• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.75-81
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• 2012

The purpose of this study was administered to the body for examination and treatment, high-energy radioactive isotope(F-18, I-131) in vitro discharge experiments. Increasing exposed dose of radiation to health professionals is caused by the increase of PET/CT use and a radioactive isotope. Therefore, the high-energy isotope F-18 and I-131 after administration about using Metabolite excretion was studied. As a results of this study, patients had plenty of fluids for testing and treatment alone administered radiopharmaceuticals can be more than twice as fast excretion induced emissions. Also was able to get a better image space to reduce the dose rate.

• Radiation Oncology Journal
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• 제7권2호
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• pp.299-303
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• 1989

Authors have developed highly reproducible calibration method for the Micro-Selectron HDR Ir-192 system (Nucletron, Motherland). The new jig has a 10cm radius circular hole in the $30cm{\times}30cm{\times}0.2cm$ acrylic plate, and 5F flexible bronchial tubes are attached around the hole. The source moves along the circle in the tubes and the ionization chamber is placed verticaly at the center of the circular hole (center of the jig). Dose distribution near the center was derived theoretically, and measured with the film dosimetry system. Theoretical calculation and measurement show the error margin below $0.1\%$ for 1mm or 2mm position deviation. We have measured at 12 and 24 points of circle with 1, 6, 11 and 21 second dwell time of source in order to calculate the activity of the source. Measurements have been repeated daily for 50 days. The accuracy and the reproducibility are below $1\%$ error margin. The half life of the source from our measurement is estimated $73.4\pm0.4$ days.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1998-2004
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• 2019

The Multi-Physics (MP) instrument is one of 20 neutron spectrometers planned in the China Spallation Neutron Source (CSNS). This paper presents a shielding calculation for the MP instrument using Monte Carlo codes MCNPX and FLUKA. First, the neutrons that escape from the CSNS decoupled water moderator and are delivered to the beam line of the MP instrument are calculated to use as the source term of the shielding calculation. Then, to validate the calculation method based on multiple variance reduction techniques, a cross check between MCNPX and FLUKA codes is performed by comparing the calculation results of the dose rate distribution on a simplified beam line model. Finally, a complete geometry model of the MP instrument is set up, and the primary parameters for the shielding design are obtained according to the calculated dose rate map considering different worst-case scenarios.

• 한국방사선학회논문지
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• 제9권5호
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• pp.323-329
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• 2015

이 연구는 금속쐐기필터를 대신하여 동적쐐기필터를 사용할 수 있을지에 대한 적정성 평가에 관한 것이다. 선형가속기에서 발생되는 엑스선 에너지는 6 MV, 10 MV로 상용화되어있다. 금속쐐기필터의 $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$에 각각 100, 200, 300, 400, 500, 600 선량율(MU/min)로 48번 조사하였고, 동적쐐기필터와의 비교를 위해 같은 조건으로 총 96번 조사하였다. 측정조건은 선원필름간 거리 100cm, 조사면 $10{\times}10cm$ 로 측정하였다. 현상된 필름을 스캔하여 선량분석프로그램으로 교정 후 분석하였고, 표준편차를 구해 선량율을 비교하였다. 동적쐐기필터는 선량, 산란선 및 치료시간을 감소시키며, 환자에 조사되는 선량이 적어 매우 유용하다. 동일한 조건에서 선량율에 따른 오차는 연관성이 없으므로 환자의 상황에 따라 고선량율의 치료를 사용하는 것도 가능할 것으로 생각된다.

