• Radiation Oncology Journal
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• v.19 no.4
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• pp.319-326
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• 2001

Purpose : Planning target volume (PTV) for tumors in abdomen or thorax includes enough margin for breathing-related movement of tumor volumes during treatment. Depending on the location of the tumor, the magnitude of PTV margin extends from 10 mm to 30 mm, which increases substantial volume of the irradiated normal tissue hence, resulting in increase of normal tissue complication probability (NTCP). We developed a simple and handy method which can reduce PTV margins in patients with liver tumors, respiratory motion reduction device (RRD). Materials and methods : For 10 liver cancer patients, the data of internal organ motion were obtained by examining the diaphragm motion under fluoroscope. It was tested for both supine and prone position. A RRD was made using MeV-Green and Styrofoam panels and then applied to the patients. By analyzing the diaphragm movement from patients with RRD, the magnitude of PTV margin was determined and dose volume histogram (DVH) was computed using AcQ-Plan, a treatment planning software. Dose to normal tissue between patients with RRD and without RRD was analyzed by comparing the fraction of the normal liver receiving to $50\%$ of the isocenter dose. DVH and NTCP for normal liver and adjacent organs were also evaluated. Results : When patients breathed freely, average movement of diaphragm was $12{\pm}1.9\;mm$ in prone position in contrast to $16{\pm}1.9\;mm$ in supine position. In prone position, difference in diaphragm movement with and without RRD was $3{\pm}0.9\;mm$ and 12 mm, respectively, showing that PTV margins could be reduced to as much as 9 mm. With RRD, volume of the irradiated normal liver reduced up to $22.7\%$ in DVH analysis. Conclusion : Internal organ motion due to breathing can be reduced using RRD, which is simple and easy to use in clinical setting. It can reduce the organ motion-related PTV margin, thereby decrease volume of the irradiated normal tissue.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.244-252
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• 2014

Purpose : We proposed a multi-physiological signals based real-time intelligent triggering system(MITS) for Cardiac MRI. Induced noise of the system was analyzed. Materials and Methods: MITS makes cardiac MR imaging sequence synchronize to the cardiac motion using ECG, respiratory signal and second order derivative of $SPO_2$signal. Abnormal peaks due to arrhythmia or subject's motion are rejected using the average R-R intervals and R-peak values. Induced eddy currents by gradients switching in cardiac MR imaging are analyzed. The induced eddy currents were removed by hardware and software filters. Results: Cardiac MR images that synchronized to the cardiac and respiratory motion are acquired using MITS successfully without artifacts caused by induced eddy currents of gradient switching or subject's motion or arrhythmia. We showed that the second order derivative of the $SPO_2$ signal can be used as a complement to the ECG signals. Conclusion: The proposed system performs cardiac and respiratory gating with multi-physiological signals in real time. During the cardiac gating, induced noise caused by eddy currents is removed. False triggers due to subject's motion or arrhythmia are rejected. The cardiac MR imaging with free breathing is obtained using MITS.

• Journal of radiological science and technology
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• v.33 no.4
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• pp.379-386
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• 2010

This study evaluated the motion of tumors during the entire period of therapy and the accuracy of radiosurgery among forty eight lung tumor patients who were underwent radiosurgery using the CyberKnife Synchrony Respiratory Tracking System. The motion of lung tumor was measured by the coordinates of a gold acupuncture needle inserted into the tumor or the area around the tumor using the CyberKnife image guided system. Then the accuracy of radiosurgery was evaluated based on the error of correlation computed with the motion tracking system. The lung tumor motion is Cranio-Caudal direction by an average of $2.63{\pm}1.87\;mm$, moved left-right direction by $1.13{\pm}0.71\;mm$, and anterior-posterior direction by $1.74{\pm}1.16\;mm$. The degree of rotational movement was $1.66{\pm}1.66^{\circ}$ on X axis, $1.20{\pm}0.97^{\circ}$ on Y axis, and $1.18{\pm}0.73^{\circ}$ on Z axis. The vector of translation movement was measured to be $3.78{\pm}2.00\;mm$ on the average. The results show that directions of Cranio-Caudal(p < 0.001), anterior-posterior direction(p < 0.029), and three dimensional vector value(p < 0.002) showed statistical significance, because the lower side of tumor showed more intensive movement compared to the upper side of tumor. The radiosurgery was carried out by compensating the motion of tumor after accurate investigation of the correlation error with the average of $0.95{\pm}0.62\;mm$ during the lung tumor radiosurgery with the CyberKnife Synchrony Respiratory Tracking System.

• Journal of Radiation Protection and Research
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• v.44 no.3
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• pp.103-109
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• 2019

Background: Four-dimensional computed tomographic (4DCT) images are increasingly used in clinic with the growing need to account for the respiratory motion of the patient during radiation treatment. One of the reason s that makes the dose evaluation using 4DCT inaccurate is a change of the patient respiration during the treatment session, i.e., intrafractional uncertainty. Especially, when the amplitude of the patient respiration is greater than the respiration range during the 4DCT acquisition, such an organ motion from the larger respiration is difficult to be represented with the 4DCT. In this paper, the method to generate images expecting the organ motion from a respiration with extended amplitude was proposed and examined. Materials and Methods: We propose a method to generate extra-phase images from a given set of the 4DCT images using deformable image registration (DIR) and linear extrapolation. Deformation vector fields (DVF) are calculated from the given set of images, then extrapolated according to respiratory surrogate. The extra-phase images are generated by applying the extrapolated DVFs to the existing 4DCT images. The proposed method was tested with the 4DCT of a physical 4D phantom. Results and Discussion: The tumor position in the generated extra-phase image was in a good agreement with that in the gold-standard image which is separately acquired, using the same 4DCT machine, with a larger range of respiration. It was also found that we can generate the best quality extra-phase image by using the maximum inhalation phase (T0) and maximum exhalation phase (T50) images for extrapolation. Conclusion: In the present study, a method to construct extra-phase images that represent expanded respiratory motion of the patient has been proposed and tested. The movement of organs from a larger respiration amplitude can be predicted by the proposed method. We believe the method may be utilized for realistic simulation of radiation therapy.

