• 대한방사선기술학회지:방사선기술과학
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• 제37권3호
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• pp.195-201
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• 2014

본 연구에서는 구내 촬영시 방사선작업종사자와 X선관 사이 거리의 증가에 따라 방사선작업종사자의 안면부 피폭선량 감소의 변화를 측정하고자 하였다. 우선 인체조직과 유사한 안면부 Phantom을 제작하였다. 구내 촬영 장치를 이용하여 촬영조건을 성인 상악 대구치부 노출조건 (60kVp, 10mA. 50msec)과 소아 상악 대구치부 노출조건 (60kVp, 10mA, 20msec)으로 설정 하고 방사선작업종사의 안면부의 위치에 Chamber를 고정시켰다. X선 관구와 Phantom을 Chamber로 부터 10cm, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm 위치시킨 후 각 검사조건으로 Phantom을 20회 조사한 후 평균 산란선량을 측정 하였다. 연구 결과 성인 조건으로 조사한 후 감소율은 10cm에서 조사한 산란선량을 기준으로 하였을 때 40cm 에서는 감소율이 7.43%로 약 92.6%가 감소가 되었다. 또한 소아 조건으로 조사한 후 감소율은 10 cm에서 조사한 산란선량을 기준으로 하였을 때 40 cm 에서는 감소율이 2.58 %로 약 97.6%가 감소가 되었다. 결론적으로 치과 방사선 검사 시 방사선 피폭에 대한 방호가 필요할 것으로 사료된다.

• 턱관절균형의학회지
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• 제6권1호
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• pp.24-26
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• 2016

경추부 근긴장 이상증에 대해 턱관절 자세균형 개념에 따라 구강내 균형장치를 활용한 자세훈련법 등의 치료로 긍정적인 호전을 관찰했다. 증례 보고이기는 하지만 턱관절 자세균형을 활용한 치료법에서 긍정적인 치료효과가 이어지고 있어서 앞으로 더욱 체계적인 관찰과 연구가 필요할 것으로 사료된다.

• Imaging Science in Dentistry
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• 제44권3호
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• pp.253-254
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• 2014

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.799-804
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• 2016

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

• Imaging Science in Dentistry
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• 제41권3호
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• pp.115-121
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• 2011

Purpose : This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods : A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results : This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion : This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin.

• 한국방사선학회논문지
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• 제15권4호
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• pp.491-498
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• 2021

본 연구에서는 국가에서 권고하고 있는 구강 내 촬영의 진단참고 준위 설정에 사용된 조건을 조사하여 PCXMC v2.0 프로그램을 이용하여 유효선량을 측정하고 Al 부가 필터의 효과를 확인하였다. 구내 촬영에서 11개 측정 장기들 중에서 대부분 연구대상에서 구강 점막에서 가장 큰 유효선량이 계산되었다. Al 부가 필터의 효과는 1mm보다 2mm에서 탁월한 방사선 피폭선량 저감효과를 보였다. 소아 5세의 경우 성인에 비하여 방사선 감수성이 크기 때문에 전반적으로 유효선량이 11개의 장기들 모두에서 높게 계산되었다. 그리고 구강 내 촬영 시 부가 필터 사용에 따른 영상 품질 평가를 실시한 결과 SNR 및 CNR의 변화가 부가 필터를 사용하기 전과 별다른 차이가 없었다. 본 연구를 바탕으로 구강 내 촬영 시 부가 필터 설정을 권고할 수 있을 것이라 사료 된다.

