• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.30-44
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• 1998

Accurate delivery of doses using a high dose rate(HDR) brachytherapy, remote afterloading system(RALS) depends on knowing the strength of the radioactive source at the time of treatment, the precision and consistency of the timer, and the ability of the unit to position the source at the proper dwell location along the applicator. Periodic Quality Assurance(QA) on HDR machines is a part of the standard protocol of any user. The safety of the patient & staff, positional accuracy, temporal accuracy, and dose delivery accuracy are periodically(weekly, quarterly, monthly) estimated using HDR source(Ir-192), treatment planning devices, measurement devices, and overall treatment devices with regard to treatment delivery. The overall measurement results are estimated successfully and assessed its clinical significance. As a result, our HDR brachytherapy units has been very accurate until now. The QA program protocol permits routine clinical use and provides a high confidence level in the accurate operation of HDR units. Therefore, regular QA of HDR brachytherapy is essential for successful treatment.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.163-170
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• 2018

This study was conducted to investigate the effects of noise from dental clinics on workers and to establish a reduction plan. The noise generated by the treatment instrument(Ultrasonic scaler, Hand piece, 3-way syringe, Suction, Compressor) was measured in order to determine the characteristics(level, frequency) of the noise during medical treatment(Oral prophylaxis, Conservation treatment, Prosthesis treatment, Implant Scaling, Tooth eliminating). We also assessed the noise levels in dental clinic using evaluation indicators such as NR-curves and NRN. The results of the analysis showed that the noise generated during the treatment was 85dB(A) ~ 70dB(A) and that the high frequency component was dominant, which would affect the workers working at the dental clinic. The NR-curve analysis showed NR-67 to NR-83 and the high frequency components of 4kHz to 8kHz were predominant and far exceeded noise levels in the workplace. To minimize the noise damage of workers and to provide high quality medical service, it is necessary to establish countermeasures such as wearing a soundproof and periodic hearing tests.

• Progress in Medical Physics
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• v.33 no.4
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• pp.37-52
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• 2022

Over the past decades, radiation therapy combined with imaging modalities that ensure optimal image guidance has revolutionized cancer treatment. The two major purposes of using imaging modalities in radiotherapy are to clearly delineate the target prior to treatment and set up the patient during radiation delivery. Image guidance secures target position prior to and during the treatment. High quality images provide an accurate definition of the treatment target and the possibility to reduce the treatment margin of the target volume, further lowering radiation toxicity and improving the quality of life of cancer patients. In this review, the various types of image guidance modalities used in radiation therapy are distinguished into ionized (kilovoltage and megavoltage image) and nonionized imaging (magnetic resonance image, ultrasound, surface imaging, and radiofrequency). The functional aspects, advantages, and limitation of imaging using these modalities are described as a subsection of each category. This review only focuses on the technological viewpoint of these modalities and any clinical aspects are omitted. Image guidance is essential, and its importance is rapidly increasing in modern radiotherapy. The most important aspect of using image guidance in clinical settings is to monitor the performance of image quality, which must be checked during the periodic quality assurance process.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.325-333
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• 2016

This study was conducted to provide the base line for the use of prophylactic antibiotics and the standard of antibiotic use and the evaluation based on analysis of current use, quality assessment and periodic changes of prophylactic antibiotics in a university hospital. We chose the year 2008, 2009, 2010, 2012, and 2014 as the study periods since the primary evaluation on the first year of implementation in 2007. For this study, healthcare benefit quality assessment data from the Health Insurance Review and Assessment Service was used. We analyzed the differences each year of treatment period; one category for initial treatment timing, three categories for selecting antibiotics, and two categories for the length of treatment from multiple evaluation indices of gastric surgeries, colorectal surgeries, and cholecystectomy. The analysis revealed the followings: Regarding length of antibiotics treatment, total days of treatment decreased down to 1.5, 1.5, and 0.6 days in the year 2014, from 13.5, 12.8, and 6.9 days in the year 2007, for gastric surgeries, colorectal surgeries, and cholecystectomy. Based on these outcomes, the efforts to devise efficient delivery and distribution of the recommendations or indices which medical staff could adhere for quality improvement of the prophylactic antibiotics would be necessary. Also implementing monitoring system to help the hospitals to acknowledge their own faults may be helpful.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1594-1600
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• 2011

Recently developed FDS5 CFD code has employed a near-wall flow treatment method which is Werner-Wengle wall law provided by NIST(National Institute of Standards and Technology). In this study, the wall law has been verified against DNS(Direct Numerical Simulation) data in the parallel plate. The $y^+$ was kept above 11 to fulfill the near-wall flow requirement in the grid generation. The total grid was $32{\times}32{\times}32$. The boundary condition for inlet and outlet was periodic condition and for both side, symmetric condition was used. The fully developed turbulent flow was generated and Re = 10,700. The simulated results were compared with DNS data. RANS results were also used for verification.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.390-395
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• 2013

Locoregional recurrence of tongue cancer is higher than that of other sites of the oral cavity. Locoregional control has shown improvement over the past 20 years, however, a high rate of recurrence and second primary tumor occurrence is still frequently reported. Leukoplakia is a clinical term, which describes a whitish lesion of the oral cavity. Clinicopathologic features may range from hyperkeratosis to malignancy. Because of its diverse pathologic characteristics, management of this lesion for diagnosis, treatment planning, establishment of a clear surgical margin, and periodic follow-up is difficult. We report on a case of successfully treated tongue cancer which developed from leukoplakia over 10 years. Periodic follow-up strategy and surgical planning are most important to management of locoregional recurrence.

