• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.1
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• pp.31-35
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• 1994

전남대학교 치과진료처에 내원한 환자의 구내방사선사진중 1단계 (Cl: 30개 병소)또는 2단계(C2: 213.8병소)의 인접면 치아우식을 가진 방사선사진 168장을 연구대상으로 하였다. 이들 방사선사진은 코닥사의 Ektaspeed(E group) 필름을 사용하여 평행촬영법으로 촬영하였다. 168장의 방사선사진에 대하여 1단계 및 2단계 치아우식증을 4명의 구강악안면방사선학을 전공한 치과의사들이 같이 판독하여 그 결과를 기록하였다. 또한 168장의 방사선사진을 필름-비디오 변환장치를 이용하여 디지털 영상으로 전환하였다. 이때 486 DX PC에 PCVision과 frame grabber를 이용하였다. 각각의 구내방사선사 진영상은 17"크기의 1280×768픽셀의 해상도를 갖는 모니터상에서 256단계 흑화도를 갖는 700×480픽셀로 제시되었다. 모니터상에서의 치아우식 판독 결과를 구내방사선사진 판독 결과와 비교하였다. 그 결과 sensitivity는 0.98이었다. 1단계 치아우식은 0.87, 2단계 치아우식 은 1.00의 sensitivity를 나타내었다.

• Proceedings of the KSLP Conference
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• 1995.11a
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• pp.181-184
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• 1995

일반적으로 의료상에서 방사선 사진 상으로부터 병소 부위를 찾아내어 질병의 유무 및 진단을 해왔으나 명확하지 못한 방사선 사진 자체의 문제점들과 사진 현상시의 문제점들로 인하여 진단의 혼란을 초월할 수 있다. 또한 오래 전부터 컴퓨터의 발달로 인하여 방사선 사진을 입력, 진단하려는 움직임도 있었으나 많은 노력에도 불구하고 입력시키려는 사진이 잡음이 많고 대비가 상당히 안 좋은 상태이므로, 이로 인한 해상도의 문제점으로 이를 기피하고 현상되어 나온 사진자체로 진단을 하려고 하였다. (중략)

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.251-261
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• 2005

Enlargement is an inherent property of X-rays which occurs when straight hues diverse from small a focal spot. The purpose of the present study was to evaluate the validity of the correction of gonial angle width enlarged on frontal cephalogram, using frontal and lateral cephalograms taken orthogonally from each other. In 40 adult individuals, frontal and lateral cephalograms were taken at a $90^{\circ}$ angle using the Head Posture Aligner. The angle width was measured on the frontal cephalogram and subsequently. the corrected angle width was calculated using the magnification rate of two cephalograms. Measured and corrected angle widths were compared with the measurement from the 3D CT image. The measurement or the frontal cephalogram showed a 9.10mm of enlargement on average ranging from 7.92 to 11.31mm. Corrected angle width measurement showed a 0.14mm difference with the 3D CT image measurement, which was not statistically significant. The results of the study indicate that actual au91e width can be approached through calculation using frontal and lateral cephalograms taken orthogonally with the help of the Head Posture Aligner The study also showed that the magnitude of correction error did not show a significant correlation with the amount of menton deviation, and it suggests that the present correction method is valid even in individuals with severe facial asymmetry.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.323-332
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• 1993

