• Title/Summary/Keyword: condition evaluation method

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The Evaluation of Attenuation Difference and SUV According to Arm Position in Whole Body PET/CT (전신 PET/CT 검사에서 팔의 위치에 따른 감약 정도와 SUV 변화 평가)

  • Kwak, In-Suk;Lee, Hyuk;Choi, Sung-Wook;Suk, Jae-Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.2
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    • pp.21-25
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    • 2010
  • Purpose: For better PET imaging with accuracy the transmission scanning is inevitably required for attenuation correction. The attenuation is affected by condition of acquisition and patient position, consequently quantitative accuracy may be decreased in emission scan imaging. In this paper, the present study aims at providing the measurement for attenuation varying with the positions of the patient's arm in whole body PET/CT, further performing the comparative analysis over its SUV changes. Materials and Methods: NEMA 1994 PET phantom was filled with $^{18}F$-FDG and the concentration ratio of insert cylinder and background water fit to 4:1. Phantom images were acquired through emission scanning for 4min after conducting transmission scanning by using CT. In an attempt to acquire image at the state that the arm of the patient was positioned at the lower of ahead, image was acquired in away that two pieces of Teflon inserts were used additionally by fixing phantoms at both sides of phantom. The acquired imaged at a were reconstructed by applying the iterative reconstruction method (iteration: 2, subset: 28) as well as attenuation correction using the CT, and then VOI was drawn on each image plane so as to measure CT number and SUV and comparatively analyze axial uniformity (A.U=Standard deviation/Average SUV) of PET images. Results: It was found from the above phantom test that, when comparing two cases of whether Teflon insert was fixed or removed, the CT number of cylinder increased from -5.76 HU to 0 HU, while SUV decreased from 24.64 to 24.29 and A.U from 0.064 to 0.052. And the CT number of background water was identified to increase from -6.14 HU to -0.43 HU, whereas SUV decreased from 6.3 to 5.6 and A.U also decreased from 0.12 to 0.10. In addition, as for the patient image, CT number was verified to increase from 53.09 HU to 58.31 HU and SUV decreased from 24.96 to 21.81 when the patient's arm was positioned over the head rather than when it was lowered. Conclusion: When arms up protocol was applied, the SUV of phantom and patient image was decreased by 1.4% and 9.2% respectively. With the present study it was concluded that in case of PET/CT scanning against the whole body of a patient the position of patient's arm was not so much significant. Especially, the scanning under the condition that the arm is raised over to the head gives rise to more probability that the patient is likely to move due to long scanning time that causes the increase of uptake of $^{18}F$-FDG of brown fat at the shoulder part together with increased pain imposing to the shoulder and discomfort to a patient. As regarding consideration all of such factors, it could be rationally drawn that PET/CT scanning could be made with the arm of the subject lowered.

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A New Exploratory Research on Franchisor's Provision of Exclusive Territories (가맹본부의 배타적 영업지역보호에 대한 탐색적 연구)

