• Radiation Oncology Journal
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• v.36 no.1
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• pp.54-62
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• 2018

Purpose: To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). Methods: We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3-5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (${\Sigma}$) and random (${\sigma}$) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula ($2.5{\Sigma}+0.7r$). Results: The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0-9 mm in ML direction, 0-5 mm in SI direction and 0-10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. Conclusion: Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3-5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.333-338
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• 2013

Purpose: A growing number of studies have been providing evidence for neural connections between the auditory and somatosensory systems that might be a critical part of the mechanisms underlying certain forms of tinnitus. The aim of this study was to investigate the effect of temporomandibular joint (TMJ) movements on tinnitus. Methods: One hundred sixty-three tinnitus patients participated in this study. All patients underwent a thorough audiological examination including pure-tone audiometry, tinnitus handicap inventory, and evaluation of tinnitus loudness, frequency and severity on a visual analog scale. Somatic testing consisting of nine forceful jaw muscle contractions was performed to evaluate the effect of TMJ movements on modulation of tinnitus. Results: 66.9% of patients had unilateral tinnitus. Somatic testing modulated tinnitus loudness in 125 ears (57.6 %) of 217 ears tested. An increase in tinnitus loudness was observed more often than a decrease. Loudness was most commonly increased by opening and clenching jaw. Tinnitus could be induced by opening, clenching and deviating jaw to the left. Conclusion: Our study showed evidence that TMJ movements may aggravate and even evoke tinnitus and somatic testing can be used for evaluating if stimulation of the TMJ induces or aggravates tinnitus.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.435-445
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• 2022

In this study, the reverberation of a bistatic sonar operated in southeastern coast in the East Sea in July 2020 was analyzed. The reverberation sensor data were collected through an LFM sound source towed by a research vessel and a horizontal line array receiver 1 km to 5 km away from it. The reverberation sensor data was analyzed by various methods including geo-plot after signal processing. Through this, it was confirmed that the angle reflected from the sound source through the scatterer to the receiver has a dominant influence on the distribution of the reverberation sound, and the probability distribution characteristics of bistatic sonar reverberation varies for each beam. In addition, parametric factors of K distribution and Rayleigh distribution were estimated from the sample through moment method estimation. Using the Kolmogorov-Smirnov test at the confidence level of 0.05, the distribution probability of the data was analyzed. As a result, it could be observed that the reverberation follows a Rayleigh probability distribution, and it could be estimated that this was the effect of a low reverberation to noise ratio.

• Child Health Nursing Research
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• v.4 no.2
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• pp.159-176
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• 1998

In effort to conduct comparative study on the caregiving environment of Neonatal Intensive Care Unit(NICU) in both U. S and Korea, this study was been conducted first in the U.S. Purpose : The purpose of this study is to identify the physical environment and direct caregiving practices to lowbirth weight infants in NICU in the US. It also aims to examine the NICU outcome status and behavioral reponses of lowbirth weight infants. Methods : A study design using descriptive and inferential statistics was been conducted through an observational, field method. A sample of 15 preform infants admitted to NICU were recruited for the study. The subjects were those with birth weight between 1,000 gm to 1,500 gm, born at the gestation period of 27 to 33 weeks, and without any chromosomal or other genetic anomalies, major congenital infections, or maternal illness. Thirty minutes observation(three times of ten minutes of continuous observation)of the infant's behavior and physiological status, and an four-hour observation of the physical environment and direct care giving procedures were been conducted on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. The data to be collected were in four areas : the demograghic characteristics of the infants, the physical environment and care giving procedures, the frequency of the infant's designated behavior and physiological response, and NICU outcome variables. A descriptive analysis and Kruskal-Wallis, Pearson r were been applied according to variable characteristics. Results : 1. Mother's mean age was 29.47. The sample consisted of 6 males and 9 females. Mean gestational ages were 29.17 weeks. Mean birth weight was 1236.33g. Mean Apgar scores at one minute were 6.6, and 7.8 at five minutes. 2. The location for the incubator was in the distance from the light, X-ray screens and nursing station, in proximity to side-lamp, telephone and faucet on the third day after birth. The location for the incubator was in the distance from the light and radio on the tenth day and in proximity to nursing station on the day of dischage from the NICU or at 34weeks postconception. 3. Nesting was the most applying aids to the infants. And foot roll, shielding and plastic frame were frequently using by nurses for facilitating well modulated restful posture. 4. There were statistically significant changes in the patterns of physical environment included locating the infant's incubator and bedding, specific aids to self regulation on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. 5. Statistically significant changes were not appeared in the patterns of direct caregiving procedure to the infants included stress inducing or reducing manipulations on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. 6. The stress response of the infants in NICU were significantly reduced as the infants grow older. 7. There were not statistically significant correlation between the physical envronment and the stress responses of the infants in NICU. 8. There were statistically significant correlation between the direct caregiving procedure to the infants and the stress response of the infants in NICU in the second and third observation on the day three. 9. Average weight gain per day from birth to discharge was 38.73g, number of days in the hospital was 42.60, number of days before bottle feeding was 3.6. Postconception age starting bottle feed ing was 31/sup +5/ weeks. Number of days on mechanical ventilator was average 7.64, 11.42 was an average number of days of oxygen need. Conclusion : It, thus, appears that to minimize the sensorymotor stimulation for the low birthweight preterm infant in NICU, manipulation of care giving practices to the babies whatever the stress inducing or reducing procedures, have to be limited in the immediate early stage after birth. And it needed to be reexamine to identify the appropriate and specific physical environment and the patterns of direct caregiving to the low birthweight preform infant as the infants grow older in NICU.

• Progress in Medical Physics
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• v.26 no.4
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• pp.294-303
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• 2015

American Association of Physicists in Medicine (AAPM) Published Task Group 40 report which includes recommendations for comprehensive quality assurance (QA) for medical linear accelerator in 1994 and TG-142 report for recommendation for QA which includes procedures such as intensity-modulated radiotherapy (IMRT), stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) in 2010. Recently, Nuclear Safety and Security Commission (NSSC) published NSSC notification no. 2015-005 which is "Technological standards for radiation safety of medical field". This notification regulate to establish guidelines for quality assurance which includes organization and job, devices, methods/frequency/tolerances and action levels for QA, and to implement quality assurance in each medical institution. For this reason, all of these facilities using medical machine for patient treatment should establish items, frequencies and tolerances for proper QA for medical treatment machine that use the techniques such as non-IMRT, IMRT and SRS/SBRT, and perform quality assurance. For domestic, however, there are lack of guidelines and reports of Korean Society of Medical Physicists (KSMP) for reference to establish systematic QA report in medical institutes. This report, therefore, suggested comprehensive quality assurance system such as the scheme of quality assurance system, which is considered for domestic conditions, based the notification of NSSC and AAPM TG-142 reports. We think that the quality assurance system suggested for medical linear accelerator also help establishing QA system for another high-precision radiation treatment machines.