• 한국융합학회논문지
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• 제9권7호
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• pp.87-93
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• 2018

본 연구는 핵의학과에서 많이 사용하고 있는 $^{99m}Tc$, $^{123}I$, $^{201}Tl$, $^{18}F$, $^{13}1I$를 비스무트 차폐체에 투과시킨 후 방사성동위원소의 종류와 측정 거리변화에 따라 차폐율을 알아보고자 하였다. 실험을 위해 납당량 0.25 mmPb, 비스무트 차폐체 6장을 두께가 두꺼워 질수록 1.50 mm까지 한 장씩 겹쳐 사용하였고, 거리를 30 cm, 50 cm, 100 cm로 두고 투과선량을 측정하였다. 그 결과 두께가 두꺼워질수록 차폐율이 높게 측정되었고 거리를 멀리할수록 측정값은 작아졌다. $^{99m}Tc$보다 $^{123}I$와 $^{201}Tl$의 차폐율이 가장 높게 나타나 차폐효과가 우수한 것을 확인하였고, $^{18}F$와 $^{131}I$는 고에너지와 ${\beta}$선으로 인해 차폐체가 없을때보다 차폐체가 있을때 차폐효과가 떨어지는 것으로 나타났다. 실험결과를 참고하여 방사성동위원소의 종류에 따라 비스무트 차폐체를 사용한다면 핵의학 종사자들의 피폭 저감화와 피폭관리 방안에 도움을 줄 수 있을 것으로 생각된다.

• 대한방사선기술학회지:방사선기술과학
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• 제46권2호
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• pp.141-149
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• 2023

The Korea Institute of Radiological and Medical Sciences plans to produce ²²⁵Ac, a therapeutic radio-pharmaceutical for precision oncology, such as prostate cancer. Radon, a radioactive gas, is generated by radium, the target material for producing ²²⁵Ac. The radon concentration is expected to be about 2000 Bq·m^-3. High-concentration radon-generating facilities must meet radioactive isotope emission standards by lowering the radon concentration. However, most existing studies concerning radon removal using activated carbon filters measured radon levels at concentrations lower than 1000 Bq·m^-3. This study measured ²²²Rn removal of coconut-based activated carbon filter under a high radon concentration of about 2000 Bq·m^-3. The ²²²Rn removal efficiency of activated carbon impregnated with triethylenediamine was also measured. As a result, the ²²²Rn removal amount of the activated carbon filter showed sufficient removal efficiency in a ²²²Rn concentration environment of about 2000 Bq·m^-3. In addition, despite an expectation of low radon reduction efficiency of Triethylenediamine-impregnated activated carbon, it was difficult to confirm a significant difference in the results. Therefore, it is considered that activated carbon can be used as a radioisotope exhaust filter regardless of whether or not Triethylenediamine is impregnated. The results of this study are expected to be used as primary data when building an air purification system for radiation safety management in facilities with radon concentrations of about 2000 Bq·m^-3.

• Journal of Korean Neurosurgical Society
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• 제45권1호
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• pp.1-4
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• 2009

Objective : In the present study, the authors investigated the clinical and imaging features as well as the therapeutic outcomes of SIH (spontaneous intracranial hypotension) patients. Methods : A retrospective review of 12 SIH patients was carried out. The diagnostic work-up included lumbar tapping and measurement of CSF opening pressure, radioisotope cisternography, brain and spinal magnetic resonance imaging (MRI), and computed tomography (CT) myelography. Autologous epidural blood patching was performed in patients who did not respond to conservative therapies, including analgesics, steroids, hydration and rest. Results : Typical postural headache was found in 11 (91%) patients. Nine (75%) patients showed pachymeningeal enhancement on their initial T1-weighted MR images. The CSF opening pressure was less than 60 mm$H_2O$ in 9 of 11 patients. Autologous epidural blood patching was performed in 7 patients, and all of them showed good responses. Conclusion : SIH can present with various clinical presentations and neuroimaging findings. Autologous epidural blood patching is thought to be the treatment of choice for patients with SIH.

• 한국의학물리학회지:의학물리
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• 제32권2호
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• pp.25-39
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• 2021

Brachytherapy, along with external beam radiation therapy (EBRT), is an essential and effective radiation treatment process. In brachytherapy, in contrast to EBRT, the radiation source is radioisotopes. Because these isotopes can be positioned inside or near the tumor, it is possible to protect other organs around the tumor while delivering an extremely high-dose of treatment to the tumor. Brachytherapy has a long history of more than 100 years. In the early 1900s, the radioisotopes used for brachytherapy were only radium or radon isotopes extracted from nature. Over time, however, various radioisotopes have been artificially produced. As radioisotopes have high radioactivity and miniature size, the application of brachytherapy has expanded to high-dose-rate brachytherapy. Recently, advanced treatment techniques used in EBRT, such as image guidance and intensity modulation techniques, have been applied to brachytherapy. Three-dimensional images, such as ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography are used for accurate delineation of treatment targets and normal organs. Intensity-modulated brachytherapy is anticipated to be performed in the near future, and it is anticipated that the treatment outcomes of applicable cancers will be greatly improved by this treatment's excellent dose delivery characteristics.

