In case of all patients who receive radiation therapy, a treatment plan is established and all steps of treatment are planned in the same geometrical condition. In case of head and neck cancer patients who undergo simulated treatment through computed tomography (CT), patients are fixed onto a table for planning, but laid on the top of the treatment table in the radiation therapy room. This study excogitated and fabricated an adjustable holder for head and neck cancer patients to fix patient's position and geometrical discrepancies when performing radiation therapy on head and neck cancer patients, and compared the error before and after adjusting the position of patients due to difference in weight to evaluate the correlation between patients' weight and range of error. Computed tomography system(High Advantage, GE, USA) is used for phantom to maintain the supine position to acquire the images of the therapy site for IMRT. IMRT 4MV X-rays was used by applying the LINAC(21EX, Varian, U.S.A). Treatment planning system (Pinnacle, ver. 9.1h, Philips, Madison, USA) was used. The setup accuracy was compared with each measurement was repeated five times for each weight (0, 15, and 30Kg) and CBCT was performed 30 times to find the mean and standard deviation of errors before and after the adjustment of each weight. SPSS ver.19.0(SPSS Inc., Chicago, IL,USA) statistics program was used to perform the Wilcoxon Rank test for significance evaluation and the Spearman analysis was used as the tool to analyze the significance evaluation of the correlation of weight. As a result of measuring the error values from CBCT before and after adjusting the position due to the weight difference, X,Y,Z axis was
Purpose: Recently the role of vitamins, folate in particular, has been emphasized in the maintenance of health. Folate deficiency is known to give rise to developmental delay, immature vascular disease, neural tube defect, acute leukemia, atherosclerotic vascular disease, delivery defects, breast cancer, and particularly gastrointestinal neoplasia. Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in folate metaboism, and influences DNA synthesis and DNA methylation. Generally, folate deficiency is associated with gastrointestinal neoplasms. The amino-acid- changing and enzyme-activity-reducing nucleotide polymorphism (766C
Background : Home ventilation can decrease hospital-acquired infection, increase physical activity, improve nutritional status, enhance quality of life, and reduce medical costs. The number of patient using home ventilators has been increasing, particularly in Europe and United States. Although the number of patients with home ventilation has been increasing in Korea, the current status of these patients is not well known. This study was undertaken to obtain basic information upon these patients in addition to evaluating any problems related to patients' home care in our country. Methods : A register of 92 patients with home ventilators in Seoul and Kyunggi Province were obtained from commercial ventilator supply companies. The patients were contacted by phone and 29 of them accepted our visit. Information concerning education about home care before discharge, equipment cost, and problems related to home care were documented. The mode and preset variables of the home ventilator were checked; tidal volume (TV), peak airway pressure, and oxygen saturation were measured. Results : There were 26 males (90%) and their mean age was 48.0 (
Background : Though surgery plays an important role in the management of patients with Mycobacterium tuberculosis infection, there is little information regarding the timing of resection. We tried to find out the ideal timing of operation. Method: A retrospective review was performed in 69 patients underwent pulmonary resection for pulmonary tuberculosis between January 1993 and December 1997. They were categorized into various groups according to the length of preoperative specific drug therapy. The rates of treatment failure, realpse and complication in each group were compared statistically by
Background: Extubation is recommended to be performed at minimum pressure support (PSmin) during the pressure support ventilation (PSV). In field, physicians sometimes perform additional 1 hr T-piece trial to the patient at PSmin to reduce re-intubation risk. Although it provides confirmation of patient's breathing reserve, weaning could be delayed due to increased airway resistance by endotracheal tube. Methods: To investigate the effect of additional 1 hr T-piece trial on weaning outcome, a prospective study was done in consecutive 44 patients who had received mechanical ventilation more than 3 days. Respiratory mechanics, hemodymic, and gas exchange measurements were done and the level of PSmin was calculated using the equation (PSmin=peak inspiratory flow rate
