• 제목/요약/키워드: computed tomography, CT

검색결과 2,595건 처리시간 0.033초

Chest-wall Surface Dose During Post-mastectomy Radiation Therapy, with and without Nonmagnetic Bolus: A Phantom Study

  • Choi, Cheon Woong;Hong, Joo Wan;Park, Cheol Soo;Ahn, Jae Ouk
    • Journal of Magnetics
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    • 제21권2호
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    • pp.293-297
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    • 2016
  • For mastectomy patients, sufficient doses of radiation should be delivered to the surface of the chest wall to prevent recurrence. A bolus is used to increase the surface dose on the chest wall, whereby the surface dose is confirmed with the use of a virtual bolus during the computerized treatment-planning process. The purpose of this study is an examination of the difference between the dose of the computerized treatment plan and the dose that is measured on the bolus. Part of the left breast of an Anderson Rando phantom was removed, followed by the attainment of computed tomography (CT) images that were used as the basis for computerized treatment plans that were established with no bolus, a 3 mm-thick bolus, a 5 mm-thick bolus, and a 10 mm-thick bolus. For the computerized treatment plan, a prescribed dose regimen was dispensed daily and planning target volume (PTV) coverage was applied according to the RTOG 1304 guidelines. Using each of the established computerized treatment plans, chest-wall doses of 5 points were measured; this chest-wall dose was used as the standard for the analysis of this study, while the level of significance was set at P < 0.05. The measurement of the chest-wall dose with no bolus is 1.6 % to 10.3 % higher, and the differences of the minimum average and the maximum average of the five measurement points are -13.8 and -1.9, respectively (P < 0.05); however, when the bolus was used, the dosage was measured as 3.7 % to 9.2 % lower, and the differences of the minimum average and the maximum average are 7.4 and 9.0, -1.2 and 17.4, and 8.1 and 19.8 for 3 mm, 5 mm, and 10 mm, respectively (P < 0.05). As the thickness of the bolus is increased, the differences of the average surface dose are further increased. There are a variety of factors that affect the surface dose on the chest wall during post-mastectomy radiation therapy, for which verification is required; in particular, a consideration of the appropriate thickness and the number of uses when a bolus is used, and which has the greatest effect on the surface dose on the chest wall, is considered necessary.

방사선치료 시 자세확인시스템이 처방선량에 미치는 영향 (The Effect of Patients Positioning System on the Prescription Dose in Radiation Therapy)

  • 김정호;배석환
    • 대한방사선기술학회지:방사선기술과학
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    • 제40권4호
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    • pp.613-620
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    • 2017
  • 방사선치료 시 치료계획 선량의 정확한 전달이 중요하다. 뿐만 아니라 정확한 자세 잡이도 필요하다. 하지만 정확한 자세 잡이를 위해서는 자세촬영을 실시하여야 하며 이에 따른 추가적인 방사선 피폭이 발생하게 된다. 이에 자세촬영 주기에 따른 선량분포의 변화를 분석하고자 한다. 팬텀 내 45개 지점에 대해 OSLD를 이용하여 6MV와 10MV 광자선, 그리고 온보드이미지촬영과 콘빔전산화단층촬영에 대한 선량을 측정하였다. 그리고 각 지점에 대한 자세확인촬영이 치료선량에 합산될 경우의 차이값을 비교하였다. 또한 차이값이 미국의학물리협회에서 권고하는 5%를 만족하는 촬영 주기를 제시하고자 하였다. 그 결과 6MV에서는 최소 45.27 cGy에서 최대 98.6 cGy, 10MV에서는 최소 53.34 cGy에서 최대 99.66 cGy, 온보드이미지촬영의 경우 최소 0.19 cGy에서 최대 2.64 cGy, 콘빔전산화단층촬영의 경우 최소 0.54 cGy에서 최대 17.18 cGy가 측정되었다. 치료선량에 대한 자세확인촬영 방사선량의 비율은 2차원 영상의 경우 치료 1회당 최대 3.49%, 3차원 영상의 경우 치료 1회당 최대 22.65%의 오차가 발생된다. 따라서 2차원 영상은 1일 1회, 3차원 영상은 1주 1회까지 허용된다. 향후 추가연구 시 실제 임상적용 시에는 환자자세촬영 종류의 병행에 대한 분리계산이 필요하리라 사료된다.

