• Title/Summary/Keyword: Image plan

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Evaluate the Change of Body Shape and the Patient Alignment State During Image-Guided Volumetric Modulated Arc Therapy in Head and Neck Cancer Patients (두경부 환자의 VMAT 시 체형변화와 환자 정렬과의 상관관계 고찰)

  • Seo, Se Jeong;Kim, Tae Woo;Choi, Min Ho;Son, Jong Gi
    • The Journal of Korean Society for Radiation Therapy
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    • v.29 no.2
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    • pp.109-117
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    • 2017
  • Objectives: The purpose of this study was to evaluate the change of body shape and the patient alignment state during image-guided volumetric modulated arc therapy in head and neck cancer patients, Materials and Methods: We performed a image-guided volumetric modulated arc therapy plan for 89 patients with head and neck cancer who underwent curative radiotherapy. Ten of them were evaluated for set up error. The landmarks of the ramus, chin, posterior neck, and clavicle were specified using ARIA software (Offline review), and the positional difference was analyzed. Results: The re-CT simulation therapy was performed in 60 men with $17{\pm}4$ cycles of treatment. The weight loss rate was $-6.47{\pm}3.5%$. 29 women performed re-CT simulation at $17{\pm}5$ cycles As a result, weight loss rate was $-5.73{\pm}2.7%$. The distance from skin to C1, C3, and C5 was measured, and both clavicle levels were observed to measure the skin shrinkage changes. The skin shrinkage standard deviations were C1 (${\pm}0.44cm$), C3 (${\pm}0.83cm$), and C5 (${\pm}1.35cm$), which is about 1 mm shrinkage per 0.5 kg reduction. Skin shrinkage according to the number of treatments was 1 ~ 4 fractions (no change), 5 ~ 13 fractions (-2 mm), 14 ~ 22 fractions (-4 mm) and 23 ~ 30 fractions (-6 mm). Conclusion: When the body shape changes about 5 mm, the central dose starts to differ about 3 % or more. Therefore, the CT simulation treatment for the adaptive therapy should be additionally performed. In addition, it is necessary to actively study the CT simulation therapy method and set up method of the lower neck and to examine the use of a new immobilization device.

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Extra Dose Measurement of Differential Slice Thickness of MVCT Image with Helical Tomotherapy (토모테라피 치료 시 MVCT Image의 Slice Thickness 차이에 따른 선량 비교)

  • Lee, Byungkoo;Kang, Suman
    • Journal of the Korean Society of Radiology
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    • v.7 no.2
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    • pp.145-149
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    • 2013
  • Helical Tomotherapy is an innovative means of delivering intensity modulated radiation therapy (IMRT) using a device that merges features of a linear accelerator and helical computed tomography (CT) scanner. Hereat, during helical tomotherapy process, megavoltage computed tomography (MVCT) image are usually used for guiding the precise set-up of patient before/after treatment delivery. But which would certainly increase the total dose for patients, this study was to investigate the imaging dose of MVCT using the cylindrical "Cheese" phantom on a tomotherapy machine. A set of cylindrical "Cheese" phantom was adopted for scanning with respectively pitch value (1, 2, 3 mm) with same number slice (10 slice), same length (approximately 9 cm) and phantom set-ups on the couch of tomotherapy system. The average MVCT imaging dose were measured using A1SL ion chamber inserted in the phantom with preset geometry. The MVCT scanning average dose for the cylindrical "Cheese" phantom was 2.24 cGy, 1.02 cGy, 0.81 cGy during respectively pitch value (pitch 1, 2, 3 mm) with same number slice (10 slice), and same length's average dose was 2.47 cGy, 1.28 cGy, 0.88 cGy respectively (pitch 1, 2, 3 mm). Two major parameters, the assigned pitch numbers and scanning length, where the most important impacts to the dose variation. The MVCT dose was inversely proportional to the CT pitch value. The results may provide a reliable guidance for proper planning design of the scanning region, which is valuable to help minimize the extra dose to patient. Questionnaires were distributed to Radiology departments at hospitals with 300 sickbeds throughout the Pohang region of North Gyeongsang Province concerning awareness and performance levels of infection control. The investigation included measurements of the pollution levels of imaging equipment and assistive apparatuses in order to prepare a plan for the activation of prevention and management of hospital infections. The survey was designed to question respondents in regards to personal data, infection management prevention education, and infection management guidelines.