  • Lim, Young-Kyun;Lee, Su-Dong;Kim, Ju-Young
    • Journal of Distribution Research
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    • v.17 no.1
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    • pp.37-63
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    • 2012
  • In franchise business, exclusive sales territory (sometimes EST in table) protection is a very important issue from an economic, social and political point of view. It affects the growth and survival of both franchisor and franchisee and often raises issues of social and political conflicts. When franchisee is not familiar with related laws and regulations, franchisor has high chance to utilize it. Exclusive sales territory protection by the manufacturer and distributors (wholesalers or retailers) means sales area restriction by which only certain distributors have right to sell products or services. The distributor, who has been granted exclusive sales territories, can protect its own territory, whereas he may be prohibited from entering in other regions. Even though exclusive sales territory is a quite critical problem in franchise business, there is not much rigorous research about the reason, results, evaluation, and future direction based on empirical data. This paper tries to address this problem not only from logical and nomological validity, but from empirical validation. While we purse an empirical analysis, we take into account the difficulties of real data collection and statistical analysis techniques. We use a set of disclosure document data collected by Korea Fair Trade Commission, instead of conventional survey method which is usually criticized for its measurement error. Existing theories about exclusive sales territory can be summarized into two groups as shown in the table below. The first one is about the effectiveness of exclusive sales territory from both franchisor and franchisee point of view. In fact, output of exclusive sales territory can be positive for franchisors but negative for franchisees. Also, it can be positive in terms of sales but negative in terms of profit. Therefore, variables and viewpoints should be set properly. The other one is about the motive or reason why exclusive sales territory is protected. The reasons can be classified into four groups - industry characteristics, franchise systems characteristics, capability to maintain exclusive sales territory, and strategic decision. Within four groups of reasons, there are more specific variables and theories as below. Based on these theories, we develop nine hypotheses which are briefly shown in the last table below with the results. In order to validate the hypothesis, data is collected from government (FTC) homepage which is open source. The sample consists of 1,896 franchisors and it contains about three year operation data, from 2006 to 2008. Within the samples, 627 have exclusive sales territory protection policy and the one with exclusive sales territory policy is not evenly distributed over 19 representative industries. Additional data are also collected from another government agency homepage, like Statistics Korea. Also, we combine data from various secondary sources to create meaningful variables as shown in the table below. All variables are dichotomized by mean or median split if they are not inherently dichotomized by its definition, since each hypothesis is composed by multiple variables and there is no solid statistical technique to incorporate all these conditions to test the hypotheses. This paper uses a simple chi-square test because hypotheses and theories are built upon quite specific conditions such as industry type, economic condition, company history and various strategic purposes. It is almost impossible to find all those samples to satisfy them and it can't be manipulated in experimental settings. However, more advanced statistical techniques are very good on clean data without exogenous variables, but not good with real complex data. The chi-square test is applied in a way that samples are grouped into four with two criteria, whether they use exclusive sales territory protection or not, and whether they satisfy conditions of each hypothesis. So the proportion of sample franchisors which satisfy conditions and protect exclusive sales territory, does significantly exceed the proportion of samples that satisfy condition and do not protect. In fact, chi-square test is equivalent with the Poisson regression which allows more flexible application. As results, only three hypotheses are accepted. When attitude toward the risk is high so loyalty fee is determined according to sales performance, EST protection makes poor results as expected. And when franchisor protects EST in order to recruit franchisee easily, EST protection makes better results. Also, when EST protection is to improve the efficiency of franchise system as a whole, it shows better performances. High efficiency is achieved as EST prohibits the free riding of franchisee who exploits other's marketing efforts, and it encourages proper investments and distributes franchisee into multiple regions evenly. Other hypotheses are not supported in the results of significance testing. Exclusive sales territory should be protected from proper motives and administered for mutual benefits. Legal restrictions driven by the government agency like FTC could be misused and cause mis-understandings. So there need more careful monitoring on real practices and more rigorous studies by both academicians and practitioners.

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Study on the Evaluation of Renal Function According to Set a Partial Region of Interest in 99mTc-DMSA scan of the Pediatric Patient with a Duplicated Ureter (중복요관을 가진 소아환자의 99mTc-DMSA 검사에서 부분적 관심영역 설정에 따른 신기능 평가에 관한 연구)

  • Nam-Koong, Hyuk;Oh, Shin Hyun;Kim, Jung Yul;Choi, Yoon Jung;Kim, Jae Sam;Lee, Chang Ho
    • The Korean Journal of Nuclear Medicine Technology
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    • v.17 no.1
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    • pp.43-47
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    • 2013
  • Purpose: A duplicated ureter is congenital renal malformations with ureter in two. Patients with duplicated ureter are in force to $^{99m}Tc-DMSA$ scan at surgery before and after. In existing examination, at produce result after $^{99m}Tc-DMSA$ scan, didn't compare to upper pole and lower pole with malformed kidney and compared to only relative uptake ratio. Therefore, this study will examine about utility of set a partial region of interest and to functional recovery of renal cell through change of upper pole uptake ratio of malformed kidney by setting each partial region of interest in upper pole and lower pole of malformed kidney in $^{99m}Tc-DMSA$ examination in surgery before and after. Materials and Methods: Pediatric patients with malformed kidney of incomplete duplicated ureter, 15 patients were enrolled in this study. Scanning were scan 3 to 4 hours after injection of $^{99m}Tc-DMSA$ 1.5 ~ 1.9 MBq/kg. Region of interest were each set in normal kidney, upper pole and lower pole with malformed kidney. Region of interest were set with same condition and method to images of surgery before and after that radio technologist 1 person, resident of nuclear medicine 1 person and doctor of urology together. Therefore, this study were compared to uptake ratio (A: B: C) that normal kidney (A), lower pole of malformed kidney (B) and upper pole of malformed kidney (C) about uptake ratio changes of malformed kidney in follow-up examination of surgery before and after. Results: When compared to 15 patients, uptake ratios were increased 7 persons and decreased 8 persons. Among increased 7 persons, it were periods of follow-up examination that 2 persons were 14 months, 4 persons were 12 months and 1 person was 8 months after surgery. Among decreased 8 persons, it were periods of follow-up examination that 4 persons were 12 months 3 persons were 6 months and 1 persons were 4 months after surgery. Conclusion: Existing study could not see the exact uptake ratio changes of malformed kidney because using only the overall Left-Right kidney uptake ratios. But a setting partial region of interest was able to see exactly what changes in the uptake of each upper pole and lower pole of malformed kidney. Because recovery of renal parenchymal cells is difficult in an evaluation of short period of time, follow-up examination should be made in long period of time. How to set up partial region of interest be thought that it would be useful.

