%), and 3 (7%) unique patterns after single digestion, respectively. The tuf gene-PRA produced a clear distinction between closely related NTM species, such as M. abscessus (557-84-58) and M. chelonae (477-84-80-58), and M. kansasii (141-136-80-63-58-54-51) and M. gastri (141-136-117-80-58-51). No difference was observed between the tuf-PRA patterns for the reference strains and clinical isolates. Thus, a diagnostic algorithm using a tuf gene-targeting PRA is a promising tool with more advantages than the previously used hsp65, rpoB, and 16S rRNA genes for the identification of NTM to the species level.

• Journal of the Korean Society of Radiology
• /
• v.16 no.7
• /
• pp.897-904
• /
• 2022

The purpose of this study is to compare the difference in dose and image quality when applying the diagnostic reference level (DRL) test conditions for head radiography in a digital radiation environment and the test conditions currently applied in clinical practice. I would like to review the conditions of radiographic examination. In this study, the head model phantom was targeted, and the investigation conditions were divided into clinical conditions (Clinic), DRL value (DRL₇₅), and DRL average value (DRL_mean). For dose, Enterance surface dose (ESD) was measured, and for image quality, signal-to-noise ratio and contrast-to-noise ratio were measured and analyzed for comparison. The average values of skull anterior posterior(AP) ESD according to the changes in test conditions were Clinic 1214.03±4.21 µGy, DRL₇₅ 3017.83±8.14 µGy, DRL_mean 2283.50±7.09 µGy, and skull lateral (Lat). The average value of ESD was statistically significant with Clinic 762.79±3.54 µGy, DRL₇₅ 2168.57±10.83 µGy, and DRL_mean 1654.43±6.48 µGy (p<0.01). The average values of SNR and CNR measured in the orbital, maxillary sinus, frontal sinus, and sella turcica were statistically significant (p<0.01). As a result of this study, compared to DRL, the conditions used in clinical practice showed lower dose levels of about 58% for AP and about 70% for Lat., and there was no qualitative difference in terms of image quality. Through this study, it is necessary to consider a new diagnostic reference level suitable for the digital radiation environment, and it is considered that the dose should be reduced accordingly.

• Journal of Korean Society on Water Environment
• /
• v.33 no.5
• /
• pp.511-524
• /
• 2017

This study was carried out for the purpose of creating a restoration plan to improve the ecological quality of the Changwon and Nam streams. Based upon the results of comprehensive diagnostic assessment, restoration priority was given to the upstream reach, where conservation status is relatively superior. Restoration level was usually determined to practice active restoration as conservation, and the states of both Changwon and Nam streams were not so good. Restoration plans, by reach, were classified into "upstream", "midstream", and "downstream" were suggested in both terms of horizontal section frame and vegetation-based on the result of diagnostic assessment and the reference information. "Upstream", "mid-stream" and the "downstream" of Changwon and Nam streams were classified into "small-gravel- mountainous", "small-sand-plain", and "small-clay-plain streams" respectively (based on scale, and substrate and slope of river bed). The spatial arrangement of vegetation was laid out in diagram form by reflecting micro-topography and the water level of the horizontal section of river. Information regarding species composition was recommended as dominant species, which appear frequently in three vegetation zones composed of herbaceous plants, shrubs and trees and sub-tree- dominated zones divided by reflecting disturbance regime, depending on position on the horizontal section of river. Moreover, there have been prepared not only plans to improve the terrestrial ecosystems around the streams but also plans to create ecological networks, which can serve to improve the ecologic quality of the whole regional environment by serving to connect streams and terrestrial ecosystems, a process probably necessary and definitely recommended to realize true (genuine) restoration. Plans for ecological parks and networks were prepared by mimicking the species composition of Alnus japanica community, Zelkova serrata community, Carpinus laxiflora community, Quercus aliena community, and Q. serrata community.

• Journal of radiological science and technology
• /
• v.32 no.4
• /
• pp.401-410
• /
• 2009

