• Nuclear Engineering and Technology
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• 제56권1호
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• pp.56-63
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• 2024

In high radiation fields, gamma cameras suffer from pulse pile-up, resulting in poor energy resolution, count losses, and image distortion. To overcome this problem, various methods have been introduced to reduce the size of the aperture or pixel, reject the pile-up events, and correct the pile-up events, but these technologies have limitations in terms of mechanical design and real-time processing. The purpose of this study is to develop a real-time gamma camera to evaluate the radioactive contamination in high radiation fields. The gamma camera is composed of a pinhole collimator, NaI(Tl) scintillator, position sensitive photomultiplier (PSPMT), signal processing board, and data acquisition (DAQ). The pulse pile-up is corrected in real-time with a field programmable gate array (FPGA) using the start time correction (STC) method. The STC method corrects the amplitude of the pile-up event by correcting the time at the start point of the pile-up event. The performance of the gamma camera was evaluated using a high dose rate ¹³⁷Cs source. For pulse pile-up ratios (PPRs) of 0.45 and 0.30, the energy resolution improved by 61.5 and 20.3%, respectively. In addition, the image artifacts in the ¹³⁷Cs radioisotope image due to pile-up were reduced.

• Radiation Oncology Journal
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• 제12권1호
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• pp.91-98
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• 1994

Purpose: Despite apparently complete resection of cancer of the rectum, local recurrence rate was high. Radiation therapy has been used either alone or in combination with chemotherapy as an adjunct to surgery to reduce the risk of recurrence. This study was designed to evaluate the prognostic factors, survival rate and local recurrence rate of the rectal cancer who had received postoperative radiation therapy by retrospective analysis. Method: From 1982 to 1990, 63 patients with cancer of the rectum surgically staged as B2 or C disease received postoperative adjuvant radiation therapy after curative resection of tumor for cure. Postoperative radiation therapy was given to the whole pelvis(mean dose: 5040 cGy in 5-6weets) and perineum was included in irradiated field in case of abdominoperineal resection. Results: Three-year actuarial survival rate was 73.2$ \% $ overall, 87.7$ \% $ in stage B2+3 and 62.9$ \% $ in stage C2+3. Three-year disease-free survival rate was 69.5$ \% $ overall, 87.7$ \% $ in stage B2+3 and 56.8$ \% $ in stage C2+3, Three-year disease-free survival rate in anterior resection was 77.8$ \% $ and 44.4$ \% $ in abdominoperineal resection. The local recurrence rate was 15.9$ \% $ and distant failure rate was 20.6$ \% $. Severe late complication was small bowel obstruction in 6 patients and surgery was required in 4 patients(6.3$ \% $). The prognostic factors were stage(p=0.0221) and method of surgery(p= 0.0414) (anterior resection vs abdominoperineal resection). Conclusion: This study provides evidence supporting the use of postoperative radiation therapy for reducing the local recurrence rate in patients who have had curative resection of rectal cancer with involvement of perirectal fat or regional nodes or both(stage B2 and C).

• Journal of Chest Surgery
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• 제19권2호
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• pp.197-208
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• 1986

Propranolol is one of clinically useful antiarrhythmic agents and electrophysiologically classified as group II. And the negative inotropic effect which is not related to adrenolytic effect has been demonstrated with high concentration of propranolol. On the other hand, it has been well known that the calcium plays a central role in excitation-contraction coupling process of myocardium and also in electrophysiological changes of cell membrane. Author studies the effect of propranolol on calcium uptake and release in sarcoplasmic reticulum and mitochondria prepared from porcine myocardium to investigate the mechanism of action of propranolol on myocardium. The results are summarized as follow: 1] The maximum Ca++-uptake of sarcoplasmic reticulum is inhibited by propranolol in a dose dependent manner. 2] The release of calcium from sarcoplasmic reticulum is not affected by propranolol but with higher than 1x10-3 M of propranolol, rate of calcium release from sarcoplasmic reticulum is decreased. 3] Propranolol inhibits the maximum uptake and uptake rate of calcium in mitochondria non-competitively. [Ki = 6.21 x 10-4 M] 4] The rate of Na+ induced calcium release from mitochondrion shows a function of [Na+]2 and is inhibited by propranolol with the concentration significantly lower than that affect the calcium uptake in sarcoplasmic reticulum and in mitochondria [Ki = 2.91 x 10-5 M]. These results suggest that propranolol affects the intracellular calcium homeostasis which may considered to be one of the mechanism of action of propranolol on myocardium.