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The Influence Evaluation of $^{201}Tl$ Myocardial Perfusion SPECT Image According to the Elapsed Time Difference after the Whole Body Bone Scan (전신 뼈 스캔 후 경과 시간 차이에 따른 $^{201}Tl$ 심근관류 SPECT 영상의 영향 평가)

  • Kim, Dong-Seok;Yoo, Hee-Jae;Ryu, Jae-Kwang;Yoo, Jae-Sook
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.67-72
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    • 2010
  • Purpose: In Asan Medical Center we perform myocardial perfusion SPECT to evaluate cardiac event risk level for non-cardiac surgery patients. In case of patients with cancer, we check tumor metastasis using whole body bone scan and whole body PET scan and then perform myocardial perfusion SPECT to reduce unnecessary exam. In case of short term in patients, we perform $^{201}Tl$ myocardial perfusion SPECT after whole body bone scan a minimum 16 hours in order to reduce hospitalization period but it is still the actual condition in which the evaluation about the affect of the crosstalk contamination due to the each other dissimilar isotope administration doesn't properly realize. So in our experiments, we try to evaluate crosstalk contamination influence on $^{201}Tl$ myocardial perfusion SPECT using anthropomorphic torso phantom and patient's data. Materials and Methods: From 2009 August to September, we analyzed 87 patients with $^{201}Tl$ myocardial perfusion SPECT. According to $^{201}Tl$ myocardial perfusion SPECT yesterday whole body bone scan possibility of carrying out, a patient was classified. The image data are obtained by using the dual energy window in $^{201}Tl$ myocardial perfusion SPECT. We analyzed $^{201}Tl$ and $^{99m}Tc$ counts ratio in each patients groups obtained image data. We utilized anthropomorphic torso phantom in our experiment and administrated $^{201}Tl$ 14.8 MBq (0.4 mCi) at myocardium and $^{99m}Tc$ 44.4 MBq (1.2 mCi) at extracardiac region. We obtained image by $^{201}Tl$ myocardial perfusion SPECT without gate method application and analyzed spatial resolution using Xeleris ver 2.0551. Results: In case of $^{201}Tl$ window and the counts rate comparison result yesterday whole body bone scan of being counted in $^{99m}Tc$ window, the difference in which a rate to 24 hours exponential-functionally notes in 1:0.114 with Ventri (GE Healthcare, Wisconsin, USA), 1:0.249 after the bone tracer injection in 12 hours in 1:0.411 with 1:0.79 with Infinia (GE healthcare, Wisconsin, USA) according to a reduction a time-out was shown (Ventri p=0.001, Infinia p=0.001). Moreover, the rate of the case in which it doesn't perform the whole body bone scan showed up as the average 1:$0.067{\pm}0.6$ of Ventri, and 1:$0.063{\pm}0.7$ of Infinia. According to the phantom after experiment spatial resolution measurement result, and an addition or no and time-out of $^{99m}Tc$ administrated, it doesn't note any change of FWHM (p=0.134). Conclusion: Through the experiments using anthropomorphic torso phantom and patients data, we found that $^{201}Tl$ myocardium perfusion SPECT image later carried out after the bone tracer injection with 16 hours this confirmed that it doesn't receive notable influence in spatial resolution by $^{99m}Tc$. But this investigation is only aimed to image quality, so it needs more investigation in patient's radiation dose and exam accuracy and precision. The exact guideline presentation about the exam interval should be made of the validation test which is exact and in which it is standardized about the affect of the crosstalk contamination according to the isotope use in which it is different later on.

