• Radiation Oncology Journal
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• v.11 no.1
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• pp.79-82
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• 1993

From October 1989 to March 1992, ten patients diagnosed as primary central nervous system (CNS) lymphoma were treated with radiation therapy at Asan Medical Center. To obtain pathologic diagnosis, five patients had stereotactic biopsy and the others underwent craniotomy & tumor removal. According to the classification by International Working Formulation, seven of 10 patients showed diffuse large cell types and the remaining 3 had diffuse mixed cell types. Computed tomographic scans of the brain disclosed solitary (6 cases) or multiple (4 cases) intracranial lesions. All patients received 4000 cGy/20 fx to the whole brain followed by an additional 2000 cGy/10 fx boost to the primary lesion. Six patients with initial cerebrospinal fluid (CSF involvement were treated with whole brain irradiation and intrathecal Methotrexate (IT-MTX) chemotherapy. One of them received an additional spinal irradiation after 3 cycles of IT-MTX chemotherapy because of MTX induced arachnoiditis. One patient received 3 cycles of systemic chemotherapy prior to rodiation therapy and one received 5 cycles of salvage chemotherapy for recurrence. With a median follow up time of 8 months, all patients were followed from 7 to 26 months. Radiologically seven patients showed complete remission and the remaining three showed partial remission at one month after radiotherapy. The 1 and 2 year survival rate was $86{\%}\;and\;69{\%}$ respectively. Until now, two patients expired at 7 and 14 months. These patients developed extensive CSF seeding followed by local failure. Considering initial good response to radiation therapy and low incidence of extraneural dissemination in primary CNS lymphoma, we propose to increase total tumor dose to the primary lesion by hyperfractionated radiotherapy or stereotactic radiosurgery. For the patients with CSF involvement at diagnosis, we propose craniospinal irradiation with IT MTX chemotherapy.

• Radiation Oncology Journal
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• v.27 no.3
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• pp.120-125
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• 2009

Purpose: We wanted to present the preliminary results of intensity-modulated radiotherapy (IMRT) for the treatment of tonsillar cancer. Materials and Methods: We retrospectively analyzed 12 patients who underwent IMRT for tonsillar cancer at Asan Medical Center between November 2002 and February 2007. Seven patients (58%) received definitive treatment, and five (42%) were treated in the postoperative setting. Among the definitively treated patients, 6 patients received cisplatin-based chemotherapy regimens. Simultaneous modulated accelerated radiation therapy (SMART) was used in nine patients. The prescribed dose was 72 Gy at 2.4 Gy/fraction for the definitively treated cases and 61.6 Gy at 2.2 Gy/fraction for the postoperative cases. The median follow-up period was 34 months. Results: All twelve patients completed treatment without interruption, and eleven showed a complete response. One patient had persistent loco-regional disease after treatment. The three-year estimates of loco-regional control, disease-free survival and overall survival were 91.7%, 91.7%, and 100%. The worst acute mucositis was Grade 1 in four patients, Grade 2 in five patients, Grade 3 in two patients and Grade 4 in one patient. Grade 3 xerostomia was observed in six patients. Conclusion: Intensity-modulated radiotherapy was shown to be a safe and effective treatment modality for tonsillar cancer. Further studies with a larger number of patients and a longer follow-up period are needed to evaluate the ultimate tumor control and late toxicity of IMRT for treating tonsillar cancer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.1
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• pp.13-26
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• 2001

Six ferromanganese crusts from the Lomilik and Litatfooki seamounts in the Marshall Islands were analyzed for texture, geochemistry and stratigraphy to delineate the paleoceanographic conditions. The crusts can be divided into three layers; 1) outermost massive layer (Layer 1), 2) middle porous Fe-oxides rich layer infllled with biointemal clasts (Layer 2), and 3) innermost massive layer cemented and/or replaced by carbonate fluoapatite (CFA) (Layer 3). The Layer 1 contains higher Mn, Co, Ni, and Mg than other two layers, and the Layer 2 was relatively more enriched in Fe, Al, Ti, Ba, Cu, and Zn. However, the Layer 3 shows higher Ca and P and lower Mn, Fe, Co, and Ni contents than overlying two layers. Based on the Co-chronometry, the crusts are postulated to have begun to grow from 56-31 Ma (early Eocene to Oligocene). The boundaries between layers 1 and 2, and layers 2 and 3 are dated to be 7-3 Ma and 26-14 Ma, respectively. High contents of Ca and P in Layer 3 clearly indicate that the layer had been phosphatized prior to the formation of Layer 2. Considering the well-preserved mjcrostructures in Layer 3, it is unlike that the crusts themselves were recrystallized in suboxic condition. Also, the lower Co concentrations in Layer 3 may imply that the Co supply was not constant during the formation of Layer 3. Layer 2, characterized by the porous texture, grew over Layer 3 during 26-9 Ma. Internal biogenic sediments including foraminifera within the original cavities and the enrichment of organophillic elements such as Ba, Cu, and Zn, suggest that Layer 2 have below high production regions. Also, high content of allumino silicate components may indicate increased terrigeneous input during the formation of Layer 2. The Layer 2. The Layer 1 has been subjected to little diagenetic influence since the Pliocene.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.267-272
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• 2003