• Korea-Australia Rheology Journal
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• v.11 no.3
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• pp.233-240
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• 1999

In order to understand the flow behavior of Electrorheological (ER) fluid, dynamic simulation has been intensively performed for the last decade. When the shear flow is applied, it is easy to carry out the simulation with relatively small number of particles because of the periodic boundary condition. For the squeezing flow, however, it is not easy to apply the periodic boundary condition, and the number of particles needs to be increased to simulate the ER system more realistically. For this reason, the simulation of ER fluid under squeezing flow has been mostly performed with some representative chains or with the approximation that severely restricts the flow geometry to reduce the computational load. In this study, Message Passing Interface (MPI), which is one of the most widely-used parallel processing techniques, has been employed in a dynamic simulation of ER fluid under squeezing flow. As the number of particles used in the simulation could be increased significantly, full domain between the electrodes has been covered. The numerical treatment or the approximation used to reduce the computational load has been evaluated for its validity, and was found to be quite effective. As the number of particles is increased, the fluctuation of the normal stress becomes diminished and the prediction in general was found to be qualitatively In good agreement with the experimental results.

• Advances in pediatric surgery
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• v.1 no.1
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• pp.53-58
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• 1995

A delayed primary esophago-esophagostomy of a case of long-gap esophageal atresia without tracheoesophageal fistula was performed in success with three months' intermittent periodic bougienage of the upper pouch via mouth as well as the lower esophagus through Janeway gastrostomy. Meanwhile, an effective continuous sump suction from the upper pouch seemed to be a critical part of the patient management. The extra length of esophagus for primary anastomosis could be achieved by a circular myotomy. Stricture at the myotomy site, found 4 months later, was treated with periodic pneumatic baloon dilations only with temporary symptomatic reliefs. After 4 months' trials, operative esophagoplasty was performed successfully. A careful follow-up schedule for the myotomy site would be required for early detection of stricture. The previous neonatal patient is currently 8 years old, healthy school-boy, and has a normal barium swallow without stricture or gastroesophageal reflux.

• Korean Membrane Journal
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• v.8 no.1
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• pp.50-57
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• 2006

We treated lake water by ceramic ultrafiltration membranes and found the optimal backflushing period and trans-membrane pressure (TMP) of periodic water-backflushing system. The optimal filtration time interval at fixed BT = 3 sec was 30 for A002 membrane in all viewpoints of $J/J_0,\;R_f$, and $V_T$, and we could acquire the highest $V_T$ value in the membranes used here. However, the highest $V_T$ was acquired at FT = 60 sec for M9, and at FT = 90 sec for C005 membrane. Then the lower TMP reduced the membrane fouling during filtration of lake water, and could maintain the higher permeate flux compared with the initial flux. However, the largest value $V_T$ could be obtained at the highest TMP condition for M9 membrane at fixed FT = 60 sec and BT = 3 sec. The quality of treated water in our UF ceramic system was Turbidity = $0.20{\sim}4.88NTU$, $COD_{Mn} = 0.00{\sim}2.58 mg/L$, $TDS = l8{\sim}71 mg/L$, and $NH_3-N = 0.004{\sim}1.689 mg/L$.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.228-236
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• 1999

Background: Thyrotoxic periodic paralysis is an uncommon illness characterized by intermittent flaccid paralysis of skeletal muscle, usually accompanied by hypokalemia, in patient with hyperthyroidism. However, the pathophysiology of thyrotoxic periodic paralysis remains largely unexplained and controversial. This report describes the clinical and biochemical findings in 19 patients with thyrotoxic periodic paralysis who were examined at the Yeungnam University Medical Center(YUMC) during the past decade. Methods: The medical records of 997 YUMC patients, seen between 1986 and 1996, with diagnosis of hyperthyroidism were reviewed. Nineteen patients out of 997 hyperthyroidism patients were diagnosed, and examined by history, physical examination, serum electrolyte value, and thyroid function test during paralysis. On the basis of these results, comparisons were made on age, sex, precipitating factors, timing, affected limbs, prognosis, serum potassium and serum phosphate and thyroid hormone levels. Results: The prevalence of periodic paralysis in hyperthyroidism was 1.9 percent and the male to female prevalence ratio was 30:1 and in all patients, the development of perodic paralysis was correlated with hyperfunctional state of the thyroid gland. Eleven cases of periodic paralysis were associated with hypokalemia and their thyroid hormone levels were significantly more increased than those of the patients without hypokalemia. Interestingly, our study shows the recurrence of paralysis after treatment. Conclusion: Although the precise pathophysiology of the disease is as yet undefined and controversial, it occurs primarily in Asians with an overwhelming male preponderance and prevalence of 2 percent in hyperthyroidism. The interactive roles of thyroid hormone, Na-K pump, and genetically inherited defect in the cellular membrane potential of the skeletal muscle can be speculated. Further investigation will be needed to firmly establish the mechanism of thyrotoxic periodic paralysis.