• Journal of Radiation Protection and Research
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• 제15권2호
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• pp.113-122
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• 1990

원자력병원에 설치된 MC-50 의학용 싸이클로트론은 4년간의 장비 도입 계획, 장비 인수 및 설치 그리고 빔 특성조사를 거쳐서 1986년 11월부터 가동을 시작하였다. MC-50 싸이클로트론은 현재 중성자치료 및 방사성 동위원소 생산에 이용되고 있다. 1989년 12월 현재, 중성자선 치료는 총 179명(1852 sessions)의 환자에서 시행되었다. 핵의학 분야에 이용되는 방사성 동위원소의 생산은 표적운반, 표적용융, 빔 진단 그리고 화학적 처리과정에 관한 문제들을 해결하기 위한 다각적인 연구를 거친 후 1989년 3월부터 시작하였다. 이 논문은 중성자 치료와 동위원소 생산에 이용된 MC-50 싸이클로트론의 운영 현황 및 장비의 특성에 대하여 기술하였으며, 또한 1989년도의 운영결과 및 제반 문제점들을 요약하였다. 1989년도 총 운전시간은 1252.5시간이었으며 이 중 중성자 치료에 400시간을 이용하였다(599 sessions). 동위원소 생산에는 832.5시간을 이용하여 총 1695mCi(Ga-67 : 1478mCi, Tl-201 : 107 mCi, I-123 : 25mCi, In-111 : 85mCi)를생산하였다. 빔 특성실험 및 기타 연구에는 20시간을 이용하였다. 1989년도의 가동율은 88.2%이었으며 전년도의 71.0%에 비하여 현저히 향상되었다.

• Nuclear Engineering and Technology
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• 제21권3호
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• pp.216-222
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• 1989

원자력병원에 설치되어 있는 MC-50 싸이클로트론은 중성자 치료와 의학용 동위원소 생산을 위해 가동중에 있다. 본 논문에서는 MC-50의 설계 특징, 기계적 구조, 가동 특성에 대하여 기술하고 있다. 본 싸이클로트론의 최적 가동 조건은 반복적인 운전에 의해 결정되었으며, 내부 빔의 성능은 싸이클로트론 반경의 함수로서 내부 빔의 세기 및 공간 분포 측정을 통해 조사되어졌다. 일상적으로, 인출효율이 61%일 때 40$\mu$A세기의 50 MeV 양성자 빔을 얻었다.

• 대한방사성의약품학회지
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• 제8권1호
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• pp.25-32
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• 2022

Malignant melanoma has an aggressive nature and high metastatic potential that result in one of the highest cancer mortality rates. Over the past three decades, primary and metastatic melanoma incidence has rapidly increased. The recent advances in diagnostic technology have shown promise, but there is still an enormous need for specific detection methods to diagnose malignant melanoma. Positron emission tomography can visualize a particular biomarker of malignant melanoma and promise a noninvasive image of micrometastases. However, the development of PET radiopharmaceuticals remains necessary for diagnosing malignant melanoma by using positron emission tomography. In this review, the history and a general overview of PET radionuclide labeled benzamide derivatives, including their radiosynthesis, in vivo characterization, and evaluation, are provided as imaging agents for malignant melanoma.

• 대한핵의학회지
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• 제37권1호
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• pp.43-52
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• 2003

Microarray technology allows the simultaneous analysis of gene expression patterns of thousands of genes, in a systematic fashion, under a similar set of experimental conditions, thus making the data highly comparable. In some cases arrays are used simply as a primary screen loading to downstream molecular characterization of individual gene candidates. In other cases, the goal of expression profiling is to begin to identify complex regulatory networks underlying developmental processes and disease states. Microarrays were originally used with ceil lines or other simple model systems. More recently, microarrays have been used in the analysis of more complex biological tissues including neural systems and the brain. The application of cDNA arrays in neuropsychiatry has lagged behind other fields for a number of reasons. These include a requirement for a large amount of input probe RNA In fluorescent-glass based array systems and the cellular complexity introduced by multicellular brain and neural tissues. An additional factor that impacts the general use of microarrays in neuropsychiatry is the lack of availability of sequenced clone sets from model systems. While human cDNA clones have been widely available, high qualify rat, mouse, and drosophilae, among others are just becoming widely available. A final factor in the application of cDNA microarrays in neuropsychiatry is cost of commercial arrays. As academic microarray facilitates become more commonplace custom made arrays will become more widely available at a lower cost allowing more widespread applications. in summary, microarray technology is rapidly having an impact on many areas of biomedical research. Radioisotope-nylon based microarrays offer alternatives that may in some cases be more sensitive, flexible, inexpensive, and universal as compared to other array formats, such as fluorescent-glass arrays. In some situations of limited RNA or exotic species, radioactive membrane microarrays may be the most practical experimental approach in studying psychiatric and neurodegenerative disorders, and other complex questions in the brain.