Background: Common treatment modalities for tracheal stenosis include conservative methods such as repeated balloon dilatation, removal of obstructive material through bronchoscopy and T-tube insertion as well as operative treatment methods. Recent advances in surgical approaches through tracheal resection and end-to-end anastomosis have been reported to give better functional and anatomical results. Material and Method: Between March 1990 and July 2002, 41 patients who received tracheal resection and end-to-end anastomosis at Asan Medical Center, University of Ulsan were studied retrospectively. Result: The causes for tracheal resection and end-to-end anastomosis included 26 cases of postintubation stenosis, 10 cases of primary tracheal tumors (3 benign, 7 malignant), 1 case of endobronchial tuberculosis, 2 cases of traumatic rupture, and 2 cases of tracheal invasion of a thyroid cancer, Of the 41 patients who received tracheal resection and reconstruction, 29 received tracheal resection and end-to-end anastomosis, and 12 received laryngotracheal anastomosis with cricoid or thyroid cartilage resection. Four of these patients received supralaryngeal release. The average length of the resected trachea was $3.6{\pm}1.0$cm. Of the 41 patients who received tracheal resection and end-to-end anastomosis, 30 (73.2%) experienced no postoperative complications, and 8 (19.5%) experienced granulation tissue growth and/or minor infections which improved after conservative management. Good or satisfactory results were therefore achieved in 92.7%. Complications included repeated granulation tissue growth in 7, wound infection in 2, anastomotic site dehiscence in 2, restenosis resulting in dyspnea on exertion in 1, and repeated postoperative aspiration requiring retracheostomy in 1. There was no early postoperative mortality. There were 3 cases of hospital death. Conclusion: In cases of proper length of tracheal lesion, excellent results were obtained after tracheal resection and end-to-end anastomosis. But, granulation tissue growth is so serious complication, it is necessary for continuous study and efforts to prevent it.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.70-74
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• 2011

Purpose: In the Nuclear Medicine department of Asan Medical Center, radioactive waste has been disposed of by using several disposal boxes designed for nuclear waste. However, some quantity of radioactivity has been detected occasionally due to some radiologists' carelessness not only from radioactive waste, but also from medical waste such as uncontrolled radioactive waste related to patients, poly gloves or saline solution bottles from radiopharmaceuticals laboratory. Thus, this study is going to suggest a solution to maintain the medical wastes made from controlled areas that can be below maximum permissible surface dose limits by finding the cause of radioactive contamination. Materials and methods: This study was taken place in 17 different places-2 medical wastebaskets in the waiting room, 2 medical wastebaskets in the PET room, 5 medical wastebaskets in the in vitro laboratory and 6 medical wastebaskets in the radiopharmaceuticals laboratory of the East building, 2 medical wastebaskets in the waiting room of the New building of Nuclear Medicine Department in Asan Medical Center from April to August 2010. Mean radioactivity and its standard deviation of each place have been found by measuring surface contamination of medical wastebaskets and backgrounds twice a week, totaling 30 times. An independent t-test of SPSS (Ver. 12.0) statistic program has been used for statistical analysis. Swabs, saline solution bottles and poly gloves collected from each place also measured 30 times, respectively. Results: This study analyzed medical waste and the backgrounds of each place by using survey meter detectors that significant differences of five places did not exist, but existed statistically in twelve places (p<0.05). Also, swabs, saline solution bottles and poly gloves collected from each radioactive waste partly exceed the legal dose limit as a result of measuring by a gamma counter. Conclusion: Backgrounds and the surface doses of radioactive disposal box in all 17 places measured by the survey meter did not exceed the legal dose limit; however, it obviously showed that there were prominent differences in 12 places. Assuming that the cause of the differences was swabs, saline solution bottles and gloves, we examined them by gamma counter, and the results showed remarkably high doses of radioactivity. Consequently, swabs and poly gloves which are normally disposed in the general medical waste box should be disposed in the radioactive waste box furnished by radiopharmaceuticals laboratory. Also, saline solution discharged from radioactive pharmaceutical places is considered as radioactive liquid waste so that it should be disposed of by the septic tank specifically designed for radioactive liquid.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.90-93
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• 2011