Development of the Multi-Parametric Mapping Software Based on Functional Maps to Determine the Clinical Target Volumes (임상표적체적 결정을 위한 기능 영상 기반 생물학적 인자 맵핑 소프트웨어 개발)

  • Park, Ji-Yeon;Jung, Won-Gyun;Lee, Jeong-Woo;Lee, Kyoung-Nam;Ahn, Kook-Jin;Hong, Se-Mie;Juh, Ra-Hyeong;Choe, Bo-Young;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.21 no.2
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    • pp.153-164
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    • 2010
  • To determine the clinical target volumes considering vascularity and cellularity of tumors, the software was developed for mapping of the analyzed biological clinical target volumes on anatomical images using regional cerebral blood volume (rCBV) maps and apparent diffusion coefficient (ADC) maps. The program provides the functions for integrated registrations using mutual information, affine transform and non-rigid registration. The registration accuracy is evaluated by the calculation of the overlapped ratio of segmented bone regions and average distance difference of contours between reference and registered images. The performance of the developed software was tested using multimodal images of a patient who has the residual tumor of high grade gliomas. Registration accuracy of about 74% and average 2.3 mm distance difference were calculated by the evaluation method of bone segmentation and contour extraction. The registration accuracy can be improved as higher as 4% by the manual adjustment functions. Advanced MR images are analyzed using color maps for rCBV maps and quantitative calculation based on region of interest (ROI) for ADC maps. Then, multi-parameters on the same voxels are plotted on plane and constitute the multi-functional parametric maps of which x and y axis representing rCBV and ADC values. According to the distributions of functional parameters, tumor regions showing the higher vascularity and cellularity are categorized according to the criteria corresponding malignant gliomas. Determined volumes reflecting pathological and physiological characteristics of tumors are marked on anatomical images. By applying the multi-functional images, errors arising from using one type of image would be reduced and local regions representing higher probability as tumor cells would be determined for radiation treatment plan. Biological tumor characteristics can be expressed using image registration and multi-functional parametric maps in the developed software. The software can be considered to delineate clinical target volumes using advanced MR images with anatomical images.

Research on the Visual Historical & Cultural Resources of Seongbuk-dong (서울 성북동 역사문화자원 주변경관의 시각적 특성연구)

  • Lee, Won-Ho;Kim, Jae-Ung
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.31 no.2
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    • pp.118-127
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    • 2013
  • In this study, Seongbuk-dong historical & cultural resources of the surrounding landscape were analyzed by the visual characteristics of the landscape adjective analysis. Research was investigate to the relationship between visual characteristics and preferences and Research in the following way. Selected historical and cultural resources in the surrounding area are located in Seongbuk-dong 30 slices the survey was conducted. Landscape preference factors to identify the scale of 16 adjectives and then factor analysis was conducted. Lastly, Analysis of variance and regression analysis were conducted in order to determine the impact of the last image factors on visual preferences. Firstly, The results can be summarized as follows. Officer for 30 pictures appear in Seongbuk-dong in the historical and cultural resources, and distributed around the target preference for the 16 adjectives analysis yielded an average result of overall preference were analyzed and that is a 3.72 average. In these photos, VP8, VP9, VP10, VP12, VP15; 4.5 points more than one order higher. The reason is limit of altitude by the Seoul landscape plan for the historical and cultural resources around. It also judged important reason that history and Culture are in harmony with the surrounding cultural property in the conservation area. Secondly, Important factors are factor 1(aesthetic factors), factor 2(cultural factors), factor 3(physical factors) and three factors could be identified. Results of the analysis of variance and regression analysis about factors for visual preference and image shows value of psychological factor is most significant to explain for nearby history &cultural resources of Seongbuk-dong of scenery around. As a result, the state can not view historical and cultural resources for analysis will be located in a residential area near the historical and cultural resources for aesthetic factors. Third, the negative side of the argument is a residential area which is not arranged surrounding landscape maintenance of historical and cultural resources has emerged. Historical and cultural resources in harmony with the phenomena of the physical, cultural, and aesthetic characteristics of the three areas is a positive factor in the high incidence. Factors from that are expressed in this study by analyzing multi-dimensional analysis to derive a factor to be considered important in the management of historical and cultural resources, landscape around is required.

