• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1863-1870
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• 2023

Molybdenum-99 (⁹⁹Mo) is used for preparing Technetium-99 m (^99mTc), which is the most widely used isotope in nuclear medicine. In this work, a study for ⁹⁹Mo production based on a high-power electron accelerator has been performed as an alternative approach to produce ^99mTc. In this study, Monte Carlo MCNPX2.6 code has been used to examine a novel idea of simultaneous hybrid production of ⁹⁹Mo via both photoneutron and neutron capture reactions using an electron accelerator in heavy water tank. It is expected that this conceptual design including an arrangement of metallic plates of ¹⁰⁰Mo and ⁹⁸Mo produces total activity of 97.5 Ci at the end of 20-h continuous e-beam irradiation (30 MeV, 10 mA).

• 대한핵의학회지
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• 제23권1호
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• pp.63-69
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• 1989

In order to develop technetium-99m-labelled human albumin microsphere (HAM) for lung scintigraphy, various experimemts such as preparation and fractionation of HAM, establishment of optimal labelling conditions, determination of radiochemical purity, stability test and biodistribution of $^{99m}Tc-HAM$ were carried out. HAM was prepared from the suspension of 1ml aqueous human serum albumin (25%) in 130 ml of olive oil at $130\sim135^{\circ}$ with vigorous stirring. The resulting HAM was fractionated with microsieve to get the desired particle size $(15\sim50\mu)$ and autoclaved for sterilizaiton. The HAM particles were treated with stannous chloride and the pH of the suspension was adjusted to $3.0\sim3.5$ with phosphate buffer. After freeze-drying the contents of single reaction vial containing 5 mg of HAM and 0.2 mg of $SnCl_2$ it was reacted with $Na^{99m}TcO_4$. The labelling yield was higher than 99.5% and the stability of $^{99m}Tc-HAM$ was high enough to maintain 99.1% of radiochemical purity up to 24 hours. Lung and liver uptake in mice was found to be 94% and 0.9%, respectively. Excellent rabbit and human lung scans were also obtained.

• 대한방사성의약품학회지
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• 제5권1호
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• pp.3-10
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• 2019

The activities per volume of $^{188}Re$ and $^{99m}Tc$ from their generators are dependent on the specific activity of their mother nuclides $^{188}W$ and $^{99}Mo$ respectively. After a particular lapse of time, the eluted RI activity is exponentially reduced and thus cannot satisfy the needs of clinical application. The purpose of this study is to develop a $^{188}Re$ and $^{99m}Tc$ concentration device with a compact size that can extend the period of use as well as conveniently concentrate the RI. We designed the concentration module by including two-different check valves that do not required any manual on-off operations. In these concentration process, cation exchange resin embedded with Ag and anion exchange resins were used. After completing the concentrating step, the recovering yield was identified to be more than 93% for $^{188}Re$ generators and 88% for $^{99m}Tc$ generators. Moreover, all these procedures were done within 5 min.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2014년도 추계 종합학술대회 논문집
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• pp.431-432
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• 2014

본 연구는 핵의학과에서 사용하는 $^{99m}Tc$에서 방출되는 광자에너지에 대하여 거리에 따른 인체에 대한 선량당량을 평가하였다. 그 결과 주사기 차폐기구 유무에 따라 선량당량이 차이를 보였으며, 심부선량은 차폐를 하지 않은 경우 평균 $216.026{\mu}Gy/h$, 1 mm 텅스텐 차폐를 하였을 경우 평균 $4.240{\mu}Gy/h$, 2 mm 텅스텐의 경우 평균 0.124 uGy/h의 선량을 보였다. 이에 따라 주사기 차폐기구를 필수적으로 사용하여야 하며 종사자 개개인의 피폭 관리에 항상 유념하여야 한다. 또한 본 연구결과를 바탕으로 종사자의 피폭 감소 방안에 대한 연구가 지속적으로 이루어 져야할 것으로 생각된다.