Purpose: A Pixelated BSGI gamma camera has features to enhance resolution and sensitivity and minimize the distance between detector and organs by narrow FOV. Therefore, it is known as useful device to examine small organs such as thyroid, parathyroid and gall bladder. In general, when we would like to enlarge the size of images and obtain high resolution images by gamma camera in nuclear medicine study, we use pinhole collimator. The purpose of this study is to evaluate the usefulness of Pixelated BSGI gamma camera and to compare to it using pinhole collimator in thyroid scan which is a study of typical small organs. Materials and methods: (1) The evaluation of sensitivity and spatial resolution: We measured sensitivity and spatial resolution of Pixelated BSGI with LEHR collimator and Infinia gamma camera with pinhole collimator. The sensitivity was measured by point source sensitivity test recommended by IAEA. We acquired images considering dead time in BSGI gamma camera for 100 seconds and used $^{99m}TcO4-\;400{\mu}Ci$ line source. (2) The evaluation of thyroid phantom: The thyroid phantom was filled with $^{99m}TcO4-$. After set 300 sec or 100 kcts stop conditions, we acquired images from both pixelated BSGI gamma camera and Infinia gamma camera with LEHR collimator. And we performed all thyroid studies in the same way as current AMC's procedure. Results: (1) the result of sensitivity: As a result, the sensitivity and spatial resolution of pixelated BSGI gamma camera were better than Infinia's. The sensitivities of pixelated BSGI and Infinia gamma camera were $290cps/{\mu}Ci$ and $350cps/{\mu}Ci$ respectively. So, the sensitivity of pixelated BSGI was 1.2 times higher than Infinia's (2) the result of thyroid phantom: Consequently, we confirmed that images of Pixelated BSGI gamma camera were more distinguishable between hot and cold spot compared with Infinia gamma camera. Conclusion: A pixelated BSGI gamma camera is able to shorten the acquisition time. Furthermore, the patients are exposed to radiation less than before by reducing amount of radiopharmaceutical doses. Shortening scan time makes images better by minimizing patient's breath and motion. And also, the distance between organ and detector is minimized because detector of pixelated BSGI gamma camera is small and possible to rotate. When patient cannot move at all, it is useful since device is feasible to move itself. However, although a pixelated BSGI gamma camera has these advantages, the effect of dead time occurs over 2000 cts/s since it was produced only for breast scan. So, there were low concentrations in organ. Therefore, we should consider that it needs to take tests to adjust acquisition time and amount of radiopharmaceutical doses in thyroid scan case with a pixelated BSGI gamma camera.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.19-26
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• 2008

Purpose: In general, We discharged radioactive wastewater and sewages less than $8.1{\times}10^{-13}$ Ci/ml in a exclusive water-purifier tank. Our hospital operating three exclusive water-purifier tank for radioactive wastewater and sewages of 60 tons capacity respectively. In order to meet the criteria it need a enough decay more than 125 days per each exclusive tank. However, recently we fell into the serious situation that decay period was decreased remarkably, owing to the wastewater amount increased rapidly by enlarge the therapy ward. For that reason, in this article, I'd like to say the way that reducing of radioactive wastewater and sewages rationally. Materials and Methods: From January, 2006 to October, four hundred and two cases were analyzed. They were all hospitalized during 3 days and 2 nights. We calculated the average amount of water used (include toilet water used, shower water used, washstand water used, $\cdots$), each exclusive water-purifier tank's decay period, as well as try to search the increased factors about water-purifier tank inflow flux by re-analysis of the procedure of radioisotope therapy step by step. Results: We could increase each exclusive water-purifier tank's decay period from 84 days to 130 days through the improvement about following cause: (1) Improvement of conventional toilet stool for excessive water waste $\rightarrow$ Replacement of water saving style toilet stool (2) Prevention of unnecessary shower and wash (3) Stop the diuretics taking during hospitalization (4) Analysis of relationship between water intakes and residual dose of body (5) Education about outside toilet utilization before the administration (6) Changed each water-purifier tank's maximum level from85% to 90% Conclusion: The originality of our efforts are not only software but hardware performance improvements. Incidentally the side of software's are change of therapy procedures and protocols, the side of hardware's are replacement of water saving style toilet stool and change of each water-purifier tank's maximum level. Thus even if a long lapse of time, problem such as return to the former conditions may not happen. Besides, We expect that our trials become a new reasonable model in similar situation.

