• Progress in Medical Physics
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• v.21 no.3
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• pp.281-290
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• 2010

Cone-beam digital tomosynthesis (CBDT) has greatly been paid attention in the image-guided radiation therapy because of its attractive advantages such as low patient dose and less motion artifact. Image quality of tomograms is, however, dependent on the imaging conditions such as the scan angle (${\beta}_{scan}$) and the number of projection views. In this paper, we describe the principle of CBDT based on filtered-backprojection technique and investigate the optimization of imaging conditions. As a system performance, we have defined the figure-of-merit with a combination of signal difference-to-noise ratio, artifact spread function and floating-point operations which determine the computational load of image reconstruction procedures. From the measurements of disc phantom, which mimics an impulse signal and thus their analyses, it is concluded that the image quality of tomograms obtained from CBDT is improved as the scan angle is wider than 60 degrees with a larger step scan angle (${\Delta}{\beta}$). As a rule of thumb, the system performance is dependent on $\sqrt{{\Delta}{\beta}}{\times}{\beta}^{2.5}_{scan}$. If the exact weighting factors could be assigned to each image-quality metric, we would find the better quantitative imaging conditions.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.75-83
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• 2010

Purpose: It aims to evaluate the location change and tendency of hepatic and intrahepatic tumors according to gastric volume and change of location. Materials and Methods: It studied 9 patients with hepatic tumors who visited Gangnam Severance Hospital from March 2009 to April 2010 and who underwent CT or PET (Positron Emission Tomography) within 2 weeks before CT-simulation. The patients fasted for 6 hours before CT-simulation and drank 240~250 cc of water just before CT or PET for image fusion. Those two types of images were fused to RTP (Radiation Treatment Planning, Pinnacle 8.0h) focusing on bone structure of individual patients. Results: They drank 240~260 cc of water but their stomach volume after drinking water varied from 259.3 cc to 495.4 cc. Even though individual differences existed in the change of stomach volume before and after drinking water, the volume was increased by 130 cc (174%) on average. The change in absolute distance between the centers of tumors ranged from 0.52 cm to 3.04 cm (1.52 cm on average); from 0.1 cm to 1.35 cm (0.44 cm on average) in cranial-caudal direction; from 0.05 cm to 2.75 cm (1.22 cm on average) in left-right direction; and from 0.05 cm to 1.85 cm (0.33 cm on average) in ventral-dorsal direction. Conclusion: It is hard to predict the movement of tumors by observing stomach movement, due to great individual differences; however, it was observed that the location of hepatic tumors was right-sided as the stomach was filled with water. Thus, it is recommended to maintain the fastened state to secure the accuracy of hepatic tumor treatment. If it cannot maintain the fastened state, it is recommended to measure stomach volumes and movement in the patient to consider the movement of hepatic tumors before radiation treatment.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.481-491
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• 1995

Background: Recently there has been a trend of an increasing incidence of mediastinal tuberculous lymphadenitis(MTL) in adults. MTL often cause bronchial stenosis or esophago-mediastinal fistula. In spite of effective treatment, it is difficult to cure. Moreover, relapse frequently occurs. Authors analyzed chest CT findings and clinical features of 29 cases with MTL Methods: 29 cases with MTL were retrospectively studied with the clinical and radiologic features from April 1990 to March 1995 Results: 1) A total of 29 cases were studied. 12 cases were male and 17 cases were female. The male to female ratio was 1:1.4 Mean age was 29 years old. The 3rd decade(45%) was the most prevalent age group 2) The most common presenting symptoms and signs were palpable neck masses(62%) followed by cough(59%) and sputum(38%) 3) Except in one case of MTL, all patients had coexisting pulmonary tuberculosis, cervical tuberculous lymphadenitis, endobronchial tuberculosis and tuberculous pleurisy. Among the coexisting tuberculous diseases, Pulmonary tuberculosis was the most common(76%) 4) On simple chest X-ray, mediastinal enlargement was noted in 21 cases(72%), but it was not noted in 8 cases(28%). The most frequently involving site was the paratracheal node in 16 cases(72%). Rt side predominence(73%) was noted 5) Patterns of node appearance on a postcontrast CT scan were classified into 3 types. There were 19 cases(30%) of the Homogenous type, 30 cases(47%) of the Central low density type and 15 cases(23%) of the Peripheral fat obliteration type. The most common type was the central low density type. The most common lymph node size was 1~2 cm(88%) 6) The most frequently involved site was the paratracheal node in 26 cases(89%) by chest CT. Rt side(63%) was predominant 7) 9 cases(43%) had complete therapy and most common treatment duration was 13 - 18 months. 12 cases(57%) had incomplete continuing antituberculous medication and half of the cases had been treated above 19 months. Conclusion: Chest CT findings of MTL showed central low density area and peripheral rim enhancement, so this characteristic findings could differentiate it from other mediastinal diseases and help a diagnosis of tuberculosis. In spite of effective antituberculous medication, it is difficult to cure. Moreover, relapse frequently occurs. Further studies will be needed of the clinical features and the treatment of MTL.

• Journal of Chest Surgery
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• v.35 no.9
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• pp.692-696
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• 2002

Pulmonary artery sarcoma is a rare disease and hard to diagnose; therefore, suspicion is very important for the diagnosis and treatment. Surgical resection is almost always needed because of progressive right heart failure. Adjuvant chemotherapy and radiation therapy are still controversial. We report a case of a 42-year-old man who had a right pulmonary arterial tumor Curative resection was impossible because the tumor invaded the left pulmonary artery. Palliative endarterectomy was performed followed by radiation therapy. The patient refused the chemotherapy. Until the postoperative 6th month, the residual tumor was stable. However, 15 months later, follow-up chest computed tomography revealed a metastatic pulmonary nodule at left lower lobe and the increased residual tumor. The patient received chemotherapy with limited tumor response. The metastatic nodule and residual tumor did not increase but bone scan revealed a rib metastasis at postoperative 24 months. He will be receiving additional chemotherapy.