• 대한기관식도과학회지
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• 제15권2호
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• pp.49-56
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• 2009

Purpose : To evaluate the treatment outcome for patients with locally advanced, unresectable esophageal cancer treated with relatively high dose radiation therapy(RT). Materials and Methods : From January 2000 to December 2008, 32 patients with locally advanced unresectable or medically inoperable esophageal cancer were treated with radiation therapy(RT) with or without concurrent chemotherapy. Ten patients were excluded from analysis because of distant metastasis and drop off. Patient distributions according to AJCC stages II, III IVa were 7(31.8%), 12(54.6%), 3(13.6%) respectively. The locations of tumor were cervical/upper thorax 3 (13.6%), mid thorax 13(59.1%), and lower thorax/abdominal 6(27.3%), respectively. Eleven patients received RT only, and 11 patients received cisplatin based concurrent chemoradiotherapy(CCRT). Median radiation dose was 65 Gy(range 57.6~72 Gy). Results : The median follow-up was 9.1 months(range 1.9~43.8 months). The response rates for complete response, Partial response, stable disease and Persistent disease were 6(27.3%), 11(50.0%), 4(18.2%) and 1(4.5%), respectively. Two patients(9.1%) suffered from esophageal stenosis and stents were inserted. Two patients(9.1%) had Grade 3 radiation pneumonitis and one of them expired due to acute respiratory distress syndrome(ARDS) at 36 days after completion of radiation therapy. The recurrence rate was 11(50.0%). The patterns of recurrence were persistent disease and local progression in 5(22.7%), local recurrence 3(13.7%) and concomitant local and distant recurrence in 3(13.7%). The overall survival(OS) rate was 32.1% at 2 years and 21.4% at 3 years(median 12.0 months). Disease free survival(DFS) rate was 17.3% at 2 and 3 years. All patients who had no dysphagia at diagnosis showed complete response after treatment and 100% OS at 3 years(p=0.0041). The OS for above 64.8 Gy group and 64.8 Gy or below group at 3 years were 60.6% and 9.1%(p=0.1341). The response to treatment was the only significant factor affecting OS(p=0.004). Conclusion : Relatively high dose radiation therapy in unresectable esophageal cancer tended to have a better outcome without increased complication rate. Further study with more patients is warranted to justify improved result.

• 한국임상약학회지
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• 제14권1호
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• pp.1-10
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• 2004

Studies of oxaliplatin, 5-fluorouracil and leucovorin in pretreated metastatic colorectal cancer showed that oxaliplatin dose intensity is important prognostic factor for objective response rates and progression-free-survival (PFS). To evaluate response rates, PFS and toxicity according to oxaliplatin dose intensity, we retrospectively analyzed data from patients with metastatic colorectal cancer received oxaliplatin,5-fluorouracil, leucovorin regimens. Sixty-three patients were reviewed in this study, 42 patients received low dose intensity oxaliplatin (LDI: $\leq85\;mg/m^2/2wks$) and 21 patients high dose intensity oxaliplatin (HDI: $>85\;mg/m^2/2wks$). Objective responses occurred in 10 $(47.7\%)$ HDI patients and 9 $(21.4\%)$ LDI patients (p = 0.014). Median PFS was 24.7 weeks in HDI group, with $45.1\%$ of HDI patients progression free at 6 months, and 20.5 weeks in LDI group, with $33.5\%$ of LDI patients progression free at 6 months (p = 0.344). Increased oxaliplatin dose intensity was not associated with neutropenia, thrombocytopenia, neuropathy, nausea and vomiting. This study showed that oxaliplatin dose intensification significantly improves objective response rate in pretreated metastatic colorectal cancer without increasing severe toxicity.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3383-3387
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• 2023

A new dyed polyvinyl alcohol (PVA) film dosimeter based on 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MMT) tetrazolium dye is proposed in this study for measuring high gamma radiation dose. Gamma cell irradiator that contains Co-60 gamma-ray source was used to expose the novel MMT-PVA films to different doses up to 25 kGy. The changed in optical property of irradiated and unirradiated films were characterized by UV-Vis spectrophotometer. The results show that the dose sensitive and the linear range of irradiated films were increased considerably with increase of MMT concentration from 1 to 5 mM. The dose response of dyed PVA film changed substantially with changing relative humidity (12-74%) as well as irradiation temperature (10-40 ℃). The absorbance of the unirradiated films does not change up to 10 days in dark while a significant increase in their absorbance was reported for similar films under fluorescent light. The irradiated dosimeters that kept in dark showed a perfect stability for 54 days. It was found that no obvious impact of dose rate on the irradiated MMT-PVA film dosimeters.