A Study on the Composition Principle of the Gyeongbokgung Drainage Facility - Focused on the review of Gyeongbokgung excavation survey - (경복궁(景福宮) 배수시설(排水施設)의 조성원리(造成原理)에 관한 연구 - 경복궁 발굴조사 자료에 대한 검토를 중심으로 -)

  • Kim, Tae Min;Nam, Ho Hyun
    • Korean Journal of Heritage: History & Science
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    • v.51 no.4
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    • pp.120-145
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    • 2018
  • This study intended to examine the drainage facility of Gyeongbokgung Palace based on the traces of the relic found during the excavation survey. Historical records indicate that various efforts have been made for smooth drainage facility for the palace since the foundation of the Joseon Dynasty. Although there are no drawings showing the image of early appearance of Gyeongbokgung Palace during the foundation, it is possible to estimate it through the drawings prepared after the King Yeongjo's reign. The image of the palace after reconstruction can be seen through the "Bukgwoldohyeong" and other relevant documents. At this present, since the survey intends to determine the image of Gyeongbokgung Palace during the reign of King Gojong based on the standard restoration plan of the Cultural Heritage Administration, this study also focused on the drainage facility of Gyeongbokgung Palace during King Gojong's reign, particularly on the collecting wells and culverts of six areas including "Chimjeon Hall", "Taewonjeon Hall", "Geoncheongung Hall", "Sojubang Hall", "Hamhwadang - Jipgyeongdang - Yeonghundang Hall", and "Heungbokjeon Hall". Gyeongbokgung Palace is divided into various zones composed of the central halls and surrounding corridors, and the drains also primarily start from each hall and later join the central drain of the zone. The central drain then leads to the "Eo-gu(御溝)" and the water led to the "Eo-gu" is finally discharged through the water gate. It appears that this series of processes were basically devised to coordinate artificial drain with the natural drain using the natural geographical features of the palace. Research showed that the collecting well where the draining begin was installed in the area where a large amount of household sewage was generated but mostly in the corners where corridors met or corridors and wall met. This appears to be an arrangement to handle the water falling from the roof and household sewage. Also, "Ju(廚)" was installed mainly at the end of the corridor to handle household sewage. The installation of these drainage facilities shows the possibility that the drainage of Gyeongbokgung was very compact under a series of plans.

A Comparison of Body Image and Dietary Behavior in Middle and High School girls in Gyeongbuk Area (경북 일부지역 여자 중·고등학생의 체형인식도 및 식생활 행동 비교)

  • Kim, Hye-Jin;Lee, Kyung-A
    • Korean journal of food and cookery science
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    • v.31 no.4
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    • pp.497-504
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    • 2015
  • The purpose of this study was to compare body image and dietary behavior in middle and high school girls in the Gyeongbuk area in September, 2014. Data were collected from a total of 194 middle school and 170 high school girls through a self-reported questionnaire. A total of 364 completed questionnaires were collected and used for the final analysis. The mean body mass index (BMI) of respondents was normal at 21.29. Generally, high school girls had greater height, weight and BMI than middle school girls. Height (p<0.001) and weight (p<0.001) were significantly different, while BMI was not. The ratio of students who perceived their body size as 'Fat' was significantly (p<0.05) higher in high school (43.9%) than in middle school (31.6%). The ratio of dissatisfaction with their current body image was significantly (p<0.001) higher in high school girls (64.1%) than in middle school girls (44.0%). Among respondents who perceived their body size as 'Fat', many high school girls actually (53.3%) had normal or low body weight and this was significantly (p<0.001) higher than in middle school girls (39.3%). Experience with weight control was higher in high school girls (67.3%) than in middle school girls (60.6%), but there was no significant difference. Regarding the weight control methods, respondents selected 'combination diet and exercise' (22.2%), 'diet control' (20.9%), 'exercise' (18.7%), and 'reduce snacks and midnight snack' (17.4%). 15 items under obesity-related dietary behavior were measured with 5-point scales and lower scores indicated obesity diet behavior. The mean score for all respondents was 3.19/5.00, and high school girls (3.06) scored significantly (p<0.001) higher than middle school girls (3.33). Our study suggests that the development of effective nutrition and health education for diet control is crucial for adolescent girls. This study will enable educators to plan more effective strategies to improve the dietary knowledge of adolescent girls.