• Journal of Animal Environmental Science
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• v.17 no.3
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• pp.163-170
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• 2011

This study was carried out to investigate greenhouse gas (GHG), $CH_4$ and $N_2O$, emission from liquid swine manure according to aeration levels in summer. To evaluate the influence of operation methods on GHG emissions, liquid swine manure were applied with different rates of aeration (store without aeration, $1m^3/ton/h$, $2.5m^3/ton/h$, and $5m^3/ton/h$). Following are the results of this study. The liquid swine manure applied no aeration, $1m^3/ton/h$, $2.5m^3/ton/h$, and $5m^3/ton/h$ aeration rates released 315.6, 13.9, 17.9 and $9.6{\mu}g/m^2/s$ of $CH_4$ and 0.173, 0.157, 0.131, and $0.241{\mu}g/m^2/s$ of $N_2O$, respectively. Liquid swine manure applied no aeration released the most amount of GHG ($6,681.4{\mu}g/m^2/s$ $CO_2$-Eq.) and followed by $5m^3/ton/h$ ($276.4{\mu}g/m^2/s$ $CO_2$-Eq.), $2.5m^3/ton/h$ ($416.0{\mu}g/m^2/s$ $CO_2$-Eq.), and $1m^3/ton/h$ ($340.8{\mu}g/m^2/s$ $CO_2$-Eq.). Our results reveal that the aerated system may reduce GHG emissions compared to no aeration. Consequently, aeration and mixing were effective at reducing GHG emissions during liquid swine manure storage.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.10 no.1
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• pp.51-59
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• 2007

Purpose: Recently well-developed anorectal function tests have revealed that there is an obvious pelvic floor dyssynergia (PFD) pattern in pediatric patients with constipation, as well as in adult's. The use of biofeedback therapy (BT) has been widely implemented in adult PFD patients; however, this approach has only rarely been considered for pediatric PFD patients. Therefore, we assessed the effectiveness of BT in children with PFD. Methods: We studied 70 children with PFD, who were referred to the department of pediatrics at the Asan Medical Center for the management of soiling or chronic constipation from September 2002 to February 2005. Diagnosis of PFD and assessment of the efficacy of BT for PFD treatment were carried out along with several ano-rectal function tests (cine-defecography, ano-rectal manometry, balloon expulsion test and intra-anal EMG); in addition, a questionnaire was administered. The BT based intra-anal EMG was performed. A follow-up telephone interview was performed more than 6 months later. Results: Most of the symptoms and results of the ano-rectal function tests were statistically improved after BT. In comparisons between the BT and control groups (BT refusal group due to poor compliance), the symptoms were statistically improved at follow-up. Therefore, for the shortterm improvement of symptoms, BT was better than conservative therapy alone. The negative feelings associated with ano-rectal function testing and BT were directly associated with failure or success of therapy. Conclusion: Pediatric patients with constipation or soiling that presented with an obvious PFD pattern showed that BT was a useful therapeutic tool for rapid improvement of symptoms.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.168-177
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• 2017

Purpose: The purpose of this study was to analyze the clinical features and risk factors of invasive infections caused by Lactobacillus spp. and Saccharomyces spp., components of commercially available probiotics. Methods: We analyzed demographic and clinical data from children ${\leq}18$ years of age with an invasive infection caused by Lactobacillus spp. or Saccharomyces spp. at the Asan Medical Center Children's Hospital from January 1998 to June 2016. Probiotic consumption data were also analyzed. Results: During the study period, a total of 24 episodes of invasive infections were caused by Lactobacillus spp. (n=16) and Saccharomyces cerevisiae (n=8). Along with the increase of probiotic use (755,594 [days/1,000 patient-admission days] in 2001 to 2005, 1,444,066 in 2006 to 2010, and 6,904,736 in 2011 to 2016), the incidence of probiotic-associated invasive infection increased ($R^2=0.70$). The median age of the patients was 1.8 years (range, 2 months to 17 years), and most of them had underlying medical conditions. The 30-day mortality rate was 20.8% (5/24), and 11 (45.8%) of these patients resulted from a severe invasive infection. We determined the risk factors for invasive infection to be: previous intensive care unit stay (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.5 to 6.1] and the presence of a central venous catheter (OR, 2.2; 95% CI, 1.2 to 4.3). Conclusions: Although the probiotic-associated invasive infections rarely occurred in children, the incidence has increased along with probiotic pressure. Judicious use of probiotics is mandatory, especially in young children with underlying medical conditions and continuous surveillance will be needed to minimize the safety concerns.