Background : Recent outbreaks of pulmonary disease due to drug-resistant strains of Mycobacterium Tuberculosis have resulted in significant morbidity and mortality in patients worldwide. We reviewed our experience to evaluate the effects of pulmonary resection on the management of multidrug-resistant tuberculosis. Method : A retrospective review was performed of 41 patients undergoing pulmonary resection for multidrug-resistant tuberculosis between January 1993 and December 1997. We divided these into 3 groups according to the radiologic findings : (1) patients who have reasonably localized lesion (Localized Lesion Group ; LLG) (2) patients who have cavitary lesions after pulmonary resection on chest roentgenogram (Remained Cavity Group : RCG) (3) patients who have Remained infiltrative lesions postoperatively (Remained infiltrative group : RIG). We evaluated the negative conversion rate after resection and overall response rate of the groups. Then they were compared with the results of the chemotherapy on the multi drug-resistant tuberculosis which has been outcome by Goble et al. Goble et al reported that negative conversion rate was 65% and overall response rate, 56% over a mean period of 5.1 months. Results : Seventy five point six percent were men and 24.4% women with a median age of 31 years (range, 16 to 60 years). Although the patients were treated preoperatively with multidrug regimens in an effort to reduce the mycobacterial burden, 22 of 41 were still sputum culture positive at the time of surgery. 20 of 22 patients(90.9%, p<0.01) responded which is defined as negative sputum cultures within 2 months postoperative. Of 26 patients with the sufficient follow up data, 19 have Remained sputum culture negative for a mean duration of 25.7 months (73.1%, p<0.05). The bulk of the disease was manifest in one lung, but lesser amounts of contralateral disease were demonstrated in 15, consisted of 8 in RIG and 7 in RCG, of 41. 12 of 12 patients (100%, p<0.01) who were sputum positive at the time of surgery in LLG converted successfully. 14 of 15 patients (93.3%, p<0.05) with the follow up have completed treatment and not relapsed for a mean period of 25. 7 months. The mean length of postoperative drug therapy of LLG was 12.2 months. In RIG, postoperative negative conversion rate was 83.3% which was not significant statistically. There was a statistical significance in overall response rate (100%, p<0.05) of RIG for a mean period of 24.4 months with a mean length of postoperative chemotherapy, 11.8 months. In RCG a statistically lower overall response rate (14.3%, p<0.01) has been revealed for a mean duration of follow up, 24.2 months. A negative conversion rate of RCG was 75% which was not significant statistically. Conclusion : Surgery plays an important role in the management of patients with multidrug-resistant Mycobacterium tuberculosis infection. Aggressive pulmonary resection should be performed for resistant Mycobacterium tuberculosis infection to avoid treatment failure or relapse. Especially all cavitary lesions on preoperative chest roentgenogram should be resected completely. If all of them could not be resected perfectly, you should not open the thorax.
Recommender system has become one of the most important technologies in e-commerce in these days. The ultimate reason to shop online, for many consumers, is to reduce the efforts for information search and purchase. Recommender system is a key technology to serve these needs. Many of the past studies about recommender systems have been devoted to developing and improving recommendation algorithms and collaborative filtering (CF) is known to be the most successful one. Despite its success, however, CF has several shortcomings such as cold-start, sparsity, gray sheep problems. In order to be able to generate recommendations, ordinary CF algorithms require evaluations or preference information directly from users. For new users who do not have any evaluations or preference information, therefore, CF cannot come up with recommendations (Cold-star problem). As the numbers of products and customers increase, the scale of the data increases exponentially and most of the data cells are empty. This sparse dataset makes computation for recommendation extremely hard (Sparsity problem). Since CF is based on the assumption that there are groups of users sharing common preferences or tastes, CF becomes inaccurate if there are many users with rare and unique tastes (Gray sheep problem). This study proposes a new algorithm that utilizes Social Network Analysis (SNA) techniques to resolve the gray sheep problem. We utilize 'degree centrality' in SNA to identify users with unique preferences (gray sheep). Degree centrality in SNA refers to the number of direct links to and from a node. In a network of users who are connected through common preferences or tastes, those with unique tastes have fewer links to other users (nodes) and they are isolated from other users. Therefore, gray sheep can be identified by calculating degree centrality of each node. We divide the dataset into two, gray sheep and others, based on the degree centrality of the users. Then, different similarity measures and recommendation methods are applied to these two datasets. More detail algorithm is as follows: Step 1: Convert the initial data which is a two-mode network (user to item) into an one-mode network (user to user). Step 2: Calculate degree centrality of each node and separate those nodes having degree centrality values lower than the pre-set threshold. The threshold value is determined by simulations such that the accuracy of CF for the remaining dataset is maximized. Step 3: Ordinary CF algorithm is applied to the remaining dataset. Step 4: Since the separated dataset consist of users with unique tastes, an ordinary CF algorithm cannot generate recommendations for them. A 'popular item' method is used to generate recommendations for these users. The F measures of the two datasets are weighted by the numbers of nodes and summed to be used as the final performance metric. In order to test performance improvement by this new algorithm, an empirical study was conducted using a publically available dataset - the MovieLens data by GroupLens research team. We used 100,000 evaluations by 943 users on 1,682 movies. The proposed algorithm was compared with an ordinary CF algorithm utilizing 'Best-N-neighbors' and 'Cosine' similarity method. The empirical results show that F measure was improved about 11% on average when the proposed algorithm was used