• Radiation Oncology Journal
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• 제6권2호
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• pp.295-300
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• 1988

Chordoma is a malignant tumor arising from the primitive notochord involving the axial skeleton. It usually occurs at sacrococcygeal and besisphenoidal area but only rarely does at other vertebral areas, especially at the thoracic vertebrae. It has a slow growth rate and is locally aggressive with an extremely high rate of local recurrence. Either surgery or radiation alone often fails to cure the disease and the local failure is the main cause of treatment failure and death. Overall 5 year survival rate is less than $10\%$. Useful palliation or occasional cure can be obtained by the combination of surgery and radiotherapy. After incomplete resection, the tumor requires radiation dose of 7,000 cGy or more over 6-7 weeks for local control. Tumor regression is slow in response to irradiation and continuation of the regression for several months after completion of RT is not unusual. We report a case of chordoma of the thoracic vertebra, the site of extreme rarity, which showed good local control after partial resection and radiation therapy. He is well and alive without any evidence of recurrence after 13 months of treatment with near complete tumor regression.

• 한국환경보건학회지
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• 제19권2호
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• pp.1-9
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• 1993

In public water supply systems, Alum and/or PAC being used as a coagulant. It is well known that their use increased frequently the concentration of residual aluminum in filtered water upon operating conditions. This study was conducted to find the optimum conditions that both the concentration of residual aluminum and turbidity are minimized by changing such factors as pH, temperature, alum dosage, mixing rate, alkalinity and hardness. The results can be summarized as follows: The pH values for the minimum concentration of residual aluminum and turbidity as a given experimental condition were found at pH 6 and pH 7 respectively, the apparent clarity was best at pH 8. The floc settling rate was the greatest at pH 6.5, but the turbidity was high at the same condition. The more alum dosage, the higher the concentration of residual aluminum. However the alum dosage less than 15 mg/l tend to decrease in turbidity. Restabilization and enmeshment occurred near 15 mg/l and 20 mg/l of alum dose respectively. With the increase of mixing rate (rapid and slow), the concentration of residual aluminum and turbidity are increased and the same trend was found in increment of mixing time. At low water temperature, the concentration of residual aluminum was decreased, but turbidity was increased. It was confirmed that alkalinity had an effect on the coagulation efficiency, but hardness did not.

• Radiation Oncology Journal
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• 제19권4호
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• pp.312-318
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• 2001

목적 : 고위험 유방암 환자의 수술 후 방사선치료 후 국소 재발율, 생존율 및 예후인자를 후향적 분석하여 방사선치료의 역할을 규명하고자 하였다. 대상 및 방법 : 1984년부터 1995년까지 유방암으로 변형 근치적 유방절제술 후 종양의 크기가 4 cm 이상이거나, 4 cm 미만이나 액와 림프절의 전이가 있는 환자 중 방사선치료를 완료한 48명을 대상으로 하였다. 중앙 연령은 47세 ($31\~79$세)이었으며, 종양의 크기가 2 cm미만 1명, $2\~5\;cm$ 15명, 5 cm이상이 32명이었다. 액와림프절에 전이된 환자는 32명이었다. 흉벽과 국소림프절에 방사선치료받은 환자는 42명, 흉벽만 받은 환자는 6명이었으며 방사선량은 1일 1회(1.8 Gy)로 총 선량은 50.4 Gy이었다. 48명 중 18명$(38\%)$은 5-FU를 기본으로 하는 항암화학요법을 방사선치료 전 혹은 후에 투여하였다. 중앙 추적기간은 61개월이었다. 결과 : 국소 재발율은 $8\%$, 원격전이율은 $14\%$이었다. 전체환자의 5년 생존율은 $63\%$, 무병생존율은 $62\%$이었으며 중앙생존기간은 67개월이었다. 병기에 따른 5년 생존율은 IIB는 $70\%$, IIIA는 $58\%$이었으며, 생존율에 미치는 예후인자는 병기이었다(p=0.0076). 결론 : 고 위험군의 유방암 환자의 수술 후 방사선치료는 국소재발율은 감소시키고 생존율을 향상시킬 수 있으며, 생존율에 영향을 주는 인자는 병기이었다.