Packing effects on the intracavitary radiation Therapy 3-Dimension plan of the uterine cervix cancer (자궁경부암 강내조사 3차원 치료계획 시 Packing의 유용성 분석)

  • Si, Chang-Keun;Jo, Jung-Kun;Lee, Du-Hyun;Kim, Sun-Yeung;Kim, Tae-Yoon
    • The Journal of Korean Society for Radiation Therapy
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    • v.17 no.1
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    • pp.1-8
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    • 2005
  • Purpose : An effect of a packing to uterine treatment of a cervical cancer using a dose-volume histogram for a point dose and a volume dose of the bladder and the rectum was analyzed by establishing a three-dimensional treatment plan using a CT image. Materials and methods : Reference points of the bladder and the rectum were marked, respectively at a treatment plan device (plato brachytherapy V14.2.4) by photographing CT(marconi, USA) when the packing was used and removed under the same condition and a treatment plan was performed to Apoint depending on ICRU38. However, in case of the rectum, a maximum point was looked up and compared with the above point because the point presented from the ICRU is not proper as a representative value of a rectum point dose. Further, the volume dose depending on volume of $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder was measured. The measured values were used to analyze the effect of the packing through a Wilcoxon Signed Rank Test (a SAS statistical analysis process program). Result : The reference points at the bladder and rectum doses when the packing was removed were $116.94\;35.42\%$ and $117.59\;21.08\%$, respectively. The points when the packing was used were $107.08\;38.12\%$ and $95.19\;21.32\%$, respectively. After the packing was used, the reference points at the bladder and the rectum were decreased by $9.86\%$ and $22.4\%$, respectively. When the packing was removed, the maximum points at the bladder and the rectum were $164.51\;50.89\%,\;128.81\;33.05\%$, respectively. When the packing was used, the maximum points at the bladder and the rectum were $142.31\;44.79,\;110.08\;37.03\%$, respectively. After the packing was used, the maximum points at the bladder and the rectum were decreased by $22.2\%$ and $18.73\%$, respectively. When the packing was removed, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were $48.62{\pm}18.09\%,\;16.12{\pm}11.15\%,\;and\;7.51{\pm}6.63\%$, respectively and its rectum volume were $23.41{\pm}14.44\%,\;6.27{\pm}4.28\%,\;2.79{\pm}2.27\%$, respectively. When the packing was used, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were $40.33{\pm}16.72,\;11.63{\pm}8.72,\;and\;4.87{\pm}4.75\%$, respectively and its rectum volume were $18.96{\pm}8.37\%,\;4.75{\pm}2.58\%,\;and\;1.58{\pm}1.06\%$, respectively. After the packing was used, the bladder volume at $50\%,\;80\%,\;and\;100\%$ point doses of the rectum and the bladder were decreased by $8.29\%,\;4.49\%,\;and\;2.64\%$, respectively and its bladder volume were decreased by $4.45\%,\;1.52\%,\;and\;1.21\%$, respectively. Conclusion : Values at Reference point doses of the bladder and the rectum recommended from the ICRU 38 were 0.0781 and 0.0781, respectively and values of their maximum point doses were 0.0156 and 0.0156, respectively, as a result of which an effect of the packing using at the uterine intracavitary treatment of an uterine cervical cancer through the three-dimensional treatment plan used CT were measured. That is, the values at reference point doses and the values at maximum point doses show similar difference. However, P value was 0.15 at over $50\%,\;80\%,\;and\;100\%$ volume doses and the value shows no similar difference. In other words, the effect of the packing looks like having a difference at the point dose, but actually shows no difference at the volume dose. The reason is that the volume of the bladder and the rectum are wide but the volume of the packing is only a portion. Therefore, the effect of decreasing the point dose was not great. Further, the farer the distance is, the more weak the intensity of radiation is because the intensity of radiation is proportional to inverse square of a distance. Therefore, the effort to minimize an obstacle of the bladder and the rectum by using the packing should be made.

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Evaluation of the Usefulness of Restricted Respiratory Period at the Time of Radiotherapy for Non-Small Cell Lung Cancer Patient (비소세포성 폐암 환자의 방사선 치료 시 제한 호흡 주기의 유용성 평가)

