• Imaging Science in Dentistry
• /
• v.36 no.2
• /
• pp.89-94
• /
• 2006

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

• Imaging Science in Dentistry
• /
• v.38 no.3
• /
• pp.169-176
• /
• 2008

Purpose : To assess the diagnostic accuracy and value in an imaging technique field through the comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Materials and Methods : Participants consisted of 100 patients offered the images through cone beam computed tomography and panoramic radiography. PSR-$9000^{TM}$ Dental CT system (Asahi Roentgen Ind. Co., Ltd, Japan) was used as the unit of cone beam computed tomography. CE-II (Asahi Roentgen Ind. Co., Ltd, Japan) and Pro Max (Planmeca Oy, Finland) were used as the unit of panoramic radiography. The images obtained through panoramic radiography were classified into 3 types according to the distance between mandibular canal and root of mandibular third molar. And they were classified into 4 types according to the proximity of radiographic feature. The images obtained through cone beam computed tomography based on the classification above were classified into 4 types according to the location between the mandibular canal and the root and were analyzed. And they were classified into buccal, inferior, lingual, and between roots, according to the location between mandibular canal and root. The data were statistically analyzed and estimated by $X^2$-test. Results : 1. There was no statistical significance according to 3 types (type I, type II, type III) through CBCT. 2. The results of 4 types (type A, type B, type C, type D) through CBCT were as high prevalence of CBCT 1 in type A, CBCT 2 in type B, CBCT 3 in type C, and CBCT1 in type D and those of which showed statistical significance (P value=0.03). 3. The results according to location between mandibular canal and root through CBCT recorded each 49, 25, 17, 9 as buccal, inferior, lingual, between roots. Conclusion : When estimating the mandibular canal and the roots through the panoramic radiography, it could be difficult to drive the views of which this estimation was considerable. Thus it is required to have an accurate diagnostic approaching through CBCT that could estimate the location between mandibular canal and roots.

• Journal of Radiation Protection and Research
• /
• v.37 no.2
• /
• pp.103-107
• /
• 2012

This paper analyzes changes in the external radiation dose rate of PET-CT test patients as a part of providing basic materials for reduction of radiation exposure to PET-CT test patients. In theory the measurement of external radiation dose rate of PET-CT test patients shows that the further the distance from the patient injected with radioactive pharmaceutical and a longer time elapsement from the injection leads to a smaller amount of radiation. Particularly, the amount of radiation marked the highest in the chest was at 4.17 minutes immediately after the intravenous injection and in the head after 77.47 minutes after urination in advance to the PET-CT test. As in the generalized information, it is desired to keep distance between the patient and caretakers or professionals to reduce the amount of radiation exposure from PET-CT test patients and to resume contact the patient after the time when the radiation has reduced. If contact is unavoidable, it is desired to keep at least 200cm from the patient. In addition, the amount of radiation reached the highest in the chest at first and then in the head from 77 minutes after injection. Accordingly, it would be helpful in achieving the optimization if contact is made based on the patient's physical characteristics. This study is significant as it measures changes in radiation the dose rate by; distance from the PET-CT test patient, time elapsed, and specific parts of body. Further studies based on the findings in this paper are required to analyze changes in radiation dose rate in accordance with individual characteristics unique to PET-CT patients and to utilize the results to reduce the amount of radiation patient, caretakers and professions are exposed.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.1
• /
• pp.61-71
• /
• 2009

Anchorage control is important in orthodontic treatment. Recently miniscrew is widly used as maximum anchorage in orthodontic treatment, and then it is important to install miniscrew safely without damaging adjacent anatomic structure. In a view of Miniscrew's stability, maxilla is unfavorable than mandible, and moreover maxillary soft buccal bone has disadvantage on stability. so palatal area comes into notice for installation area. We measured distance between palatal roots and bone thickness at midpalatal area using 3D computed tomography, and have found following results. 1. On the comparison of distance between palatal roots, the distance between 2nd premolar and 1st molar was significantly longest and the distance between premolars was significantly shortest. 2. Going toward lateral area from midpalatal suture and posterior area from zero point, bone thickness significantly became shorter and shorter. And 5.0mm palatal sagittal plane has more significance decrease of bone thickness than 2.5mm palatal sagittal plane. According to these results, we can conclude that the palatal installation of miniscrew between 2nd premolar and 1st molar is safest. And it is more safe that comes closer to midpalatal suture and to anterior area in regard to incisive canal.