Purpose : Pelvis and lumbar spine radiography, among various types of diagnostic radiography, include gonads of the human body and give patients high radiation dose. Nevertheless, diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography has not yet been established in Korea. Therefore, the radiation dose that patients receive from pelvis and lumbar radiography is measured and the diagnostic reference level on patient radiation dose for the optimization of radiation protection of patients in pelvis and lumbar spine radiography was established. Methods : The conditions and diagnostic imaging information acquired during the time of the postero-anterior view of the pelvis and the postero-anterior and lateral view of the lumbar spine at 125 medical institutions throughout Korea are collected for analysis and the entrance surface dose received by patients is measured using a glass dosimeter. The diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography to be recommended to the medical institutes is arranged by establishing the dose from the patient radiation dose that corresponds to the 3rd quartile values as the appropriate diagnostic reference level for patient radiation dose. Results : According to the results of the assessment of diagnostic imaging information acquired from pelvis and lumbar spine radiography and the measurement of patient entrance surface dose taken at the 125 medical institutes throughout Korea, the tube voltage ranged between 60~97 kVp, with the average use being 75 kVp, and the tube current ranged between 8~123 mAs, with the average use being 30 mAs. In the posteroanterior and lateral views of lumbar spine radiography, the tube voltage of each view ranged between 65~100 kVp (average use: 78 kVp) and 70~109 kVp (average use: 87 kVp), respectively, and the tube current of each view ranged between 10~100 mAs(average use: 35 mAs) and between 8.9~300 mAs(average use: 64 mAs), respectively. The measurements of entrance surface dose that patients receive during the pelvis and lumbar spine radiography show the following results: in the posteroanterior view of pelvis radiography, the minimum value is 0.59 mGy, the maximum value is 12.69 mGy and the average value is 2.88 mGy with the 1st quartile value being 1.91 mGy, the median being 0.59 mGy, and the 3rd quartile value being 3.43 mGy. Also, in the posteroanterior view of lumbar spine radiography, the minimum value is 0.64 mGy, the maximum value is 23.84 mGy, and the average value is 3.68 mGy with the 1st quartile value being 2.41 mGy, the median being 3.40 mGy, and the 3rd quartile value being 4.08 mGy. In the lateral view of lumbar spine radiography, the minimum value is 1.90 mGy, the maximum value is 45.42 mGy, and the average value is 10.08 mGy with the 1st quartile value being 6.03 mGy, the median being 9.09 mGy and the 3rd quartile value being 12.65 mGy. Conclusions : The diagnostic reference levels for patient radiation dose to be recommended to the medical institutes in Korea is 3.42 mGy for the posteroanterior view of pelvis radiography, 4.08 mGy for the posteroanterior view of lumbar spine radiography, and 12.65 mGy for the lateral view of lumbar spine radiography. Such values are all lower than the values recommended by 6 international organizations including World Health Organization, where the recommended values are 10 mGy for the posteroanterior view of pelvis radiography, 10 mGy for the posteroanterior view of lumbar spine radiography and 30 mGy for the lateral view of lumbar spine radiography.

• Journal of Korean Society of Rural Planning
• /
• v.27 no.1
• /
• pp.9-20
• /
• 2021

In order to develop practical indicator that can diagnose the regional conditions and characteristics of fishing villages, this study reviewed domestic and foreign researches and selected the diagnostic indicator of fishing villages by spatial unit. The major categories are divided into population and society, economic conditions, and living conditions. The middle categories consists of population, household, industry, tourism, settlement, environment, safety, health and welfare, education, and culture and leisure. The indicator were selected with reference to the existence of statistical data officially provided according to the spatial range(Si/Gun, eup/myeon, village). Based on the selected indicator, the test evaluation was conducted in Jindo-gun, Jeollanam-do by applying data that can be obtained from KOSIS and web GIS. It is judged that the diagnostic indicator developed through this research can be used in various ways from the planning stage to the implementation stage of the regional development project, such as grasping the current conditions, setting improvement targets, promotion and evaluation/monitoring of the project. In addition, it is expected that it will be possible to carry out regional diagnosis for each spatial unit and to plan and implement regional development projects by giving priority to areas where the level of each department is insufficient.

• Progress in Medical Physics
• /
• v.22 no.4
• /
• pp.163-171
• /
• 2011

The purpose of this study was to investigate the effect of various technical parameters for the dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE) including the scatter radiation from the object, the blur caused by the focal spot, geometric magnification and detector characteristics. For the tube voltages ranging from 40 to 90 kVp in 10 kVp increments at the FDD of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at the same effective dose. The results showed that the eDQE was largest at 60 kVp when compares the eDQE at different tube voltage. Especially, the eDQE was considerably higher without the use of an anti-scatter grid on equivalent effective dose. This indicates that the reducing the scatter radiation did not compensate for the loss of absorbed effective photons in the grid. When the grid is not used the eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF). However, most of major hospitals in Korea employed a short FDD of 100 cm with an anti-scatter grid for the chest radiological examination of a 15 month old infant. As a result, the entrance surface air kerma (ESAK) values for the hospitals of this survey exceeded the Korean DRL (diagnostic reference level) of $100{\mu}Gy$. Therefore, appropriate technical parameters should be established to perform pediatric chest examinations on children of different ages. The results of this study may serve as a baseline to establish detailed reference level of pediatric dose for different ages.

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