• Progress in Medical Physics
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• v.22 no.3
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• pp.107-116
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• 2011

Respiratory gated radiation therapy and stereotactic body radiation therapy require identical tumor motions during each treatment with the motion detected in treatment planning CT. Therefore, this study developed a tumor motion monitoring and analysis system during the treatments employing RPM data, gated setup OBI images and a data analysis software. A respiratory training and guiding program which improves the regularity of breathing was used to patients. The breathing signal was obtained by RPM and the recorded data in the 4D console was read after treatment. The setup OBI images obtained gated at 0% and 50% of breathing phases were used to detect the tumor motion range in crenio-caudal direction. By matching the RPM data recorded at the OBI imaging time, a factor which converts the RPM motion to the tumor motion was computed. RPM data was entered to the institute developed data analysis software and the maximum, minimum, average of the breathing motion as well as the standard deviation of motion amplitude and period was computed. The computed result is exported in an excel file. The conversion factor was applied to the analyzed data to estimate the tumor motion. The accuracy of the developed method was tested by using a moving phantom, and the efficacy was evaluated for 10 stereotactic body radiation therapy patients. For the sine wave motion of the phantom with 4 sec of period and 2 cm of peak-to-peak amplitude, the measurement was slightly larger (4.052 sec) and the amplitude was smaller (1.952 cm). For patient treatment, one patient was evaluated not to qualified to SBRT due to the usability of the breathing, and in one patient case, the treatment was changed to respiratory gated treatment due the larger motion range of the tumor than treatment planed motion. The developed method and data analysis program was useful to estimate the tumor motion during treatment.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.125-131
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• 2005

Purpose : For stereotactic radiosurgery (SRS) of a tumor in the region whose movement due to respiration is significant, like Lung lower lobe, the gated therapy, which delivers radiation dose to the selected respiratory phases when tumor motion is small, was performed using the Respiratory gating system and its clinical effectiveness was evaluated. Materials and Methods : For two SRS patients with a tumor in Lung lower lobe, a marker block (infrared reflector) was attached on the abdomen. While patient' respiratory cycle was monitored with Real-time Position Management (RPM, Varian, USA), 4D CT was performed (10 phases per a cycle). Phases in which tumor motion did not change rapidly were decided as treatment phases. The treatment volume was contoured on the CT images for selected treatment phases using maximum intensity projection (MIP) method. In order to verify setup reproducibility and positional variation, 4D CT was repeated. Results : Gross tumor volume (GTV) showed maximum movement in superior-inferior direction. For patient #1, motion of GTV was reduced to 2.6 mm in treatment phases ($30{\sim}60%$), while that was 9.4 mm in full phases ($0{\sim}90%$) and for patient #2, it was reduced to 2.3 mm in treatment phases ($30{\sim}70%$), while it was 11.7 mm in full phases ($0{\sim}90%$). When comparing two sets of CT images, setup errors in all the directions were within 3 mm. Conclusion : Since tumor motion was reduced less than 5 mm, the Respiratory gating system for SRS of Lung lower lobe is useful.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.2
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• pp.75-87
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• 2010

Objectives Halitosis affects a large proportion of the population, and it may cause a significant social or psychological problems but pathophysiological mechanism of halitosis is unclear. The purpose of this study is to investigate pediatric halitosis patients' characteristics and their related symptoms. Methods 133 patients were participated at the Pediatric Clinic of Kyanhee Oriental Medical Center from May 29th, 2010 to July 10th, 2010. We measured sulfide level and reviewed medical charts and asked some questions. Patients of sex, age, respiratory symptoms, digestive symptoms, systemic symptoms and sulfide level were analyzed. Results Stuffy nose, cough after sleep, sputum, snoring, indigestion, stomachache, motion sickness, and Bi-We-Soo diagnosis grades were significantly associated with halitosis Conclusions Based on data, we found that halitosis is related to the respiratory and digestive symptoms. Also, we can refer this study when diagnosing patients or giving treatments to patients.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.353-356
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• 1993

Advent of new imaging modalities such as computed tomography, magnetic resonance imaging and ultrasound contributed greately to the specific imaging diagnosis. However plain chest X-ray is still most prequently used for imaging diagnosis of respiratory disease in clinical pratic and it is important to make a good quality of X-ray film and good interpretation. The optimal chest X-ray should be taken with full inspiration without rotation and motion and the exposure is at the level of barely demonstrable thoracic vertebral disc space. It is recommended that higk KVP technique for detection of lesions which is overlaped by mediastinum, heart and rib cage. It is better to examine chest X-ray film start at some distance(6-8 feet) and closer to the film later on and the reader should not read a film in fatigue condition. The reading room should be quiet and relately dark illumination. It is important, to make a good X-ray film and good interpretation to reduce the observer error.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.116-116
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• 2006

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.28-28
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• 2006