말초 폐 발생 소형 선암에서 화상적 소견과 병리적, 임상적 예후와의 관계 (The Correlation between Radiologic Findings and Clinicopathological Prognostic Factors in Small Peripheral Adenocarcinoma of Lung)

  • 박재길;조규도;박건;문석환;나석주;최시영;정정임
    • Journal of Chest Surgery
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    • 제37권5호
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    • pp.423-431
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    • 2004
  • 배경 : 폐 말초발생의 소형 선암은 타 조직형태의 폐암들과는 달리 종양의 크기가 예후와 밀접한 관계를 보이지 않아 예후의 예측이 어려운데, 최근 예후와 관련이 있는 화상적 소견들이 보고되고 있다. 이에 저자들은 절제된 소형 폐선암에서 병리적 소견과 예후를 분석하여 화상적 소견들과의 관계를 알아보고자 하였다. 대상 및 방법: 절제술을 시행 받았던 말초 폐 발생 소형 선암증례 중 종양의 최대경이 3cm 이하인 176예를 대상으로 수술 전 HRCT상의 소견들을 분석하였으며, 이들 소견과 병리학적 그리고 임상적 예후인자들과의 관계를 분석하였다. 결과: GGA의 정도가 큰 암일수록 병리학적 그리고 임상적으로 양호한 예후인자를 보였다. 또한 종양의 육안적인 형태에 따른 분류에서도 GGA형 혹은 bubble-like형이 scar-like형 혹은 solid형에 비하여 병리학적 그리고 임상적으로 양호한 예후인자를 나타내었다. 결론: 말초 폐의 소형 선암에서 HRCT 소견은 병리학적 그리고 임상적 예후인자들과 밀접한 관계가 있음이 확인되어, 화상적인 소견에 의하여 절제술 후의 예후를 예측할 수 있을 것으로 생각된다.

Duration of Regain of Deep Pain Perception after Decompression Surgery as a Parameter of Surgical Outcome for Acute Thoracolumbar Disc Herniation Hansen Type I with Loss of Deep Pain Perception in Dogs

  • Park, Sung-Su;Lim, Ji-Hey;Byeon, Ye-Eun;Jang, Byung-Jun;Ryu, Hak-Hyun;Uhm, Ji-Yong;Kang, Byung-Jae;Kim, Wan-Hee;Kweon, Oh-Kyeong
    • 한국임상수의학회지
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    • 제25권6호
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    • pp.529-532
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    • 2008
  • The object of this study was to evaluate the durations from onset of neurological sign until surgery and regaining of the deep pain perception (DPP) after decompression as prognostic indicators for the outcome of decompression surgery in dogs with thoracolumbar intervertebral disc disease (IVDD). The compression lesions in the thoracolumbar vertebrae were localized by plain radiograph, computed tomography and neurological examination in 28 dogs with hindlimb paralysis. The follow up was carried out for 6 months after laminectomy. During the follow up, regaining DPP and walking ability were evaluated. Improvement to normal or paretic gait after surgery was judged as success of the surgical treatment.The success rate of surgical treatment was 70 % (7 out of 10 dogs) when surgical intervention was carried out within 24 hours but 38.9 % (7 out of 18) over 24 hours (P<0.05). The success rate of surgical treatment was 87.5 % (14 out of 16 dogs) when DDP was regained within 5 weeks after surgery but there was 0 % (0 out of 12 dogs) when DDP was not regained within 5 weeks after surgery (P<0.05). Other parameters such as compression rate in CT scan and laminectomy methods did not related with the success of the surgery. These results suggested that the time of surgery after onset and duration of regaining of DPP after decompression were useful parameter to predict the success of surgical treatment for thoracolumbar disc herniation in dogs.

병리특이적 형태분석 기법을 이용한 HRCT 영상에서의 새로운 봉와양폐 자동 분할 방법 (A Novel Method for Automated Honeycomb Segmentation in HRCT Using Pathology-specific Morphological Analysis)

  • 김영재;김태윤;이승현;김광기;김종효
    • 정보처리학회논문지:소프트웨어 및 데이터공학
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    • 제1권2호
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    • pp.109-114
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    • 2012
  • 봉와양폐(Honeycomb)는 직경 2~10mm 정도의 크기가 같지 않은 낭포(Cyst)가 경계가 명확한 섬유질(Fibrosis)로 이루어진 벽에 둘러싸여 밀집된 형태로 이루어져 있다. 봉와양폐가 발견될 경우 급성악화의 발생 빈도가 높으며 따라서 봉와양폐의 관찰 여부와 측정은 임상에서 중요한 지표가 된다. 따라서 본 논문에서는 봉와양폐 영역의 정량적 측정을 위하여 봉와양폐의 특징을 이용한 형태학적 기법과 군집성 평가 기법을 통해 자동 구획 방법을 제안하였다. 첫 번째로 영상의 잡음을 제거하기 위하여 가우시안 필터링을 적용하고, 모폴로지 기법 중 팽창 기법을 이용하여 폐 영역을 구획하였다. 두번째로, 주변 8방향 검사를 통해 봉와양폐를 구성하는 낭포의 후보군을 찾고, 영역 확장과 외곽선 검사를 통해 비 낭포들을 제거하였다. 마지막으로 군집화 검사를 통해 최종적으로 봉와양폐를 구획하였다. 제안한 방법은 80장의 고해상도 컴퓨터 단층촬영 영상에서 실험한 결과, 89.4%의 민감도와, 72.2%의 양성 예측도를 보였다.

