• Journal of radiological science and technology
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• v.42 no.2
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• pp.137-143
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• 2019

The aim of this study was analyzed the setup error of breast cancer patients in intensity modulated radiation therapy(IMRT) with deep inspiration breath holding(DIBH) and was analyzed the dose distribution due to setup error. A total of 45 breast cancer cases were performed a retrospective clinical analysis of setup error. In addition, the re-treatment planning was carried by shifting the setup error from the isocenter at the treatment. Based on this, the dose distribution of PTV and OARs was compared and analyzed. The 3D error for small breast group and medium breast group and large breast group were 3.1 mm and 3.7 mm and 4.1 mm, respectively. The difference between the groups was statistically significant(P=0.003). DVH results showed HI, CI for the PTV difference between standard treatment plan and re-treatment plan of 14.4%, 4%. The difference in $D_5$ and $V_{20}$ of the ipsilateral lung was 5.6%, 13% respectively. The difference in $D_5$ and $V_5$ of the heart of right breast cancer patients was 6.8%, 8% respectively. The difference in $D_5$, $V_{20}$ of the heart of left breast cancer patients was 7.2%, 23.5% respectively. In this study, there was a significant association between breast size and significant setup error in breast cancer patients with DIBH. In addition, it was found that the dose distribution of the PTV and OARs varied according to the setup error.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.57-57
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• 2006

• Annals of Clinical Neurophysiology
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• v.6 no.1
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• pp.43-47
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• 2004

We report a case of 36-year-old woman with myasthenia gravis (MG) combined with mediastinal leiomyosarcoma (LMS) and Stevens-Johnson syndrome (SJS). She was admitted to ICU with the symptoms of acute onset headache, diplopia, ptosis, dysphagia, general weakness, and respiratory difficulty for several days. Physical examination revealed tachypnea, decreased breath sounds and dullness to percussion in right lower chest. Neurologic examination showed ptosis, diplopia, decreased gag reflexes, and generalized proximal weakness. Laboratory studies revealed increased serum acetylcholine receptor antibodies and positive Tensilon test. Chest CT showed a huge mass in the right middle mediastium but no evidence of thymic enlargement. Mediastinal LMS was diagnosed by ultrasound-guided needle biopsy. The myasthenic symptoms were fluctuated in spite og intravenous immunoglobulin, plasmapheresis, and corticosteroid. During therapy, SJS developed. She died 4 months after the onset of the myasthenic symptoms despite the chemotherapy for LMS.

• Radiation Oncology Journal
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• v.26 no.3
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• pp.181-188
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• 2008

Purpose: In order to enhance the efficiency of respiratory gated 4-dimensional radiation therapy for more regular and stable respiratory period and amplitude, a respiration training system was designed, and its efficacy was evaluated. Materials and Methods: The experiment was designed to measure the difference in respiration regularity following the use of a training system. A total of 11 subjects (9 volunteers and 2 patients) were included in the experiments. Three different breathing signals, including free breathing (free-breathing), guided breathing that followed training software (guided-breathing), and free breathing after the guided-breathing (post guided-breathing), were consecutively recorded in each subject. The peak-to-peak (PTP) period of the breathing signal, standard deviation (SD), peak-amplitude and its SD, area of the one cycle of the breathing wave form, and its root mean square (RMS) were measured and computed. Results: The temporal regularity was significantly improved in guided-breathing since the SD of breathing period reduced (free-breathing 0.568 vs guided-breathing 0.344, p=0.0013). The SD of the breathing period representing the post guided-breathing was also reduced, but the difference was not statistically significant (free-breathing 0.568 vs. guided-breathing 0.512, p=ns). Also the SD of measured amplitude was reduced in guided-breathing (free-breathing 1.317 vs. guided-breathing 1.068, p=0.187), although not significant. This indicated that the tidal volume for each breath was kept more even in guided-breathing compared to free-breathing. There was no change in breathing pattern between free-breathing and guided-breathing. The average area of breathing wave form and its RMS in postguided-breathing, however, was reduced by 7% and 5.9%, respectively. Conclusion: The guided-breathing was more stable and regular than the other forms of breathing data. Therefore, the developed respiratory training system was effective in improving the temporal regularity and maintaining a more even tidal volume.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.794-798
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• 2018

There is a growing need for a care system that can continuously monitor, manage and effectively relieve stress for modern people. In recent years, mobile healthcare devices capable of measuring heart rate have become popular, and many stress monitoring techniques using heart rate variability analysis have been actively proposed and commercialized. In addition, respiratory biofeedback methods are used to provide stress relieving services in environments using mobile healthcare devices. In this case, breathing information should be measured well to assess whether the user is doing well in biofeedback training. In this study, we extracted the heart beat interval signal from the PPG and used the oscillator based notch filter based on the IIR band pass filter to track the strongest frequency in the heart beat interval signal. The respiration signal was then estimated by filtering the heart beat interval signal with this frequency as the center frequency. Experimental results showed that the number of breathing could be measured accurately when the subject was guided to take a deep breath. Also, in the timeing measurement of inspiration and expiration, a time delay of about 1 second occurred. It is expected that this will provide a respiratory biofeedback service that can assess whether or not breathing exercise are performed well.