• Radiation Oncology Journal
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• 제11권2호
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• pp.347-354
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• 1993

This is a retrospective analysis of 67 patients with histologically proven invasive carcinoma of uterine cervix treated with surgery followed by adjuvant radiotherapy at Inje University Seoul Paik Hospital between october 1983 and september 1991, Postoperative radiotherapy was carried out in patients with high risks of locoregional recurrence such as positive pelvic lymph node (38 pts), large tumor size more than 3 cm (22 pts), cervical stromal invasion more than 2/3 (46 pts), parametrial involvement (9 pts), positive resection margin (14 pts), endo/myometrial extension (10 pts), and angiolymphatic invasion (13 pts). Stage I A, I B, and IIA were 2 $(3\%),$ 39 $(58.2\%),\;and\;26\;(38.8\%),$ respectively. Median follow-up period was 48 months with ranges from 13 to 115 months. All 67 patients were treated externally with standard pelvic field with radiation dose ranging from 4080 to 6120 cGy in 4~6 weeks period of time. Of these, 45 patients received intracavitary radiotherapy. The overall survival rate and disease free survival rate at 5-year were $88.0\%\;and\;82.1\%,$ respectively. The survival rates by stage were $87.1\%$ in IB and $88.4\%$ in IIA. Local control rate was $80.6\%(58\;pts).$ The treatment failure was noted in 12 of 67 patients $(17.9\%):$ locoregional failure in $7(10.4\%),$ distant metastasis in 3 $(4.5\%),$ and locoregional and distant metastasis in $2(3\%),$ The univariate analysis of prognostic factors disclosed endo/myometrial extension as a significant factor of survival and recurrence $(70.0\%\;vs\;91.1\%\;P<0.05\;&\;30.0\%\;vs\;15.8\%,\;respectively).$ The complication of postoperative radiothrapy was not significant and all patient were well tolerated. In conclusion, postoperative radiotherapy in patients with high risks of locoreginal recurrence is relatively well tolerated and it gives significantly improved survival rate especially in patients with positive lymph nodes, bulky tumor size $(\geqq3\;cm),$ parametrial involvement, cervical stromal invasion more than 2/3, positive resection margin and angiolymphatic invasion.

• Radiation Oncology Journal
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• 제13권2호
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• pp.181-189
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• 1995

목적: 국소적으로 진행된 자궁경부암의 치료는 방사선 단독요법이 주 치료였으나 근래에는 좀 더 완치율을 높이기위해 약물치료와 병행하여 방사선치료가 시행되고 있다. 저자들은 45명의 방사선 단독요법과 77명의 항암화학과 방사선의 병용요법의 치료성적을 후향적으로 분석하였다. 방법: 1985년 1월부터 1991년 12원까지 한양대학병원 치료방사선과에서 외부방사선 및 강내방사선치료를 받은 환자 122명을 대상으로 후향적으로 분석하였다. 34명은 ICR 1회, 77명은 ICR 2회, 11명은 고선량 강내근접 방사선치료를 받았다. 연령분포는 29세부터 81세였고, 중앙연령은 58세였다. 추적기간은 5개월에서 117개월(5명이 34개원 미만)로 중앙값은 60개월이었다. 조직병리상 111명이 squamous cell ca, 5명이 large cell ca, 4명이 adenoca, 2명이 adenosquamous cell ca였다. FIGO 병기로 IB $6명(4.9\%),$ IIA 11명$(9.0\%),$ IIB 37명$(30.3\%),$ IIIA 3명$(2.5\%),$ IIIB 63명$(51.6\%),$ IVA 2명$(1.6\%)$이었다. 항암화학요법을 병용한 환자 77명중 36명은 VBP, 39명은 cispiatin 과 5-FU, 2명은 5-FU 제제로 치료받았다. 결과: 외부방사선조사량 3900 cGy에서 5500 cGy를 받은환자에서 61명$(50\%)$이 육안적으로 완전관해를보였다. 5년 및 9년 생존율은 전체환자에서 각각 $57.8\%,\;53.9\%$였고 방사선 단독요법의 5년 생존율이 $63.1\%,$ 방사선과 항암화학복합요법의 5년 생존율은 $55.9\%$였다. 항암제 VBP(vinblastin, bleomycin, cisplatinum)로 치료받은 환자에서 5년 생존율이 $63\%$이고 cisplatin으로 치료받은 환자는 $50\%$이나 통계적인 유의성은 없었다. ICR 회수에따른 5년 생존율은 1회 ICR에서 $36.5\%,$ 2회 ICR에서 $67\%$였다. 방사선단독요법으로 치료받은 환자중 A point에 8000 cGy이상 받은 환자에서 5년 생존율이 $91.4\%$이었고 8000 cGy 미만 환자는 $27.2\%$로 통계적으로 유의한 생존율의 향상을 보였다(p<0.01). 항암화학요법으로 치료받은 환자는 A point의 dose에 따른 생존율의 차이를 보dl지 않았으며(<8000 cGy $55.6\%\;vs\;<=8000\;cGy\;55.7\%)$ 1회의 ICR 과 2회의 ICR의 5년 생존율에도 큰 차이가 없었다$(50\%\;vs\;56.8\%).$ 병변크기가 3cm 이상인 환자에서 방사선 단독치료법과 항암화학치료법과의 5년 생존율의 차이가 없었다$(48.9\%\;vs\;48.7\%).$ 초기 병변에서 항암화학치료를 받지않은 군과 받은 관의 5년 생존율은 $60\%$와 $78\%$이나 숫자가 매우적어 의미가 없었고 진행된병기에서 5년 생존율은 방사선 단독군이 조금 좋았으나 통계적 유의성은 없었다$(62.6\%\;vs\;53.6\%)$ (p>0.05). 결론: 본 연구결과 방사선치료에 항암화학 병용은 생존율향상을 시키지 못하였다. 방사선단 독요법이 국소적으로 진행된 환자에 치료방법이며 A point에 8000 cGy이상 받은환자에서 생존율이 높았고 항암화학 병용요법 치료에서는 A point의 방사선양이 생존율에 영향을 미치지 않았다.