독실라민 중독시 발생할 수 있는 발작의 특성과 위험인자 (The Clinical Features and Risk Factors of Seizure After Doxylamine Intoxication)

  • 송범수;이기만;김선욱;유제성;정태녕;박유석;정성필;구홍두;박인철
    • 대한임상독성학회지
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    • 제8권2호
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    • pp.88-96
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    • 2010
  • Purpose: Doxylamine is antihistamine drug that is used as a hypnotic. It is also used for suicidal attempts because it can be easily purchased at the pharmacy without a prescription. There were many articles about the complications after doxylamine intoxication such as a rhabdomyolysis, but only a few articles have reported on seizure. We reviewed the cases of doxylamine intoxication with seizure that were treated in the emergency department. Methods: We reviewed the medical records of the patients who were over 15 years old and who were intoxicated by doxylamine at 3 emergency medical centers from January 2006 to June 2010. We reviewed the patients' age, gender, the dose of doxylamine ingested, if gastrointestinal decontamination was done, the time from intoxication to hospital arrival, the seizure history, treatment of seizure, the electroencephalography (EEG) results, the brain computed tomography (CT) results and the blood test results. Results: There were 168 patients who were intoxicated by doxylamine during the study period. Twelve patients had a seizure episode. The differences between the patients who developed seizure and the patients who did not were the dose and the serum levels of sodium and creatinine. The only clinically meaningful difference was the amount of doxylamine. The amount of doxylamine ingested (>29 mg/kg) predicted the development of seizure with a sensitivity of 75% and a specificity of 92% on the ROC curve. One patient among the seizure patients expired in the emergency department. Conclusion: In case of doxylamine intoxicated patients, there is close relationship between seizure and ingested amount, so close observation needs to be done for the patients who ingest too much because doxylamine can cause death. Further prospective studies are needed for doxylamine intoxicated patients with a seizure episode.

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Positional changes of the mandibular condyle in unilateral sagittal split ramus osteotomy combined with intraoral vertical ramus osteotomy for asymmetric class III malocclusion

  • Park, Jun;Hong, Ki-Eun;Yun, Ji-Eon;Shin, Eun-Sup;Kim, Chul-Hoon;Kim, Bok-Joo;Kim, Jung-Han
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제47권5호
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    • pp.373-381
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    • 2021
  • Objectives: In the present study, the effects of sagittal split ramus osteotomy (SSRO) combined with intraoral vertical ramus osteotomy (IVRO) for the treatment of asymmetric mandible in class III malocclusion patients were assessed and the postoperative stability of the mandibular condyle and the symptoms of temporomandibular joint disorder (TMD) evaluated. Materials and Methods: A total of 82 patients who underwent orthognathic surgery for the treatment of facial asymmetry or mandibular asymmetry at the Department of Oral and Maxillofacial Surgery, Dong-A University Hospital, from 2016 to 2021 were selected. The patients that underwent SSRO with IVRO were assigned to Group I (n=8) and patients that received bilateral SSRO (BSSRO) to Group II (n=10, simple random sampling). Preoperative and postoperative three-dimensional computed tomography (CT) axial images obtained for each group were superimposed. The condylar position changes and degree of rotation on the superimposed images were measured, and the changes in condyle based on the amount of chin movement for each surgical method were statistically analyzed. Results: Group I showed a greater amount of postoperative chin movement. For the amount of mediolateral condylar displacement on the deviated side, Groups I and II showed an average lateral displacement of 0.07 mm and 1.62 mm, respectively, and statistically significantly correlated with the amount of chin movement (P=0.004). Most of the TMD symptoms in Group I patients who underwent SSRO with IVRO showed improvement. Conclusion: When a large amount of mandibular rotation is required to match the menton to the midline of the face, IVRO on the deviated side is considered a technique to prevent condylar torque. In the present study, worsening of TMD symptoms did not occur after orthognathic surgery in any of the 18 patients.