• Journal of Korean society of Dental Hygiene
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• v.23 no.6
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• pp.529-536
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• 2023

Objectives: This study aimed to determine the relationship between hours of smartphone use and oral disease symptoms in Korean adolescents. Methods: In this study, data from the 2022 Youth Health Behavior Online Survey were used. The final analysis was conducted on students who responded that they have used a smartphone (N=50,375). Chi-squared test and multivariate logistic regression analysis were used to analyze the relationship between oral disease symptoms and smartphone use time (p<0.05). Results: Consequent to examining the effect of smartphone use on oral disease symptoms, it was found that oral symptoms, such as pain during chewing and tingling throbbing, increased as smartphones were used for >4 h (p<0.05). Additionally, oral symptoms, such as gingivalgia bleeding and bad breath, appeared to increase as smartphones were used for >6 h (p<0.05). However, using smartphones for <0-2 h or 2-4 h had no effect on oral disease symptoms. Conclusions: In adolescents, oral disease symptoms increased significantly with increasing hours of smartphone use. Therefore, adolescents should be guided so that they use smartphones for <2 h or >4 h. Moreover, guidance on forming the habit of tooth brushing after eating food should be provided to prevent oral disease symptoms.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.250-255
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• 2015

Purpose: To compare audio-only biofeedback to conventional audiovisual biofeedback for regulating patients' respiration during four-dimensional radiotherapy, limiting damage to healthy surrounding tissues caused by organ movement. Materials and Methods: Six healthy volunteers were assisted by audiovisual or audio-only biofeedback systems to regulate their respirations. Volunteers breathed through a mask developed for this study by following computer-generated guiding curves displayed on a screen, combined with instructional sounds. They then performed breathing following instructional sounds only. The guiding signals and the volunteers' respiratory signals were logged at 20 samples per second. Results: The standard deviations between the guiding and respiratory curves for the audiovisual and audio-only biofeedback systems were 21.55% and 23.19%, respectively; the average correlation coefficients were 0.9778 and 0.9756, respectively. The regularities between audiovisual and audio-only biofeedback for six volunteers' respirations were same statistically from the paired t-test. Conclusion: The difference between the audiovisual and audio-only biofeedback methods was not significant. Audio-only biofeedback has many advantages, as patients do not require a mask and can quickly adapt to this method in the clinic.

• Tuberculosis and Respiratory Diseases
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• v.69 no.4
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• pp.293-297
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• 2010

A 60-year-old man was diagnosed with stage IV squamous cell carcinoma of lung and treated with weekly doses of docetaxel and cisplatin. Tumor mass and mediastinal lymphadenopathy disappeared after 4.5 cycles of chemotherapy. At one week post final chemotherapy, the patients developed sudden shortness of breath. New, multifocal infiltrations developed on both lungs without definitive evidence of infection. Despite administration of broad spectrum antibiotics, the lung lesion did not improve, so bronchoalveolar lavage and computed tomography-guided lung biopsy were performed. The proportion of lymphocytes was increased markedly and histopathology revealed squamous cell carcinoma combined with bronchiolitis obliterans organizing pneumonia. After high dose corticosteroid therapy, dyspnea and the newly developed consolidation had decreased slightly. However, dyspnea and hypoxemia increased again because of aggravated lung cancer since chemotherapy had stopped. Chemotherapy couldn't be restarted due to the poor performance status of the patient. Later, patient died of respiratory failure from poor general condition and progression of lung cancer.

• 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.15 no.4
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• pp.179-185
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• 2004

To deal with tumor motion from respiration is one of the important issues for the advanced treatment techniques, such as the intensity modulated radiation therapy (IMRT), the image guided radiation therapy (IGRT), the three dimensional conformal therapy (3D-CRT) and the Cyber Knife. Studies including the active breath control (ABC) and the gated radiation therapy have been reported. Authors have developed the device for reducing the respiration effects and the diaphragm motions with this device were observed to determined the effectiveness of the device. The device consists of four belts to immobilize diaphragm motion and the vacuum cushion. Diaphragm motions without and with device were monitored fluoroscopically. Diaphragm motion ranges were found to be 1.14 ～ 3.14 cm (average 2.14 cm) without the device and 0.72～1.95 cm (average 1.16 cm) with the device. The motion ranges were decreased 20 ～ 68.4% (average 44.9%.) However, the respiration cycle was increased from 4.4 seconds to 3.7 seconds. The CTV-PTV margin could be decreased significantly with the device developed in this study, which may be applied to the treatments of the tumor sited diaphragm region.