  • Park, So-Yeon;Ahn, Jong-Ho;Suh, Jung-Min;Kim, Yung-Il;Kim, Jin-Man;Choi, Byung-Ki;Pyo, Hong-Ryul;Song, Ki-Won
    • The Journal of Korean Society for Radiation Therapy
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    • v.24 no.2
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    • pp.123-135
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    • 2012
  • Purpose: It is essential to minimize the movement of tumor due to respiratory movement at the time of respiration controlled radiotherapy of non-small cell lung cancer patient. Accordingly, this Study aims to evaluate the usefulness of restricted respiratory period by comparing and analyzing the treatment plans that apply free and restricted respiration period respectively. Materials and Methods: After having conducted training on 9 non-small cell lung cancer patients (tumor n=10) from April to December 2011 by using 'signal monitored-breathing (guided- breathing)' method for the 'free respiratory period' measured on the basis of the regular respiratory period of the patents and 'restricted respiratory period' that was intentionally reduced, total of 10 CT images for each of the respiration phases were acquired by carrying out 4D CT for treatment planning purpose by using RPM and 4-dimensional computed tomography simulator. Visual gross tumor volume (GTV) and internal target volume (ITV) that each of the observer 1 and observer 2 has set were measured and compared on the CT image of each respiratory interval. Moreover, the amplitude of movement of tumor was measured by measuring the center of mass (COM) at the phase of 0% which is the end-inspiration (EI) and at the phase of 50% which is the end-exhalation (EE). In addition, both observers established treatment plan that applied the 2 respiratory periods, and mean dose to normal lung (MDTNL) was compared and analyzed through dose-volume histogram (DVH). Moreover, normal tissue complication probability (NTCP) of the normal lung volume was compared by using dose-volume histogram analysis program (DVH analyzer v.1) and statistical analysis was performed in order to carry out quantitative evaluation of the measured data. Results: As the result of the analysis of the treatment plan that applied the 'restricted respiratory period' of the observer 1 and observer 2, there was reduction rate of 38.75% in the 3-dimensional direction movement of the tumor in comparison to the 'free respiratory period' in the case of the observer 1, while there reduction rate was 41.10% in the case of the observer 2. The results of measurement and comparison of the volumes, GTV and ITV, there was reduction rate of $14.96{\pm}9.44%$ for observer 1 and $19.86{\pm}10.62%$ for observer 2 in the case of GTV, while there was reduction rate of $8.91{\pm}5.91%$ for observer 1 and $15.52{\pm}9.01%$ for observer 2 in the case of ITV. The results of analysis and comparison of MDTNL and NTCP illustrated the reduction rate of MDTNL $3.98{\pm}5.62%$ for observer 1 and $7.62{\pm}10.29%$ for observer 2 in the case of MDTNL, while there was reduction rate of $21.70{\pm}28.27%$ for observer 1 and $37.83{\pm}49.93%$ for observer 2 in the case of NTCP. In addition, the results of analysis of correlation between the resultant values of the 2 observers, while there was significant difference between the observers for the 'free respiratory period', there was no significantly different reduction rates between the observers for 'restricted respiratory period. Conclusion: It was possible to verify the usefulness and appropriateness of 'restricted respiratory period' at the time of respiration controlled radiotherapy on non-small cell lung cancer patient as the treatment plan that applied 'restricted respiratory period' illustrated relative reduction in the evaluation factors in comparison to the 'free respiratory period.

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A study on The U.S.-Korean Trade Friction Prevention and Settlement in the Fields of Information and Telecommunication Industries (한미간(韓美間) 정보통신분야(情報通信分野) 통상마찰예방(通商摩擦豫防)과 해소방안(解消方案)에 관한 연구(硏究))