완전무치악 환자에서 디지털 가이드 수술 방식을 이용한 무피판절개 임플란트 식립증례: 증례보고 및 5년 추적관찰 (Flapless implant placement with digital 3D imaging and planning system in fully edentulous patient: A case report and 5-year follow-up)

  • 신미선;백장현
    • 대한치과보철학회지
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    • 제57권3호
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    • pp.312-320
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    • 2019
  • 디지털 방식을 이용한 치과 임플란트 진료에서 가장 주목받는 분야 중 하나가 디지털 소프트웨어와 컴퓨터 단층촬영을 이용하여 수술용 스텐트를 제작, 임플란트를 식립하는 분야이다. 컴퓨터를 이용한 디지털 임플란트 치료계획 시스템과 이를 이용한 수술용 가이드는 예지성과 심미성, 기능성을 갖춘 임플란트의 식립과 수복을 가능하게 한다. 특히 이러한 가이드 수술은 임플란트 수복물의 형태와 기능을 고려한 임플란트의 식립 시 더욱 유리하다. 최근 여러 제조사에서 보철물 제작을 위해 치과용 스캔부터 제작방법까지 다양한 디지털 방식의 제작과정을 제시하고 있다. 이러한 방법들은 정확하고 예지성 있는 예후를 위해 여러 연구자들에 의해 연구되어지고 있으며, 점차 발전하고 있다. 이번 증례는 완전무치악의 여성 환자에서 임플란트 고정성 보철물을 이용한 수복증례이다. 하악은 all-on-four 방식을 적용하여 4개의 임플란트를 식립하였으며, 상악은 이에 기초하여 6개의 임플란트를 식립하였다. 최종보철물에 기초한 임플란트의 식립을 위해 임플란트 수술용 스텐트를 이용하였으며, 환자는 치료 결과에 만족하였으며, 5년 추적관찰 결과, 임플란트와 보철물 모두 안정적으로 유지되고 있다.

하악 제1대구치에서 Radix Entomolaris의 발현빈도와 치근의 개수에 따른 근관 입구들 사이의 위치 관계에 대한 연구 (A study on Radix Entomolaris about prevalence and correlation of canal orifices location according to number of roots in mandibular first molars)

  • 장지혜;김진우;조경모;김수연;박세희
    • 대한치과의사협회지
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    • 제56권12호
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    • pp.695-706
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    • 2018
  • Objectives: The purpose of this study was to investigate the ratio of 4 root canals and the incidence of Radix Entomolaris in mandibular first molars and find out anatomical difference according to number of roots by analysis of cone-beam CT images in a Korean population. Materials and Methods: Total 142 images containing mandibular first molars were selected from CBCT images taken from 2013 to 2017 at Gangneung-Wonju National University Dental Hospital. After reconstructing the image with reference to the Cemento-enamel junction, the root canals were detected at the bottom of the pulpal floor and the number of roots and root canals were analyzed. Various lengths and MLO-DLO-DBO angle were measured between each canal orifices and the external contour line of the tooth, and the distolingual canal wall thickness was measured. Student t-test was used for statistical significance. Results: Among the total 142 teeth, 4 canals were 42.2% and Radix Entomolaris was 25.3%. As the results of measuring various lengths and the angle, the distolingual canal orifice in Group 2(with Radix Entomolaris) tends to deviate to the lingual side than the mesiolingual canal orifice and to the mesial side than the distobuccal canal orifice. Besides, thickness of the distolingual canal wall in Group 2(with Radix Entomolaris) was significantly thinner than that of Group 1 at every level except pulpal floor level. Conclusion: It is necessary to consider the difference according to the presence of Radix Entomolaris in endodontic treatment.

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Sensory change after implant surgery: related factors for recovery

  • Jung, Joon-Ho;Ko, Ji-Hoon;Ku, Jeong-Kui;Kim, Jae-Young;Huh, Jong-Ki
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제48권5호
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    • pp.297-302
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    • 2022
  • Objectives: This retrospective study aimed to analyze data on nerve damage in patients who complained of sensory changes after dental implant surgery, the clinical results according to proximity of the implant fixture to the inferior alveolar nerve (IAN) canal, and the factors affecting recovery of sensation. Materials and Methods: The electronic medical records of 64 patients who had experienced sensory change after implant surgery were reviewed. Patients were classified by sex, age, implant installation sites, recovery rate and the distance between the implant fixture and IAN canal on computed tomography (CT). The distance was classified into Group I (D>2 mm), Group II (2 mm≥D>0 mm), and Group III (D≤0 mm). Results: The 64 patients were included and the mean age was 57.3±7.3 years. Among the 36 patients who visited our clinic more than two times, 21 patients (58.3%) reported improvement in sensation, 13 patients (36.1%) had no change in sensation, and 2 patients (5.6%) reported worsening sensation. In Group II, symptom improvement was achieved in all patients regardless of the removal of the implant fixture. In Group III, 8 patients (40.0%) had reported symptom improvement with removal of the implant fixture, and 2 patients (33.3%) of recovered patients showed improvement without removal. Removal of the implant fixture in Group III did not result in any significant difference in recovery (P=0.337), although there was a higher possibility of improvement in sensation in removal cases. Conclusion: Clinicians first should consider removing the fixture when it directly invades the IAN canal. However, in cases of sensory change after dental implant surgery where the drill or implant fixture did not invade the IAN canal, other indirect factors such as flap elevation and damage due to anesthesia should be considered as causes of sensory change. Removal of the implant should be considered with caution in these situations.