• 대한약리학회:학술대회논문집
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• 2006.10a
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• pp.119.2-119.2
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• 2006

• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.50-64
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• 2024

Background: The reference dose coefficients (DCs) of the International Commission on Radiological Protection (ICRP) have been widely used to estimate organ doses of individuals for risk assessments. This approach has been well accepted because individual anatomy data are usually unavailable, although dosimetric uncertainty exists due to the anatomical difference between the reference phantoms and the individuals. We attempted to quantify the individual variation of organ doses for photon external exposures by calculating and comparing organ DCs for 30 individuals against the ICRP reference DCs. Materials and Methods: We acquired computed tomography images from 30 patients in which eight organs (brain, breasts, liver, lungs, skeleton, skin, stomach, and urinary bladder) were segmented using the ImageJ software to create voxel phantoms. The phantoms were implemented into the Monte Carlo N-Particle 6 (MCNP6) code and then irradiated by broad parallel photon beams (10 keV to 10 MeV) at four directions (antero-posterior, postero-anterior, left-lateral, right-lateral) to calculate organ DCs. Results and Discussion: There was significant variation in organ doses due to the difference in anatomy among the individuals, especially in the kilovoltage region (e.g., <100 keV). For example, the red bone marrow doses at 0.01 MeV varied from 3 to 7 orders of the magnitude depending on the irradiation geometry. In contrast, in the megavoltage region (1-10 MeV), the individual variation of the organ doses was found to be negligibly small (differences <10%). It was also interesting to observe that the organ doses of the ICRP reference phantoms showed good agreement with the mean values of the organ doses among the patients in many cases. Conclusion: The results of this study would be informative to improve insights in individual-specific dosimetry. It should be extended to further studies in terms of many different aspects (e.g., other particles such as neutrons, other exposures such as internal exposures, and a larger number of individuals/patients) in the future.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.226-232
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• 2015

Purpose: Toxicity of mucosa is one of the major concerns of radiotherapy (RT), when a target tumor is located near a mucosal lined organ. Energy of photon RT is transferred primarily by secondary electrons. If these secondary electrons could be removed in an internal cavity of mucosal lined organ, the mucosa will be spared without compromising the target tumor dose. The purpose of this study was to present a RT dose reduction in near target inner-surface (NTIS) of internal cavity, using Lorentz force of magnetic field. Materials and Methods: Tissue equivalent phantoms, composed with a cylinder shaped internal cavity, and adjacent a target tumor part, were developed. The phantoms were irradiated using 6 MV photon beam, with or without 0.3 T of perpendicular magnetic field. Two experimental models were developed: single beam model (SBM) to analyze central axis dose distributions and multiple beam model (MBM) to simulate a clinical case of prostate cancer with rectum. RT dose of NTIS of internal cavity and target tumor area (TTA) were measured. Results: With magnetic field applied, bending effect of dose distribution was visualized. The depth dose distribution of SBM showed 28.1% dose reduction of NTIS and little difference in dose of TTA with magnetic field. In MBM, cross-sectional dose of NTIS was reduced by 33.1% with magnetic field, while TTA dose were the same, irrespective of magnetic field. Conclusion: RT dose of mucosal lined organ, located near treatment target, could be modulated by perpendicular magnetic field.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.676-683
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• 2007

A non-invasive respiratory gated radiotherapy system like those based on external anatomic motion gives better comfortableness to patients than invasive system on treatment. However, higher correlation between the external and internal anatomic motion is required to increase the effectiveness of non-invasive respiratory gated radiotherapy. Both of invasive and non-invasive methods need to track the internal anatomy with the higher precision and rapid response. Especially, the non-invasive method has more difficulty to track the target position successively because of using only image processing. So we developed the system to track the motion for a non-invasive respiratory gated system to accurately find the dynamic position of internal structures such as the diaphragm and tumor. The respiratory organ motion tracking apparatus consists of an image capture board, a fluoroscopy system and a processing computer. After the image board grabs the motion of internal anatomy through the fluoroscopy system, the computer acquires the organ motion tracking data by image processing without any additional physical markers. The patients breathe freely without any forced breath control and coaching, when this experiment was performed. The developed pattern-recognition software could extract the target motion signal in real-time from the acquired fluoroscopic images. The range of mean deviations between the real and acquired target positions was measured for some sample structures in an anatomical model phantom. The mean and max deviation between the real and acquired positions were less than 1mm and 2mm respectively with the standardized movement using a moving stage and an anatomical model phantom. Under the real human body, the mean and maximum distance of the peak to trough was measured 23.5mm and 55.1mm respectively for 13 patients' diaphragm motion. The acquired respiration profile showed that human expiration period was longer than the inspiration period. The above results could be applied to respiratory-gated radiotherapy.