• 한국방사선학회논문지
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• 제17권4호
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• pp.515-521
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• 2023

치과 구내 촬영 시 사용하는 관전류 및 시간에 따라 환자가 받는 피폭선량은 달라진다. 영상의 질을 위해서는 많은 양의 관전류가 필요하지만, 환자에게 부여되는 방사선량은 그만큼 높아진다. 이에 본 연구에서는 시뮬레이션을 통한 치과 구내 촬영 시 사용하는 관전류에 따른 영상의 질 평가를 통해 영상의 질을 확보하면서 환자가 받는 피폭선량은 감소시킬 수 있는 최적의 관전류 양을 산출하였다. 치과 구내 촬영의 진단참고수준 가이드라인에 제시된 평균 관전류와 시간 및 관전압을 기본 촬영 조건으로 사용하고, 관전류만 변화시켰을 때 영상을 획득한 후 기본 영상과의 영상의 질 비교·분석을 통해 최적의 관전류 양을 산출하였다. 기본 조건은 63 kV, 6 mA, 0.29 s로 하고 관전류를 0.1, 0.5, 1, 2, 3, 4, 5 mA로 변경시켜 영상을 획득하였다. 획득한 영상은 ICY 프로그램을 사용하여 6 mA의 조건으로 촬영한 영상과 구조적 유사지수를 평가하였다. 그 결과 0.5 mA의 관전류 조건에서도 6 mA의 영상과 구조적 유사지수가 높은 것으로 평가되었다. 이러한 결과를 바탕으로 치과 구내 촬영 시 6 mA가 아닌 0.5 mA로 촬영한다면 환자에게 부여되는 피폭선량을 매우 감소시킬 수 있을 것으로 판단된다.

• Imaging Science in Dentistry
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• 제47권4호
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• pp.233-239
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• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients

• 한국치위생학회지
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• 제16권2호
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• pp.205-214
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• 2016

Objectives: The purpose of the study is to investigate the current status and radiographic safety management in Korea. Methods: A self-reported questionnaire was completed by 200 dental hygienists in Jeonbuk province from September 1, 2014 and October 31, 2014. The questionnaire consisted of general characteristics of the subjects, radiation knowledge, radiation safety management, and radiation exposure anxiety. Data were analyzed using SPSS 18.0 program. Results: Duration of clinical experience(r=0.142) and number of daily radiation shot(r=0.145) showed a positive correlation to radiation safety management, and a nrgative correlation to use of intraoral films and digital devices(r=-0.587). A logistic regression analysis was performed in order to evaluate the influence on radiography knowledge. The results showed that the factors had significant influences on the age group over 41 years old(OR 7.25; 95% CI 1.30-40.43) and those who took a position above team leader(OR 0.23; 95% CI 0.59-0.90). Conclusions: It is very important to have the safety management toward dental intraoral imaging and radiograpgic shot in the dental hygienists. Continuous efforts should be emphasized on radiographic safety management and behavior.

• Imaging Science in Dentistry
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• 제34권3호
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• pp.117-122
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• 2004

Purpose : To determine the proper image compression method and ratio without image quality degradation in intraoral digital radiographic images, comparing the discrete cosine transform (DCT)-based JPEG with the wavelet-based JPEG 2000 algorithm. Materials and Methods : Thirty extracted sound teeth and thirty extracted teeth with occlusal caries were used for this study. Twenty plaster blocks were made with three teeth each. They were radiographically exposed using CDR sensors (Schick Inc., Long Island, USA). Digital images were compressed to JPEG format, using Adobe Photoshop v.7.0 and JPEG 2000 format using Jasper program with compression ratios of 5 : 1,9 : 1, 14 : 1,28 : 1 each. To evaluate the lesion detectability, receiver operating characteristic (ROC) analysis was performed by the three oral and maxillofacial radiologists. To evaluate the image quality, all the compressed images were assessed subjectively using 5 grades, in comparison to the original uncompressed images. Results: Compressed images up to compression ratio of 14 : 1 in JPEG and 28 : 1 in JPEG 2000 showed nearly the same the lesion detectability as the original images. In the subjective assessment of image quality, images up to compression ratio of 9 : 1 in JPEG and 14 : 1 in JPEG 2000 showed minute mean paired differences from the original Images. Conclusion : The results showed that the clinically acceptable compression ratios were up to 9 : 1 for JPEG and 14 : 1 for JPEG 2000. The wavelet-based JPEG 2000 is a better compression method, comparing to DCT-based JPEG for intraoral digital radiographic images.