• Radiation Oncology Journal
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• 제19권1호
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• pp.74-80
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• 2001

목적 : 강내에 발생된 종양치료용 원통형 전자선 조사기구(Electron cone)는 기하학적으로 강내벽에 위치한 종양치료에 부적당하므로 후방 또는 측면방향으로 산란되는 전자선을 이용하여 체강 내벽점막 등에 발생된 종양을 효과적으로 치료할 수 있는 산란전자선 치료방법을 개발하고자 한다. 강내조사기구내에 전자선 입사방향에 수직 또는 일정한 각도의 산란판을 배치하여 측면방향으로 산란전자선을 방출시키는 강내 측면조사기구를 제작하고 산란판의 제원과 전자선 에너지에 따라 산란방출된 산란선의 특성과 조직내 선량분포를 측정 평가하였다. 새상 미 방법 : 외부조사용 전자선조사기구(Electron cone) 대신에 강내 삽입용 전자산란선 조사통(Intracavitary backscatter electron cone)과 이를 콜리메이터와 연결시킬 수 있는 차폐연결기구(Shielded electron device)를 고안하였다. 산란전자선 조사기구는 직경이 $2\~3\;cm$이고 길이가 25 cm인 금속(내식강)원통을 이용하였으며 입구에서 20 cm위치에 산란판을 부착시키고 원통 측면에 직경 $1\~2\;cm$의 산란선 방출구를 제작하였다. 산란판은 $2\~10\;mm$의 연판을 사용하였으며, 오제전자와 특성 엑스선을 제거하기 위하여 주석, 구리, 알루미늄판 등을 부착시켰으며 종양위치를 관찰할 수 있도록 표면을 처리하였다. 고에너지 방사선치료용 선형가속기(Clinac 2100C/D)에서 발생된 $6\~12\;MeV$ 에너지의 전자선을 이용하였으며 선량측정은 평행평판형 전리상(Markus chamber, PTW 23343)을 조직등가 팬텀(Polystyrene)에 삽입하여 측정하였다. 전자산란선의 에너지분포는 Monte Carlo (EGS4) 계산으로 예측하였으며 조직내 선량분포는 필름 흑화도(X-Omat V, Wellhofer 700i)에 의하여 측정하였다. 결과 : 전자선 입사에너지가 6 MeV일 때 전자산란선의 평균 에너지는 약 1.5 MeV 이었으며 산란각이 클수록 에너지는 줄어들었다. 입사 전자선 에너지 6 MeV 에서 산란판의 각도 $30^{\circ},\;45^{\circ}$ 에 따른 최대선량지점은 산란선 방출구의 중심에서 각각 5 mm 및 -10 mm지점의 표면에서 발생되며 입사전자선에 대한 전자산란선의 선량비는 약 $8.5\%$ 내외로 측정되었다. 입사전자선에너지 6 MeV에서 산란판각도 $45^{\circ},\;60^{\circ}$에 의한 $50\%$의 심부선량분포는 각각 6 mm와 7 mm 깊이에 도달하였으며 입사에너지 증가에 비례하였다. 결론 : 전자선 후방산란의 특성을 연구하고 이를 인체 강내 측방 점막부위에 발생한 종양을 효과적으로 치료할 수 있는 강내 전자산란선 조사통을 고안 제작 하였다. 시험용으로 제작한 전자산란선 조사기구를 이용하여 전자선 에너지와 산란판의 각도에 따른 산란선의 선량비율과 심부율을 측정하였다. 구강, 자궁, 직장 등 강내측벽 점막 등에 발생된 악성종양의 모양과 깊이에 가장 적당한 입사 에너지, 산란판의 각도, 산란창구 및 조사각도를 선택함으로서 방사선치료방법을 향상시킬 수 있을 것이라고 기대된다.

• 한국작물학회지
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• 제53권4호
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• pp.434-439
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• 2008

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.