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Evaluation of Physiological Changes in Watermelon Stalk during Storage under Various Conditions of Treatments after Harvesting (수확 후 저장환경에 따른 수박줄기의 생리변화)

  • Park, Shin;Kang, Sun-Chul
    • Korean Journal of Environmental Agriculture
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    • v.24 no.1
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    • pp.56-60
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    • 2005
  • In order to increase the storage stability of watermelon stalk, storage environments such as temperature and other treatments such as vaseline, mixture of soybean oil and wheat flour, and coated paper label were tested separately after harvesting. At different storage temperatures (7, 18 and $30^{\circ}C$) shelf-life of stalk was inversely proportional to temperature. The results showed that during storage at $30^{\circ}C$ they were completely wilted in 7 days, at $18^{\circ}C$ in 15 days and at $7^{\circ}C$ in 19 days. Our data also showed that stability of watermelon stalk depending on temperature was very closely correlated with water content of watermelon stalk; during storage at $30^{\circ}C$ the water content of watermelon stalk was decreased to 21.1 % in 7 days, whereas at $7^{\circ}C$ the water content was decreased gradually to 71.2 % for 19 days of storage. In order to reduce the physiological changes in watermelon stalk at $30^{\circ}C$, following treatments such as vaseline, mixture of soybean oil and wheat flour, and coated paper label were tested. As a result, watermelon stalk without any treatment was completely wilted in 9 days, while stalks treated with vaseline and mixture of soybean oil with wheat flour were wilted in 15 and 12 days, respectively. The wilt delay was noted in the watermelon stalk for $3{\sim}6$ days during both treatments but the outward quality was found detracted, whereas when treated with coated paper label, the wilt of stalk was delayed for 3 days along with the improvement in the outward quality. Therefore this data indicate that the treatment of coated paper label during storage at $30^{\circ}C$ can be considered as a potent method for maintaining the physiology of watermelon stalk.

The SOFA Score to Evaluate Organ Failure and Prognosis in the Intensive Care Unit Patients (중환자실에 입원한 환자의 장기부전 및 예후 평가를 위한 SOFA 점수체계의 의의)

  • Kim, Su Ho;Lee, Myung Goo;Park, Sang Myeon;Park, Young Bum;Jang, Seung Hun;Kim, Cheol Hong;Jeon, Man Jo;Shin, Tae Rim;Eom, Kwang Seok;Hyun, In-Gyu;Jung, Ki-Suck;Lee, Seung-Joon
    • Tuberculosis and Respiratory Diseases
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    • v.57 no.4
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    • pp.329-335
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    • 2004
  • Background : The Sequential Organ Failure Assessment (SOFA) score can help to assess organ failure over time and is useful to evaluate morbidity. The aim of this study is to evaluate the performance of SOFA score as a descriptor of multiple organ failure in critically ill patients in a local unit hospital, and to compare with APACHE III scoring system. Methods : This study was carried out prospectively. A total of ninety one patients were included who admitted to the medical intensive care unit (ICU) in Chuncheon Sacred Heart Hospital from May 1 through June 30, 2000. We excluded patients with a length of stay in the ICU less than 2 days following scheduled procedure, admissions for ECG monitoring, other department and patients transferred to other hospital. The SOFA score and APACHE III score were calculated on admission and then consecutively every 24 hours until ICU discharge. Results : The ICU mortality rate was 20%. The non-survivors had a higher SOFA score within 24 hours after admission. The number of organ failure was associated with increased mortality. The evaluation of a subgroup of 74 patients who stayed in the ICU for at least 48 hours showed that survivors and non-survivors followed a different course. In this subgroup, the total SOFA score increased in 81% of the non-survivors but in only 21% of the survivors. Conversely, the total SOFA score decreased in 48% of the survivors compared with 6% of the non-survivors. The non-survivors also had a higher APACHE III score within 24 hours and there was a correlation between SOFA score and APACHE III score. Conclusion : The SOFA score is a simple, but effective method to assess organ failure and to predict mortality in critically ill patients. Regular and repeated scoring enables patient's condition and clinical course to be monitored and better understood. The SOFA score well correlates with APACHE III score.