저자는 1988년 6월 1일부터 1993년 6월 30일까지 서울대학교병원 치과진료부에 내원하여, 병리조직학적으로 확인된 구강악안면부 악성종양환자 35명의 방사선사진 소견과 자기공명영상 소견을 비교하여 다음과 같은 결론을 얻었다. 1. 일반적인 방사선사진소견으로는 미만성의 골파괴가 15례 (42.9%), 연조직종괴의 음영이 7례 (20,0%), 부유치를 보인 경우가 3례 (8.6%), 골경화가 2례 (51.7%)로 나타났다. 2. 자기공명영상 소견은 연조직종괴가 23례 (65.7%), 골수침범이 12례(34.5%), 피질골 파괴가 14례(40.0%), 정상피질골에 골수침범이 1례 (2.9%), 지방층소실이 19례(54.3%), 림파절전이가 8례 (22.9%), 조영증강이 15례 (42.9%), 골증식이 1례 (2.9%)였다. 3. 구강악안면부의 악성종양환자에 있어서, 방사선사진에서 관찰하기 힘들었던, 종양의 구강저, 저작근, 부인두강, 사골동, 측두하와, 악하선, 비강 등 인접조직으로의 침범여부 및 골파괴 정도와 림파절전이를 평가하는 데 자기공명영상은 도움을 주었다. 4. 정진율은, 방사선사진에서 35례중 16례로 45.7%였고, 자기공명영상에서는 35례중 27례로 77.1%로 자기공명영상의 정진율이 더 높았으나, 일반적인 방사선사진이 자기공명영상보다 더 우세한 경우도 2례 있었다.

• The korean journal of orthodontics
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• v.19 no.2
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• pp.165-175
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• 1989

In evaluation of some area within the craniofacial complex posteroanterior cephalogram together with lateral cephalogram is used for assessment of the exact existence and posture by grasping 3-dimensional concept. The usages of posteroanterior cephalogram in orthodontics are following; 1. The use during diagnosis and treatment planning 1) Assessment of the area and amount of facial asymmetry. 2) Assessment of therapeutic position for diagnosis and treatment 2. The Assessment of success in orthodontic mechanics If we use posteroanterior cephalogram together with lateral cephalogram adequately and simultaneously we can establish the exact diagnosis and appropriate treatment planning.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.74-83
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• 2006

Analysis of lateral cephalometric radiograph (cephalogram) has been used routinely to evaluate skeletal and dental relationships, but analysis of the lateral facial photograph has not been used frequently for evaluation of skeletal relationships. As concerns about harm of X-ray irradiation increases, this study was planned to evaluate the possibility of substituting analysis of the lateral cephalogram with analysis of the lateral facial photograph by comparing these two analyses. According to the ANB values from cephalometric analysis, subjects were divided into three groups: Class I malocclusion group (n=32). Class II malocclusion group (n=32), and Class III malocclusion group (n=31). After measurements of angles indicating horizontal and vertical relationships of the maxilla and mandible on the lateral cephalograms and photographs, differences between Class I, II and III groups were evaluated. To evaluate the similarity between two similar values in the cephalograms and photographs, t-test using standardized variable Z and correlation analysis were performed in the Class I malocclusion group. The results showed that 1) SnN'Pg' on the photograph can be used to evaluate the antero-posterior relationship of the maxilla and mandible (ANB), 2) N'-Sn/Sn-Pg' on the photograph can be used to evaluate facial convexity (NA/APg), 3) Sn-Tra-Me' on the photograph can be used as a measurement similar to FMA. In conclusion, partly substituting lateral cephalogram analysis with lateral facial photograph analysis was possible in the evaluation of the maxilla and mandible.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.321-326
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• 1998

본 연구에서는 환자와 한의사, 방사선 전문의 간에 초고속 통신망을 이용하여 원격으로 환자의 질환 상태를 파악하고 이에 따른 처방전을 내릴 수 있도록 하는 한방 원격 검진 시스템에서 환자의 X-ray 사진, CT 사진 등의 방사선 이미지들을 DICOM 프로토콜에 의거하여 저장하고 검색할 수 있도록 해주는 시스템을 구현하였다. 본 연구에서는 이미지 처리 및 관리 모듈을 Java 언어를 이용하여 구현함으로써 방사선 전문의와 한의사들이 컴퓨터의 기종에 관계없이 웹브러우저를 사용하여 환자의 X-ray나 CT 등의 방사선 사진을 살펴볼 수 있도록 하였다.