• Tuberculosis and Respiratory Diseases
• /
• v.53 no.3
• /
• pp.337-343
• /
• 2002

A tracheal bronchus, an aberrant bronchus arising directly from the trachea, is an infrequent congenital anomaly. The incidence of this anomaly ranges from 0.5 to 5%. It usually originates from the right lateral wall of the trachea at the level <2 cm above the tracheal bifurcation. These patients usually are asymptomatic, but some patients may experience recurrent pneumonia, chronic bronchitis, bronchiectasis, or asthmatic episodes. A tracheal bronchus may be associated with other anomalies such as a tracheal stenosis, pulmonary agenesis, pulmonary sequestration, congenital heart disease, a pulmonary venous anomaly and Down's syndrome. This anomaly is usually diagnosed incidentally during bronchoscopy in patients with respiratory problems. Here we report a case of a 20-year-old man with a past history of bronchial asthma, which was incidentally diagnosed as a tracheal bronchus during a medical examination prior to military service, and was associated with a bilateral superior vena cava anomaly.

• Tuberculosis and Respiratory Diseases
• /
• v.58 no.1
• /
• pp.68-73
• /
• 2005

Pulmonary sequestration is a very rare congenital malformation in which a mass of pulmonary tissue is detached from the normal lung and receives its blood supply from a systemic artery. It may be clinically asymptomatic or it has a wide spectrum of various clinical manifestations. The clinical therapeutic approach is to resect the sequestered lobe to prevent frequent complication such as infection. The arterial embolization of feeding artery is a new technique and a less invasive treatment than conventional surgical removal. We have experienced a 17-year-old male with pulmonary sequestration whose complaints were pain in left lower chest. He was diagnosed by computed tomography and aortography and successfully treated with embolization of feeding artery. We report a case of pulmonary sequestration treated with arterial embolization instead of surgery.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.3
• /
• pp.202-209
• /
• 2011

Background: A tuberculous destroyed lung is sequelae of pulmonary tuberculosis and causes various respiratory symptoms and pulmonary dysfunction. The patients with a tuberculous destroyed lung account for a significant portion of those with chronic lung disease in Korea. However, few reports can be found in the literature. We investigated the computed tomography (CT) findings in a tuberculous destroyed lung and the correlation with lung function. Methods: A retrospective analysis was carried out for 44 patients who were diagnosed with a tuberculous destroyed lung at the Keimyung University Dongsan Hospital between January 2004 and December 2009. Results: A chest CT scan showed various thoracic sequelae of tuberculosis. In lung parenchymal lesions, there were cicatrization atelectasis in 37 cases (84.1%) and emphysema in 13 cases. Bronchiectasis (n=39, 88.6%) was most commonly found in airway lesions. The mean number of destroyed bronchopulmonary segments was 7.7 (range, 4~14). The most common injured segment was the apicoposterior segment of the left upper lobe (n=36, 81.8%). In the pulmonary function test, obstructive ventilatory defects were observed in 31 cases (70.5%), followed by a mixed (n=7) and restrictive ventilatory defect (n=5). The number of destroyed bronchopulmonary segments showed a significant negative correlation with forced vital capacity (FVC), % predicted (r=-0.379, p=0.001) and forced expiratory volume in one second ($FEV_1$), % predicted (r=-0.349, p=0.020). After adjustment for age and smoking status (pack-years), the number of destroyed segments also showed a significant negative correlation with FVC, % predicted (B=-0.070, p=0.014) and $FEV_1$, % predicted (B=-0.050, p=0.022). Conclusion: Tuberculous destroyed lungs commonly showed obstructive ventilatory defects, possibly due to bronchiectasis and emphysema. There was negative correlation between the extent of destruction and lung function.

• Korean Journal of Digital Imaging in Medicine
• /
• v.13 no.2
• /
• pp.63-69
• /
• 2011