Treatment of Intracranial Meningioma with Linac Based Radiosurgery (뇌수막종에서 선형가속기를 이용한 방사선수술 효과)

  • Kay Chul Seung;Yoon Sei Chul;Chung Su Mi;Ryu Mi Ryung;Kim Yeon Sil;Suh Tae Suk;Choi Kyuho;Son Byung Chul;Kim Moon Chan
    • Radiation Oncology Journal
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    • v.19 no.2
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    • pp.81-86
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    • 2001
  • Prupose : To evaluate the role of linac based radiosurgery (RS) in the treatment of meningiomas, we retrospectively analyzed the results of clinical and follow up CT/MRI studies. Methods and Materials : From the 1988 July to 1998 April, twenty patients of meningioma had been treated with 6 MV linear accelerator based radiosurgery. Of the 20 patients, four $(20\%)$ were male and 16 $(80\%)$ were female. Mean age was 51 years old ($22\~78$ years old). Majority of intracranial location of tumor for RS were parasagittal and sphenoid wing area. RS was done for primary treatment in 6 $(30\%)$, postoperative residual lesions in 11 $(55\%)$ and regrowth after surgery in 3 $(15\%)$. Mean tumor volume was $5.72\;cm^3\;(0.78\~15.1\;cm^3)$ and secondary collimator size was 2.04 cm $(1\~3\;cm)$. The periphery of tumor margin was prescribed with the mean dose of 19.6 Gy $(9\~30\;Gy)$ which was $40\~90\%$ of the tumor center dose. The follow up duration ranged from 2.5 to 109 months (median 53 months). Annual CT/MRI scan was checked. Results : By the follow up imaging studies, the tumor volume was reduced in 5 cases $(25\%)$, arrested growth in 14 cases $(70\%)$, and increased size in 1 case $(15\%)$. Among these responsive and stable 19 patients by imaging studies, there showed loss of contrast enhancement after CT/MRI in four patients. In clinical response, nine $(45\%)$ patients were considered improved condition, 10 $(50\%)$ patients were stable and one $(5\%)$ was worsened to be operated. This partly resulted in necrosis after surgery. Conclusion : The overall control rate of meningiomas with linac based RS was $95\%$ by both imaging follow-up and clinical evaluation. With this results, linac based RS is considered safe and effective treatment method for meningioma.

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A Study on the Real Condition and the Improvement Directions for the Protection of Industrial Technology (산업기술 보호 관리실태 및 발전방안에 관한 연구)

  • Chung, Tae-Hwang;Chang, Hang-Bae
    • Korean Security Journal
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    • no.24
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    • pp.147-170
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    • 2010
  • This study is to present a improvement directions for the protection of industrial key technology. For the purpose of the study, the survey was carried out on the administrative security activity of 68 enterprises including Large companies, small-midium companies and public corporations. survey result on the 10 items of security policy, 10 items of personal management and 7 items of the assets management are as follows; First, stable foundation for the efficient implement of security policy is needed. Carrying a security policy into practice and continuous upgrade should be fulfilled with drawing-up of the policy. Also for the vitalization of security activity, arrangement of security organization and security manager are needed with mutual assistance in the company. Periodic security inspection should be practiced for the improvement of security level and security understanding. Second, the increase of investment for security job is needed for security invigoration. Securing cooperation channel with professional security facility such as National Intelligence Service, Korea internet & security agency, Information security consulting company, security research institute is needed, also security outsourcing could be considered as the method of above investment. Especially small-midium company is very vulnerable compared with Large company and public corporation in security management, so increase of government's budget for security support system is necessary. Third, human resource management is important, because the main cause of leak of confidential information is person. Regular education rate for new employee and staff members is relatively high, but the vitalization of security oath for staff members and the third party who access to key technology is necessary. Also access right to key information should be changed whenever access right changes. Reinforcement of management of resigned person such as security oath, the elimination of access right to key information and the deletion of account. is needed. Forth, the control and management of important asset including patent and design should be tightened. Classification of importance of asset and periodic inspection are necessary with the effects evaluation of leak of asset.

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Surgical Evaluation of Squamous Cell Carcinoma of the Lung (편평상피세포 폐암의 외과적 고찰)