• Progress in Medical Physics
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• v.23 no.2
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• pp.91-98
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• 2012

Verification of internal organ motion during treatment and its feedback is essential to accurate dose delivery to the moving target. We developed an offline based internal organ motion verification system (IMVS) using cine EPID images and evaluated its accuracy and availability through phantom study. For verification of organ motion using live cine EPID images, a pattern matching algorithm using an internal surrogate, which is very distinguishable and represents organ motion in the treatment field, like diaphragm, was employed in the self-developed analysis software. For the system performance test, we developed a linear motion phantom, which consists of a human body shaped phantom with a fake tumor in the lung, linear motion cart, and control software. The phantom was operated with a motion of 2 cm at 4 sec per cycle and cine EPID images were obtained at a rate of 3.3 and 6.6 frames per sec (2 MU/frame) with $1,024{\times}768$ pixel counts in a linear accelerator (10 MVX). Organ motion of the target was tracked using self-developed analysis software. Results were compared with planned data of the motion phantom and data from the video image based tracking system (RPM, Varian, USA) using an external surrogate in order to evaluate its accuracy. For quantitative analysis, we analyzed correlation between two data sets in terms of average cycle (peak to peak), amplitude, and pattern (RMS, root mean square) of motion. Averages for the cycle of motion from IMVS and RPM system were $3.98{\pm}0.11$ (IMVS 3.3 fps), $4.005{\pm}0.001$ (IMVS 6.6 fps), and $3.95{\pm}0.02$ (RPM), respectively, and showed good agreement on real value (4 sec/cycle). Average of the amplitude of motion tracked by our system showed $1.85{\pm}0.02$ cm (3.3 fps) and $1.94{\pm}0.02$ cm (6.6 fps) as showed a slightly different value, 0.15 (7.5% error) and 0.06 (3% error) cm, respectively, compared with the actual value (2 cm), due to time resolution for image acquisition. In analysis of pattern of motion, the value of the RMS from the cine EPID image in 3.3 fps (0.1044) grew slightly compared with data from 6.6 fps (0.0480). The organ motion verification system using sequential cine EPID images with an internal surrogate showed good representation of its motion within 3% error in a preliminary phantom study. The system can be implemented for clinical purposes, which include organ motion verification during treatment, compared with 4D treatment planning data, and its feedback for accurate dose delivery to the moving target.

• Journal of Pharmacopuncture
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• v.9 no.3 s.21
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• pp.5-10
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• 2006

Though anatomical and histological investigations on the novel threadlike and corpuscular structures, Bonghan duct(BHD) and Bonghan corpuscles(BHC) of internal organs of rats and rabbits were extensively studied. In this article we introduce the refined method to observe the BHD and BHC on the internal organs of mice. This development is needed because immunohistochemical analysis and other modern biological techniques were mostly applicable only to mice but not to rats and rabbits. We made uses of grazing effect of light as well as discriminating technique of BHD/C from fibrin and take the novel structures, BHD/C on mouse internal organ. The specimens taken were examined by hematoxyline and eosin(H & E) and revealed as novel structures. Our method described herein to take BHD/C characterization of mouse, especially for stem cell related researches.

• Tuberculosis and Respiratory Diseases
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• v.53 no.2
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• pp.234-237
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• 2002

A 77-year-old female was admitted 3 hours after intentionally ingesting 5g of aluminum ammonium sulfate ('Alum') powder dissolved in water. Gastric lavage with normal saline, activated charcoal chelation, and supportive therapies were performed. She showed a high anion gap metabolic acidosis, which rapidly progressed to multiple organ failure including ARDS. The patient subsequently progressed to a refractory shock which eventually led to death.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1098-1102
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• 1998

Sarcoidosis is a chronic multisystemic disorder of unknown cause characterized by presence of noncaseating epithelioid granuloma in affected organ. It is relatively common in western countries, but it is uncommon in East Asia including Korea. The lung is most frequently affected organ. Usual radiologic manifestation of thoracic sarcoidosis are readily recognized, but there are extremely diverse manifestation. Sarcoidosis rarely causes large pulmonary nodules, and cavitation in such lesion is very rare. We experienced one case of Sarcoidosis with Cavitary nodule of the lung and report it with brief review of the literature.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.170-181
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• 2017

The purpose of this study is to provide a more persuasive organ donation campaign based on the understanding of the public based on the personal characteristics and value factors of various age groups. The influence of personal characteristics and value factors (organ donation attitude, organ donation knowledge, self - efficacy, internal medicine, attitude toward discontinuation of life - saving treatment) on the intention of organ donation among 20s to 60s or older was examined. Demographic variables that were predicted to affect individual behavioral intentions such as gender, age, and religion were included. The value factors were also included attitudes toward life-sustaining treatment and afterlife view to identify potential factors. The results showed that attitude toward organ donation, knowledge of organ donation, self-efficacy, attitudes toward life-sustaining treatment had a significant positive effect on organ donation intention.

• Journal of Yeungnam Medical Science
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• v.33 no.2
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• pp.162-165
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• 2016

Barium sulfate is an inert material used as a radiographic contrast medium during upper gastrointestinal contrast studies for evaluation of patients with dysphagia. Oral barium aspiration is an uncommon but well-reported complication of this procedure. While barium aspiration of small amounts may not cause any symptoms, massive barium aspiration can be life-threatening, particularly in elderly patients with multiple comorbidities. In this case report, we describe an elderly patient with multiple comorbidities who presented with thyrotoxicosis and dysphagia, and then died after massive barium aspiration. Despite administration of intensive medical care with ventilator support and therapeutic bronchoalveolar lavage to remove the aspirated barium, the patient died of multiple organ failure 9 days after barium aspiration. Clinicians should pay attention to elderly patients with predisposing factors for aspiration in whom upper gastrointestinal barium contrast studies are indicated, and should consider other diagnostic tools for evaluation of dysphagia in this population.