• The Korean Journal of Pain
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• 제33권3호
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• pp.267-274
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• 2020

Background: General anesthesia (GA) has been considered the anesthetic technique which most frequent leads to phantom limb pain (PLP) after a limb amputation. However, these prior reports were limited by small sample sizes. The aims of this study were to evaluate the incidence of PLP according to the various anesthetic techniques used for limb amputation and also to compare the occurrence of PLP according to amputation etiology using the Korean Health Insurance Review and Assessment Service for large-scale demographic information. Methods: The claims of patients who underwent limb amputation were reviewed by analyzing the codes used to classify standardized medical behaviors. The patients were categorized into three groups-GA, neuraxial anesthesia (NA), and peripheral nerve block (PNB)-in accordance with the anesthetic technique. The recorded diagnosis was confirmed using the diagnostic codes for PLP registered within one year after the limb amputation. Results: Finally, 7,613 individuals were analyzed. According to the recorded diagnoses, 362 patients (4.8%) developed PLP after amputation. Among the 2,992 patients exposed to GA, 191 (6.4%) were diagnosed with PLP, whereas 121 (4.3%) of the 2,840 patients anesthetized with NA, and 50 (2.8%) of the 1,781 patients anesthetized under PNB developed PLP. The relative risks were 0.67 (95% confidence interval [CI], 0.53-0.84; P < 0.001) for NA and 0.43 (95% CI, 0.32-0.59; P < 0.001) for PNB. Conclusions: In this retrospective cohort study, using large-scale population-based databases, the incidence rates of PLP after limb amputations were, in the order of frequency, GA, NA, and PNB.

• 대한의용생체공학회:의공학회지
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• 제44권3호
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• pp.182-189
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• 2023

CT is a medical device that acquires medical images based on Attenuation coefficient of human organs related to X-rays. In addition, using this theory, it can acquire sagittal and coronal planes and 3D images of the human body. Then, CT is essential device for universal diagnostic test. But Exposure of CT scan is so high that it is regulated and managed with special medical equipment. As the special medical equipment, CT must implement quality control. In detail of quality control, Spatial resolution of existing phantom imaging tests, Contrast resolution and clinical image evaluation are qualitative tests. These tests are not objective, so the reliability of the CT undermine trust. Therefore, by applying an artificial intelligence classification model, we wanted to confirm the possibility of quantitative evaluation of the qualitative evaluation part of the phantom test. We used intelligence classification models (VGG19, DenseNet201, EfficientNet B2, inception_resnet_v2, ResNet50V2, and Xception). And the fine-tuning process used for learning was additionally performed. As a result, in all classification models, the accuracy of spatial resolution was 0.9562 or higher, the precision was 0.9535, the recall was 1, the loss value was 0.1774, and the learning time was from a maximum of 14 minutes to a minimum of 8 minutes and 10 seconds. Through the experimental results, it was concluded that the artificial intelligence model can be applied to CT implements quality control in spatial resolution and contrast resolution.

• 한국의학물리학회지:의학물리
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• 제25권1호
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• pp.1-7
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• 2014

온열 치료는 방사선치료와 병행했을 때 종양에 대한 효과적인 치료방법이다. 환자의 안전과 효과적인 치료를 위해서는 가온 시 인체의 온도의 분포를 확인하는 것이 중요하다. 본 연구는 사용중인 고주파온열치료기와 제조사가 권하고 있는 protocol를 이용하여 펜톰의 온도를 높여주었다. 온도측정에 사용된 펜톰은 한천(agar)으로 5 cm두께로 단면을 측정할 수 있게 제작되었다. 가온 시 온도의 분포는 에너지가 클수록 온도가 높게 올라갔으며, 온도 분포는 에너지에 상관없이 비슷한 영역이 가온되었다. 아래쪽보다 위쪽으로 온도가 높게 올라가는 경향을 보이고 있으며, 큰 전극보다는 작은 전극을 사용했을 때 온도가 높게 올라가고 치우치는 온도분포를 보인다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.73-76
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• 1996

Computer simulation and magnetic resonance angiograms(MRAs) are used to understand for flow patterns in the carotid arterial bifurcation. Steady momentum equation is solved by the finite volume method. A Phantom of the carotid artery made of bioacrylic material is used for MRA observation. Flow Patterns are observed by using MRA for flow in the phantom of an automatic closed-type circulatory system filled with sugar 4 w% solution. For numerical analysis the idealized geometric shape of the carotid artery is constructed to portray the phantom. Results of numerical analysis are compared with those of MRA. The flow patterns of the phantom on MRA are almost identical to those of the computer simulation.