  • An, Byeong-Hui;Mun, Hyeong-Seon;Na, Guk-Ju;Kim, Sang-Hyeong
    • Journal of Chest Surgery
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    • v.30 no.2
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    • pp.179-186
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    • 1997
  • The frequency of primary lung cancer is increasing compared to other cancer. Complete surgical resection is the most effective method of treatment, but it is limited to only 25 to 30 percent of patients after initial clinical presentation. The survival rate is different by the subtypes of carcinoma, stages, and general condition of patients. The author investigated the survival rate of 87 patients with squamous cell carcinoma of the lung after surgery. Age ranged from 31 to 73 years, with Lean 57.1) $\pm$ 7.15 and 80.5% (70 cases) was initially diagnosed at sixth and seventh decades. Male to female ratio was 8.9'1. Initial complaints were cough with sputum in 78.1%, weight loss in 31.0%, chest pain and discomfort in 29.9%, and hemoptysis in 24.1%. The location of the tumor was right side in 44.8% and left slde in 55.2% ; LUL in 39.1%, RLL in 20.7%, LLL in'16. 1%, RUL in 14.9% and RML in 9.2%. Stage I was 19.5%, stage II 25.3%, stage olla 54.1% and stage lIIb 1.1%. Operative procedures were as follow : pneumonectomy in 52.9%, lobectomy in 47.1%, sleeve upper lobectomy in 4 cases. Single mediastinal Iymph node involvement was observed in 17 cases, and multi-level mediastinal Iymph node involvement in 23 cases. Lower paratracheal Iymph node and subcarinal Lymph node were more frequently involved in right side lung cancer, with 8 and 10 cases, respectively and subaortic Iymph node was most frequently involved in left side lung cancer with 9 cases. Operative complications were hoarseness, wound infection and chylothorax in 7, 5 and 4 cases, respectively. The operative mortality was 2.2% and the cause of death was pulmonary edema. Postoperative follow-up period ranged from 1 month to 99 months with a mean of 29.95 $\pm$ 17.21 months. Overall one-year survival rate was 75.1 % and five-year survival rate was 29.8%. One-year and five-year survival rates were 93.7% and 52.4% for stage 1, 92.2% and 30.5% for st ge ll, and 61.2% and 17.4% for stage llla, respectively. These findings correlate survival rate with tumor size, mediastinal Iymph node metastasis and surgical resectability, and long-term survival can be expected with small sized tumor, absent mediastinal Iymph node metastasis and complete surgical resection.

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Research on the Reduction of Exposure Dose of a Patient Having a PET/CT Exam (PET/CT 검사 환자의 피폭선량 경감을 위한 연구)

  • Kim, Bong-Su;Pyo, Sung-Jai;Cho, Yong-Gyi;Shin, Chai-Ho;Cho, Jin-Woo;Kim, Chang-Ho
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.3
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    • pp.10-16
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    • 2009
  • Purpose: As the number of patients has increased since the installation of a PET/CT, we are now examining about 2500-3000 annually. We have realized that if we properly adjust a pitch under the same condition of a CT during a PET/CT exam, radiation quantity that reaches the patient can change. In order to reduce the exposure dose of a patient, the research examines a method of reducing the exposure dose of a patient by controlling the pitch during a PET/CT exam, viewing whether the adjustment of the pitch influences CT image and PET SUV. Methods: The equipment used is a Biograph Positron Emission Tomography (PET) Scanner (CT type: TRCT-240-130 (WCT-240-130)) of Siemens company. For the evaluation of exposure dose of a patient, we measured radiation quantities using a PTW-DIADOS 11003/1383, which is a CT radiation measurement instrument used by Siemens. We measured and analyzed the space resolutions of CT images caused by the change of pitches using an AAPM Standard Phantom in order to see how the adjustment of pitches influenced the CT images. In addition, in order to obtain SUVs caused by each change of pitches using a PET source made with a solid radioactive cylinder phantom, we confirmed whether the SUVs changed in the PET/CT images by calculating the SUVs of the fusion images caused by the change of pitches after obtaining CT and PET images and finishing the test. Results: 2slice CT scanner showed that radiation quantities largely dropped when pitches ranged from 0.7 to 1.3 and that the reduction of radiation quantities were smaller when pitches ranged from 1.5 to 1.9. That is, we found that the bigger pitch values are the smaller the radiation quantities of a patient are. Moreover, we realized that there is no change of SUVs caused by the increase of pitches and that pitch values do not influence PET SUVs and the quality of CT images. It is judged that using 1.5 as a pitch value contributes to the reduction of exposure dose of a patient as long as there is no problem in the quality of an image. Conclusions: When seeing the result of the research, hospital using a PET/CT should make an effort to reduce the exposure dose of a patient seeking pitch values appropriate for their hospital within the range in which there is no image distortion and PET SUVs are not influenced from pitches. We think that the research can apply to all multi-detectors having a CT scanner and that such a research will be needed for other equipments in the future.

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