• 약학회지
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• 제36권4호
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• pp.291-302
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• 1992

Effects of Zinc chloride on the immune responses were studied in ICR mice. ICR male mice were divided into 5 groups(10 mice/group) and Zinc chloride at doses of 0.3, 1.2, 4.8 and 19.2 mg/kg were orally administered to ICR male mice once a day for three weeks. Mice were sensitized and challenged with sheep red blood cells(S-RBC). The results of this study were summarized as follows; (1) Zinc chloride significantly increased the body weight rate, the weight ratios of spleen and thymus to body weight and the number of circulating leukocyte, but significantly decreased them at the high dose of it, and increased dose-dependently the weight ratio of liver to body weight. (2) Zinc chloride significantly increased hemagglutination titer, Arthus reaction and plaque forming cell related to humoral immunity, but significantly decreased them at the high dose of it. (3) Zinc chloride significantly increased delayed-type hypersensitivity reaction and rosette forming cell related to cellular immunity, but significantly decreased them at the high dose of it. (4) Zinc choride significantly enhanced phagocytic activity, but significantly decreased according to the increase of its dose. These results suggest that high dose of zinc chloride decreased humoral, cellular and non-specific immune responses.

• Radiation Oncology Journal
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• 제33권4호
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• pp.301-309
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• 2015

Purpose: To identify prognostic factors for disease progression and survival of patients with extracranial oligometastatic breast cancer (EOMBC), and to investigate the role of radiation therapy (RT) for metastatic lesions. Materials and Methods: We retrospectively reviewed the medical records of 50 patients who had been diagnosed with EOMBC following standard treatment for primary breast cancer initially, and received RT for metastatic lesions, with or without other systemic therapy between January 2004 and December 2008. EOMBC was defined as breast cancer with five or less metastases involving any organs except the brain. All patients had bone metastasis (BM) and seven patients had pulmonary, hepatic, or lymph node metastasis. Median RT dose applied to metastatic lesions was 30 Gy (range, 20 to 60 Gy). Results: The 5-year tumor local control (LC) and 3-year distant progression-free survival (DPFS) rate were 66.1% and 36.8%, respectively. High RT dose (${\geq}50Gy_{10}$) was significantly associated with improved LC. The 5-year overall survival (OS) rate was 49%. Positive hormone receptor status, pathologic nodal stage of primary cancer, solitary BM, and whole-lesion RT (WLRT), defined as RT whose field encompassed entire extent of disease, were associated with better survival. On analysis for subgroup of solitary BM, high RT dose was significantly associated with improved LC and DPFS, shorter metastasis-to-RT interval (${\leq}1month$) with improved DPFS, and WLRT with improved DPFS and OS, respectively. Conclusion: High-dose RT in solitary BM status and WLRT have the potential to improve the progression-free survival and OS of patients with EOMBC.

• 한국방사선학회논문지
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• 제9권2호
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• pp.121-124
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• 2015

디지털유방촬영술은 유방암의 조기진단에 매우 중요하다. 그러나 방사선량을 과다하게 피폭하는 경우에는 환자에게 유방암의 발생확률을 증가 시킬 수 있다. 본 연구에서는 제조사별 관전압과 타깃-필터의 변화에 따른 흡수선량률과 화질을 분석하고 최적의 타깃-필터조합을 찾아 환자의 피폭선량 변화를 확인하고자 하였다. 각 제조사별 흡수선량률에서는 Mo/Mo를 사용할 때 가장 낮게 측정되었다. 대조도는 Mo/Rh를 사용할 때 우수하게 나타났다. SNR은 Mo/Mo(Siemens), Mo/Rh(Hologic), Mo/Rh(GE) 에서 우수하게 나타났다. 본 연구의 결과는 최대의 환자선량감소, 고대조도 영상획득, 높은 SNR 영상획득등 사용목적에 따라 타깃-필터 선택 시 좋은 참고지표가 될 것이다.