• 한국응용과학기술학회지
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• 제16권4호
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• pp.329-335
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• 1999

The influences of fluorophor, scatterer, and absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength. The molecular properties have been studied by laser induced fluorescence spectroscopy in phantom. It has been found that the effects of optical properties in scattering media could be investigated by the optical parameters(${\mu}_a$, ${\mu}_a$, ${\mu}_t$). Experimental and Monte Carlo Simulation method for modelling light transport in tissue was applied. The experimental results using a phantom were discussed and compared with those obtained through Monte Carlo Simulation. It may also aid in designing the best model for oil chemistry, medicine and application of medical engineering.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 1999년도 Japanese Journal of Medical Physics
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• pp.420-420
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• 1999

• 한국의학물리학회지:의학물리
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• 제18권1호
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• pp.27-34
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• 2007

호흡운동 조절 방사선치료 시 환자체표면 움직임을 추적하여 실시간 보정하고자 한다. 본 연구에서 사용한 시스템은 치료테이블에 기반을 둔 동 팬텀(CBMP, couch based computer-controlled motion phantom), 초음파 센서 및 제어, 구동, 분석 프로그램 등으로 구성하였다 동물실험 결과 호흡주기는 2.9초이었고, 호흡진폭은 6mm이었다. 실시간 체표면 추적시스템의 유용성 평가에 중요한 항목인 호흡운동 획득-보정간의 지연시간은 $2.34{\times}10^{-4}sec$ 초이어서 호흡운동 조절 방사선치료 시 사용할 수 있는 새로운 실시간 체표면 추적 기술의 임상적용에의 가능성을 확인할 수 있었다.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.160-166
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• 2019

This study examined the clinical use of two newly installed computed tomography (CT) simulators in the Department of Radiation Oncology. The accreditation procedure was performed by the Korean Institute for Accreditation of Medical Imaging. An Xi R/F dosimeter was used to measure the CT dose index for each plug of the CT dose index phantom. Image qualities such as the Hounsfield unit (HU) value of water, noise level, homogeneity, existence of artifacts, spatial resolution, contrast, and slice thickness were evaluated by scanning a CT performance phantom. All test items were evaluated as to whether they were within the required tolerance level. CT calibration curves-the relationship between CT number and relative electron density-were obtained for dose calculations in the treatment planning system. The positional accuracy of the lasers was also evaluated. The volume CT dose indices for the head phantom were 22.26 mGy and 23.70 mGy, and those for body phantom were 12.30 mGy and 12.99 mGy for the first and second CT simulators, respectively. HU accuracy, noise, and homogeneity for the first CT simulator were -0.2 HU, 4.9 HU, and 0.69 HU, respectively, while those for second CT simulator were 1.9 HU, 4.9 HU, and 0.70 HU, respectively. Five air-filled holes with a diameter of 1.00 mm were used for assessment of spatial resolution and a low contrast object with a diameter of 6.4 mm was clearly discernible by both CT scanners. Both CT simulators exhibited comparable performance and are acceptable for clinical use.

• 한국의학물리학회지:의학물리
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• 제25권1호
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• pp.23-30
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• 2014

방사선치료에서는 환자 체내에 전달된 선량이 원래 의도한 데로 분포되는 지 확인하기 위하여 균질한 팬텀을 이용한 정도 관리를 치료 전에 주로 시행하고 있다. 하지만 균질한 팬텀을 이용한 정도 관리는 표면이 불규칙적이고 불균질한 인체에 대한 선량분포를 완전히 보증해 주지는 못하고 있다. 본 연구에서는 환자를 투과하는 선량의 분포를 측정하여 역으로 환자체내 선량 분포를 계산하는 투과선량 기반 체내선량 검증프로그램을 개발하였다. 투과선량은 주방사선과 산란방사선으로 이루어져 있는데, 본 연구에서는 전자포탈영상장치로 측정한 선량분포로부터 주방사선만을 이용한 간단한 식으로 환자체내선량분포를 계산하는 프로그램과 감마값 분포를 평가하여 두 선량분포를 서로 비교할 수 있는 프로그램을 개발하였다. 개발된 프로그램을 이용하여 계산한 팬텀의 등중심점을 지나는 관상면의 체내선량 분포는 치료계획시스템에서 제공하는 동일 평면의 선량분포와의 비교결과 균질팬텀에서 평균 95%, 비균질팬텀에서 81.8%의 감마통과율을 보였다.

• Radiation Oncology Journal
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• 제4권2호
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• pp.173-177
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• 1986

온열요법이 암환자치료에 있어 온열요법 단독 또는 방사선치료나 일부 항암화학요법제와 병행할 때 그 효과가 상승되고 있음은 최근 잘 알려진 사실이다. 가톨릭의대부속 강남성모병원 방사선치료실에서는 온열요법의 동물실험과 더 나아가 임상응용을 목적으로 가정용 전자레인지를 개조하여 극초단파유도관을 제작, 부착시킴으로서, 실험 및 종양부위에 2,450MHz 극초단파를 조사할 수 있는 장치를 제작하였다. 아울러 이 온열치료장치가 온열치료기로서의 적합성을 알아보기 위하여 본 실험을 실시하였다. 실험을 위한 phantom으로, 고기덩어리와 한천을 이용하였으며, 마우스하지에 발생시킨 Sarcom-180고형종양을 또한 이용하여, 이 온열치료기의 전압변동에 따른 온도분포 변화를 측정하였다. 한편 실험동물종양에서는 종양조직내 온도가 주위 정상조직보다 $1\~3^{\circ}C$ 높은 것을 확인할 수 있었다.