  • Jung, Jay-Young
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.13
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    • pp.869-895
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    • 2000
  • The US supports the Information and Communication (IC) industry as a strategic one to wield a complete power over the World Market. However, several other countries are also eager to have the support for the IC industry because the industry produces a high added value and has a significant effect on other industries. Korea is not an exception. Korea recently succeeded in the commercialization of CDMA for the first time in the world, after the successful development of TDX. Hence, it is highly likely to get tracked by the US. Although the IC industry is a specific sector of IT, there is a concern that there might be a trade friction between the US and Korea due to a possible competition. It will be very important to prepare a solution in advance so that Korea could prevent the friction and at the same time increase its share domestically and globally. It will be our important task to solve the problem with the minimum cost if the conflict arises unfortunately in the IT area. The parties that have a strong influence on the US trade policy are the think tank group and the IT-related interest group. Therefore, it would be important to have a close relationship with them. We found some implications by analyzing the case of Japan, which has experienced trade frictions with the US over the long period of time in the high tech industry. In order to get rid of those conflicts with the US, the Japanese did the following things : (1) The Japanese government developed supporting theories and also resorted to international support so that the world could support the Japanese theories. (2) Through continual dialogue with the US business people, the Japanese business people sought after solutions to share profits among the Japanese and the US both in the domestic and in the worldwide markets. They focused on lobbying activities to influence the US public opinion to support the Japanese. The specific implementation plan was first to open culture lobby toward opinion leaders who were leaders about the US opinion. The institution, Japan Society, were formed to deliver a high quality lobbying activities. The second plan is economic lobby. They have established Japanese Economic Institute at Washington. They provide information about Japan regularly or irregularly to the US government, research institution, universities, etc., that are interested in Japan. The main objective behind these activities though is to advertise the validity of Japanese policy. Japanese top executives, practical interest groups on international trade, are trying to justify their position by direct contact with the US policy makers. The third one is political lobby. Japan is very careful about this political lobby. It is doing its best not to give impression that Japan is trying to shape the US policy making. It is collecting a vast amount of information to make a correct judgment on situation. It is not tilted toward one political party or the other, and is rather developing a long-term network of people who understand and support the Japanese policy. The following implications were drawn from the experience of Japan. First, the Korean government should develop a long-term plan and execute it to improve the Korean image perceived by American people. Second, the Korean government should begin public relation activities toward the US elite group. It is inevitable to make an effort to advertise Korea to this elite group because this group leads public opinion in the USA. Third, the Korean government needs the development of a relevant policy to elevate the positive atmosphere for advertising toward the US. For example, we need information about to whom and how to about lobbying activities, personnel network who immediately respond to wrong articles about Korea in the US press, and lastly the most recent data bank of Korean support group inside the USA. Fourth, the Korean government should create an atmosphere to facilitate the advertising toward the US. Examples include provision of incentives in tax on the expenses for the advertising toward the US and provision of rewards to those who significantly contribute to the advertising activities. Fifth, the Korean government should perform the role of a bridge between Korean and the US business people. Sixth, the government should promptly analyze the policy of IT industry, a strategic area, and timely distribute information to industries in Korea. Since the Korean government is the only institution that has formal contact with the US government, it is highly likely to provide information of a high quality. The followings are some implications for business institutions. First, Korean business organization should carefully analyze and observe the business policy and managerial conditions of US companies. It is very important to do so because all the trade frictions arise at the business level. Second, it is also very important that the top management of Korean firms contact the opinion leaders of the US. Third, it is critically needed that Korean business people sent to the USA do their part for PR activities. Fourth, it is very important to advertise to American employees in Korean companies. If we cannot convince our American employees, it would be a lot harder to convince regular American. Therefore, it is very important to make the American employees the support group for Korean ways. Fifth, it should try to get much information as early as possible about the US firms policy in the IT area. It should give an enormous effort on early collection of information because by doing so it has more time to respond. Sixth, it should research on the PR cases of foreign enterprise or non-American companies inside the USA. The research needs to identify the success factors and the failure factors. Finally, the business firm will get more valuable information if it analyzes and responds to, according to each medium.

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Evaluation of Planning Dose Accuracy in Case of Radiation Treatment on Inhomogeneous Organ Structure (불균질부 방사선치료 시 계획 선량의 정확성 평가)

  • Kim, Chan Yong;Lee, Jae Hee;Kwak, Yong Kook;Ha, Min Yong
    • The Journal of Korean Society for Radiation Therapy
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    • v.25 no.2
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    • pp.137-143
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    • 2013
  • Purpose: We are to find out the difference of calculated dose of treatment planning system (TPS) and measured dose in case of inhomogeneous organ structure. Materials and Methods: Inhomogeneous phantom is made with solid water phantom and cork plate. CT image of inhomogeneous phantom is acquired. Treatment plan is made with TPS (Pinnacle3 9.2. Royal Philips Electronics, Netherlands) and calculated dose of point of interest is acquired. Treatment plan was delivered in the inhomogeneous phantom by ARTISTE (Siemens AG, Germany) measured dose of each point of interest is obtained with Gafchromic EBT2 film (International Specialty Products, US) in the gap between solid water phantom or cork plate. To simulate lung cancer radiation treatment, artificial tumor target of paraffin is inserted in the cork volume of inhomogeneous phantom. Calculated dose and measured dose are acquired as above. Results: In case of inhomogeneous phantom experiment, dose difference of calculated dose and measured dose is about -8.5% at solid water phantom-cork gap and about -7% lower in measured dose at cork-solid water phantom gap. In case of inhomogeneous phantom inserted paraffin target experiment, dose difference is about 5% lower in measured dose at cork-paraffin gap. There is no significant difference at same material gap in both experiments. Conclusion: Radiation dose at the gap between two organs with different electron density is significantly lower than calculated dose with TPS. Therefore, we must be aware of dose calculation error in TPS and great care is suggested in case of radiation treatment planning on inhomogeneous organ structure.

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