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.18-22
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• 2012

This study was performed to evaluate the sensitivity of conventional film-screen radiography (CFSR) and direct digital radiography (DDR) for detection of various amounts of free peritoneal fluid. Ten adult male healthy beagles were used in this study. Radiographic examinations were performed in the right lateral and ventrodorsal positions. Fluid was injected in increments of 2.0 ml/kg of body weight up to 20.0 ml/kg of body weight. The images of CFSR and DDR were evaluated by two veterinary radiologists for evidence of abdominal fluid without knowledge of injected fluid volume. Data were evaluated by using the receiver operation curve (ROC) analysis and the area under the curve (AUC). There was no significant difference in detection of peritoneal fluid between DDR and CFSR in the ROC analysis. The accuracy of CFSR (0.805) was relatively higher than that of DDR (0.733), based on the ROC analysis and AUC. AUC of CFSR was higher in most injection doses. These results suggest that CFSR is more accurate than DDR for the detecting peritoneal fluid. Therefore, for situation in which digital radiographs are equivocal or small amount of fluid is suspected, other imaging modalities, such as ultrasonography would be helpful for determining the presence of fluids.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.543-552
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• 2000

The purposes of this study were to evaluate the reproducibility of posteroanterior(PA) cephalograms obtained by two methods, the Head Posture Aligner(HPA) method in natural head posture and the conventional method(operator-guided method), and to compare the vertical rotational differences of the head Posture between lateral and PA cephalograms according to the method. The sample was consisted of 30 adults. At first day, a PA cephalogram and a lateral cephalogram were obtained from each subject by two methods to investigate the difference of vertical rotational posture between lateral and PA cephalograms. Two weeks later, another PA cephalogram was obtained using each method to evaluate the reproducibility of head posture. Five height measurements and nine width measurements were used in the paired t-test to compare the reproducibility of the PA cephalometric measurements between two methods. The differences of vertical rotational posture between lateral and PA cephalograms were calculated from a computer program and compared according to the method used, and following results were obtained. 1. Height measurements obtained by operator-guided method showed significant differences according to the time interval and revealed low reproducibility. 2. Height measurements obtained by HPA method did not show significant differences according to the time interval and presented high reproducibility. 3. In the comparison of width measurement, two methods did not show distinct differences in reproducibility. 4. The difference of vertical rotational posture between lateral and PA cephalograms showed $0.8^{\circ}$ in the HPA method, more less than $2.5^{\circ}$ in the operator-guided method. The results of the present study suggest that the HPA may be helpful in the PA cephalometric radiography in terms of reproducibility.

• The korean journal of orthodontics
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• v.32 no.2 s.91
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• pp.79-89
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• 2002

The purpose of this study is to evaluate the reproducibility and errors in landmark identification of conventional lateral cephalometric radiography and digital lateral cephalometric radiography. Fifteen conventional lateral cephalometric radiographs and fifteen digital lateral cephalometric radiographs were selected in adults with no considerations on sex and craniofacial forms. Each landmark was identified and expressed as the coordinate (x, y). The landmarks were classified into 3 groups. The landmarks of the first identification was T1, identification after one week was T2, and identification after one month was T3. The mean and standard deviation of identification errors between replicates were calculated according to the x and y coordinates. The errors between first identification and second identification were expressed as T2-T1(x), T2-T1(y) and those between first identification and third identification were expressed as T3-T1(x), T2-T1(y). Each was divided into conventional lateral cephalometric radiography and digital lateral cephalometric radiography. The independent t- test was used for statistical analysis of identification errors for the evaluation of reproducibility. The results of this study were as follows ; 1. Generally, the mean and standard deviation of landmark identification errors in digital lateral cephalometric radiography was smaller than those of conventional lateral cephalometric radiography. 2. Only a few landmarks showed statistically significant difference in identification error between conventional lateral cephalometric radiography and digital lateral cephalometric radiography. 3. The enhancement of image quality didn't guarantee decrease in landmark identification error and didn't affect tendency of landmark identification error.