• Korean Journal of Biological Psychiatry
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• v.2 no.2
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• pp.169-176
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• 1995

두부 외상은 많은 발생율과 사망율을 차지하고 있으며, 건강한 생활을 위해 큰 관심을 갖게 되었다. 신경방사선영상은 외상성 뇌손상 환자들의 진단과 치료에 필수적인 방법이다. 뇌손상의 기본 기전, 병리, 그리고 영상 소견을 이해 하는 것은 매우 중요하다. 1970년대에 Glasgow coma scale의 형상과 전산화단층촬영(CT)의 발달은 임상의사들이 두부외상에 대한 평가와 환자들의 경과를 예상하는데 극적인 변화를 주었다. 최근 자기공명영상(MRI)의 발달로 외상성 뇌손상의 형태를 더욱 이해 하게 되었고, 두부 외상의 발견율이 높아지게 되었다.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.767-774
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• 1999

Background : Tuberculous mediastinal lymphadenitis (TML) is a relatively commonly encountered in Korea. However, there were no datas available on TML without other combined tuberculous infections in Korea. We retrospectively analyzed clinical manifestations, radiologic findings, Chest CT scan findings, the duration of treatment, and follow up Chest CT scan findings of 23 cases who had only TML. Method : 23 cases from 1991 to 1997 with TML confirmed by biopsy and had no other combined tuberculous infections were studied retrospectively. Results : Of the 23 cases, 7 cases were male and 16 female. The male to female ratio was 1 : 2.4. Mean age was 31 years and the most prevalent age group was the 3rd decade(43%). The most common presenting symptoms were fever(39%) followed by no symptom, cough, swallowing difficulty, and chest discomfort. On simple chest X-ray, mediastinal enlargement were noted in 20 cases(90%). The most frequently involved site was the paratracheal node in 11 cases with the right to left side involvement ratio being 4.6 : 1. On chest CT scan, the most commonly enlarged node was the paratracheal node(33%) followed by the subcarinal(20%), hilar(13%), tracheobronchial (8%), subaortic(8%), supraclavicular(8%) and anterior. mediastinal nodes. 6 cases were dropt out due to incomplete follow up. Thirteen cases were treated with HERZ regimen and the mean duration of treatment was 14 months. Three cases were treated with second line drug regimens(Tarivid, Pyrazinamide, Streptomycin plus Ethambutol or Para-aminosalicylic acid) for 18 months. In HERZ groups, one case was recurred after 10 months later and retreatment was done by same HERZ regimen during 12 months. Follow up chest CT scan after completion of treatment were done in 13 cases and that revealed more than a 50% decrease in size in 77% of the cases and no interval change in 23% of the cases. Conclusion : In cases of TML without other combined tuberculous infection, the minimal duration of treatment was required 12 months by HERZ regimen and 18 months by a 2nd line regimen or more. Further studies will be needed to confirm the treatment duration for TML without other combined tuberculous infections.

• Radiation Oncology Journal
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• v.10 no.2
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• pp.227-236
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• 1992

From March 1979 through December 1986, 232 previously untreated patients with invasive carcinoma of the uterine cervix stage IIB were treated at the Department of Therapeutic Radiology, Seoul National University Hospital. The patients studied were staged according to the FIGO recommendations and the majority of patients were treated with external beam whole pelvis radiation and intracavitary radiation. Pretreatment parameters, including physical examination findings, blood parameters, prior medical illnesses, histology and abdomino-pelvic CT findings were studied, employing univariate and multivariate analyses to identify the potentially significant prognostic factors on locoregional control, disease free survival and overall survival. Histology, extent of parametrial involvement on physical examination and paraaortic lymph node metastasis on CT were found to have prognostic significance in the carcinoma of uterine cervix stage IIB.

• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.250-250
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• 2002

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.69-75
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• 2013

Purpose: Transbronchial brachytherapy used in the two-dimensional treatment planning difficult to identify the location of the tumor in the affected area to determine the process analysis. In this study, we have done a comparative analysis for the patient's treatment planning using a CT simulator. Materials and Methods: The analysis was performed by the patients who visited the hospital to June 2012. The patient carried out CT-image by CT simulator, and we were plan to compare with a two-dimensional and threedimensional treatment planning using a Oncentra Brachy planning system (Nucletron, Netherland). Results: The location of the catheter was confirmed the each time on a treatment planning for fractionated transbronchial brachytherapy. GTV volumes were $3.5cm^3$ and $3.3cm^3$. Also easy to determine the dose distribution of the tumor, the errors of a dose delivery were confirmed dose distribution of the prescibed dose for GTV. In the first treatment was 92% and the second was 88%. Conclusion: In order to compensate for the problem through a two-dimensional treatment planning, it is necessary to be tested process for the accurate identification and analysis of the treatment volume and dose distribution. Quantitatively determine the dose delivery error process that is reflected to the treatment planning is required.

• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.191-196
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• 2014

The purpose of this study is to evaluate the reproducibility and usefulness of an image through the fusion of the computed tomography image and the magnetic resonance image by using a self-produced phantom when planning the treatment, and also to compare and analyze the target dose on the acquired image. The size of small hole and the reproducibility of capacity existed in the phantom on the image of the phantom obtained by the computed tomography and the magnetic resonance image of the phantom scanning with different intensity of magnetic field are compared, and the change of dose in the random target is compared and analyzed.