• 대한방사성의약품학회지
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• 제8권2호
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• pp.77-85
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• 2022

The Td05 and Sgc8c, DNA-based aptamers, are well-known to target internalized surface markers (IGHM and PTK7) of Burkitt's lymphoma and acute lymphoblastic leukemia (ALL). Thus, Td05 and Sgc8c labeled with metallic radioisotope ⁶⁴Cu can be evaluated as potential diagnostic PET imaging agents. In this study, we modified the carbon chain length of the last adenosine of aptamer (n = 3, 6, 12) to increase tumor cell uptake and select the best candidate among six types of aptamer analogues and one adenosine of aptamer. After labeling of ⁶⁴Cu, [⁶⁴Cu]Cu-DOTA-aptamer analogues were evaluated in vitro studies (serum stability, Log P values, cell uptake, biodistribution). Then, we evaluate in vivo PET imaging study for two candidates (⁶⁴Cu-DOTA-C12-Sgc8c, ⁶⁴Cu-DOTA-C6-Td05). PET images clearly visualize tumors at 24 h post-injection rather than at an early time point and the tumor-to-background ratio also increases at the delay time point. ⁶⁴Cu-DOTA-C12-Sgc8c and ⁶⁴Cu-DOTA-C6-Td05 could be used as potential radiotracers for lymphoma.

• 핵의학기술
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• 제17권2호
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• pp.53-58
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• 2013

본 연구에서는 각기 다른 에너지의 방사성동위원소를 이용하여 CT를 기초로 한 attenuation correction (AC)과 scatter correction (SC)을 적용했을 때 영상의 질을 비교분석하고 영상보정기법의 유용성에 대해 알아보고자 하였다. Resolution 평가를 위해 사용된 spatial resolution phantom 내부에 물을 채우고 각각의 동위원소 $^{99m}Tc$ (140 keV, 2.22 kBq), $^{201}Tl$ (70 keV, 2.22 kBq), $^{131}I$ (364 keV, 2.22 kBq)을 line에 주입하여 제작하였다. Contrast 평가를 위해 이용한 Jaszczak phantom은 배후방사능과 열소원통의 비율이 1:8이 되도록 각각의 동위원소를 주입하여 제작하였다. GE Infinia Hawkeye4 SPECT/CT (GE Medical System, USA)로 영상을 획득하고, non-correction (NC), AC, SC, AC와 SC가 동시에 적용된(ACSC) 4가지 조건으로 OSEM (2 iterations, 10 subsets)을 이용하여 영상을 각각 재구성하였다. FWHM값은 paired samples t-test를 통하여 유의수준 관계를 분석하였고, percent contrast (%)값은 MATLAB (Ver.7.0)$^{(R)}$과 MRIcro$^{(R)}$를 이용하여 각각의 수치를 비교하였다. $^{99m}Tc$의 resolution test에서 NC, AC, SC, ACSC를 각각 적용했 을 때 FWHM (mm)값은 각각 $4.97{\pm}0.46$, $4.73{\pm}0.27$, $49.7{\pm}0.39$, $4.60{\pm}0.26$, $^{201}Tl$에서는 $5.26{\pm}0.28$, $5.14{\pm}0.21$, $5.25{\pm}0.25$, $5.05{\pm}0.23$, $^{131}I$에서는 $6.24{\pm}0.73$, $5.84{\pm}0.57$, $6.24{\pm}0.69$, $5.98{\pm}0.52$의 값을 얻을 수 있었다. 각 방사성 동위원소의 결과 값에서 NC와 비교하여 AC, ACSC를 적용했을 때 통계적으로 유의한 차이를 보였고(P<0.05), SC만을 적용했을 때는 유의한 차이가 없음을 보여주었다(P>0.05). Contrast test에서는 percent contrast(%) 를 4개의 원통에 대한 값을 구했고, NC와 비교했을 때 AC, SC, ACSC의 percent difference (%)가 $^{99m}Tc$은 24.73, 38.10, 67.31, $^{201}Tl$은 30.90, 51.82, 86.02, $^{131}I$에서는 18.60, 46.26, 73.67의 차이를 보였다. 본 연구의 결과에 따르면 $^{99m}Tc$, $^{201}Tl$ 과 같은 낮은 에너지를 가진 핵종에 대해서는 ACSC를 동시에 적용한 영상에서 resolution 향상이 가장 크게 나타났지만, $^{131}I$ 같은 높은 에너지의 핵종에서는 AC만 적용되었을 때 ACSC를 적용했을 때보다 영상의 질이 더 향상됨을 알 수 있었다. 그러므로 SPECT/CT 검사 시 사용되는 핵종의 에너지에 따라 적절한 영상보정기법을 적용한다면 정확한 진단을 위한 최적의 영상을 얻을 수 있을 것으로 사료된다.