Table strapis patient fixture for securing the patient movements and falls. if it designed to measure the abdominal circumference and used as an indicator of dose selection at CT scan. it will prevent the overexposure of dose without degradation of image quality and efficiently manage dose of each type of body to technician to deal with CT. First, in order to compare the dose used in CT image and qualitative characteristics. reference image is obtained by examining the abdominal phantom in same conditions with the hospital 120 kVp, 200 mAs, D-Dom (Dynamic Dose Of Modulation). SNR, PSNR, RMSE, MAE, CTDIvol of CT images are compared with reference image. for comparing with reference image, the image that Umbilicus level image of Abdomen CT is stored in the PACS were used. For comparison, the top 12 o'clock portion of the air drawn from the same ROI was measured. CTDIvol, mAs, etc. In order to analyze the characteristics of the image, by measuring the length of the umbilicus circumference, pattern of the dose was analyzed. by using the analyzed perimeter and dose information, To be identified visually, fixed band that scale marked were produced. Use them, If the length of circumference of less than 60 cm 100 mAs, Case of 61~80 cm 120 mAs, Case of 80~100 cm 150 mAs, more than 100 cm 200 mAs, dose selection based on the perimeter, the image was applied. by compare analyzed with the Reference Image, image quality was assessed. by compare with existing tests that equally 200 mAs applied, How much was confirmed that the dose reduction. 1. Depending on the Abdominal circumference, the average PSNR(dB) of the image that differently dose applied was 45.794. 2. Comparing with existing test. the dose of scan that adjusted the mAs depending on the circumference was decreased about 40%. SNR and PSNR of the image that obtained by adjusting the standard mAs based on dose modulation were not much different. Therefore, By choosing a low mAs. dose reduction can be obtained. and the dose selection method that measured Abdominal circumference using a fixed band can protect the overexposure and uniformly apply dose of each type of body to technician to deal with CT.

• Radiation Oncology Journal
• /
• v.18 no.4
• /
• pp.221-225
• /
• 2000

Purpose : This study was designed to examine the reliability of the new version of the AJCC staging system (1997) of nasopharyngeal carcinoma in comparison with the AJCC staging system of 1992. Materials and Methods :Between 1983 and 1996, 185 patients with histologically proven nasopnaryngeal carcinoma were treated with radiation therapy at the Department of Therapeutic Radiology Seoul National University Hospital. For these patients, AJCC staging system of 1992 was compared with the 1997 version by reviewing hospital records, computed tomography (CT) and/or magnetic resonance imaging (MRI). Results :5-year overall suwival rates according to the 1992 and 1997 AJCC staging systems were 100$\%$, and 100$\%$ at stage 1: 100$\%$, and 68.8$\%$ at stage 11; 61.4$\%$, and 63.8$\%$ at stage 111; 61.1$\%$, and 63.2$\%$ at stage IV. S-year overall survival rates of each classification showed significant differences between stages (p=0.0049 for the old version, p=0.01 for the new), but no significant difference was found between the staging systems except at stage 11. Conclusion : The new AJCC staging system allows staging as reliably as the 1992 version, but the adequacy of the newly modified staging classification should be confirmed by further clinical examination.

• Journal of Korean Foot and Ankle Society
• /
• v.7 no.2
• /
• pp.238-249
• /
• 2003

Purpose: To report the clinical result of the intraarticular calcaneus fracture after open reduction and internal fixation with plate by lateral approach. Materials and Methods: Thirty-six calcaneal fractures of 33 patients(29 men and 4 women) were treated by open reduction and internal fixation using an lateral approach from March, 1997 to May, 2002 and were followed more than one year. The autogenous iliac bone graft was done in 2 cases but the others didn't. Radiographically B?hler angle and Gissane angle on simple lateral radiograph were measured and in the 15 cases, the step-off(gap) of posterior facet joint on post-operative CT images were followed. The Salama method was used for evaluation of clinical results. Results: According to Sanders classification, 19 cases of the 36 cases were classified as type II. Type III fracture were found in 12 cases and type IV in 5 cases. The following results were obtained: twenty-two cases(61.1%) out of 36 cases were estimated as good or excellent. The good results or more were obtained in 15 cases(78.9%) in type II and 7 cases(58.3%) in type ill, but no case in type IV. B?hler angles were improved from preoperative average 1.6?to postoperative average 23.4?, Gissane angle was improved from preoperative 107.2?to postoperative 122.8?, respectively. Among 36 cases, Computed tomography was carried out in 15 cases. The postoperative step-off (gap) of posterior facet joint on computed tomography was filled with cancellous bone. Satifactory results was obtained in 7 cases with 2mm gap or less and in 6 cases of 2-5mm. There were no satifactory results in 2 cases with 5mm gap or more. Conclusion: Open reduction and internal fixation for intra-articular fracture of calcaneus was thought to be a good treatment modality. It is thought that the lateral approach is one of the good one for surgical treatment, and that accurate reduction of the posterior facet, acceptable recovery of B?hler angle are more important to obtain best results.