• Journal of Yeungnam Medical Science
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• 제16권1호
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• pp.101-107
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• 1999

휴식 Tl-201/부하 Tc-99m MIBI 심근관류 SPECT를 흉통을 주소로 내원한 24명의 환자를 대상으로 시행하고, 관상동맥조영술에서 관상동액의 내경이 50%이상 협착이 있는 경우를 유의한 것으로 보고 SPECT결과와 관상동맥조영술의 결과를 비교하였다. 관상동맥질환 진단의 민감도와 특이도는 모두 91.7%였고, 협착이 있는 관상동맥 분지수에 따른 민감도는 단일혈관질환이 75%, 다중혈관질환이 100% 였다. 관상동맥분지 각각에 대한 전단의 민감도는 좌전하행동맥 78%, 좌회선동맥 80%, 우관상동맥 86%였다. 이 연구의 절과와 기존의 Tl-201 이나 Tc-99m MIBI를 단독으로 사용한 경우와 비교했을 때 관상동맥질환 진단의 민감도와 특이도는 비슷하거나 오히려 더 좋은 결과를 보였다. 또한 이 방법은 진정한 의미의 휴식기영상을 얻을 수 있고 휴식기와 부하기 영상 사이에 남아있는 방사능으로 인한 오차에서 벗어날 수 있으며, 휴식기 촬영 후 바로 부하기 촬영을 하므로 전체 검사시간이 줄어 환자에게 편리하고 효율이 높은 검사법이라 생각된다.

• Advances in nano research
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• 제10권5호
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• pp.461-470
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• 2021

Infection is one of the major mortality causes throughout the globe. Nuclear medicine plays an important role in diagnosis of deep infections such as osteomyelitis, arthritis infection, heart valve and heart prosthesis infections. Techniques such as labeled leukocytes are sensitive and selective for tracking the inflammations but they are not suitable for differentiating infection from inflammation. Anionic linear-globular dendrimer-G₂ was synthesized then conjugation to gemifloxacin antibiotic. The structures were identified by FT-IR, ¹H-NMR, C-NMR, LC-MS and DLS. The toxicity of gemifloxacin and dendrimer-gemifloxacin complex was compared by MTT test. Dendrimer-G₂-gemifloxacin was labeled by Technetium-99m and its in-vitro stability and radiochemical purity were investigated. In-vivo biodistribution and SPECT imaging were studied in a rabbit model. Identify and verify the structure of the each object was confirmed by FT-IR, ¹H-NMR, C-NMR and LC-MS, also, the size and charge of this compound were 128 nm and -3/68 mv respectively. MTT test showed less toxicity of the dendrimer-G₂-gemifloxacin than free gemifluxacin (P < 0.001). Radiochemical yield was > %98. Human serum stability was 84% up to 24 h. Biodistribution study at 50 min, 24 and 48 h showed that the complex is significantly absorbed by the intestine and accumulation in the lungs and affects them, finally excreted through the kidneys, biodistribution results are consistent with results from full image means of SPECT/CT technique.

• 대한핵의학회지
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• 제27권2호
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• pp.270-276
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• 1993

$Technetium-^{99m}$ labeling method using bifunctional chelating agent cyclic DTPA has been evaluated with human polyclonal nonspecific IgG. IgG was conjugated with cyclic DTPA with various molar ratio. Reduction of $^{99m}Tc$ was done with $Na_2S_2O_4$ with various molar excess. Labeling efficiency and identification of polymer was confirmed with HPLC using TSK4000 SW column. Polymer was purified with 100 cm Sepharose 6LB column. Cultured $1{\times}10^9$ Staphylococcus aureus were injected into rat thigh 24 hours later labeled IgG was injected, and in vivo distribution was observed 4 and 24 hours thereafter. Reduction of $^{99m}Tc$ was optimal with the 10000-50000 times molar excess of $Na_2S_2O_4$. Polymer formation increased with increasing mloar excess of cyclic DTPA to IgG. Three step labeling-labeling DTPA conjugated IgG after reduction of $^{99m}Tc$-made more polymer than two two step labeling-simultaneous mixing DTPA conjugated IgG, $^{99m}Tc$ and $Na_2S_2O_4$. $^{99m}Tc$ blood clearance and lower uptake in the abscess and other organs. IgG conjugated with 200 times molar excess of cyclic DTPA showed slower blood clearance with 200 times molar excess of cyclic DTPA showed slower blood clearance than that of 200 times molar excess of cyclic DTPA showed slower blood clearance than that of 20 times molar excess. In the $^{99m}Tc$ labeling of IgG with cyclic DTPA for the immunoscintigraphy, obtimal labeling condition should be chosen, and effect of the $^{99m}Tc$ labeled IgG polymer should be considered.

• 대한방사성의약품학회지
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• 제4권2호
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• pp.73-79
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• 2018

In our previous study, tricarbonyl $^{99m}Tc$-labeled TSPO-binding ligand, named $^{99m}Tc$-CB256, having positively charge (+1) was investigated but did not show promising results in in vivo environment despite of a nanomolar binding affinity for TSPO. Because the overall positively charge of $^{99m}Tc$-CB256 would likely interrupt its target protein uptake, we herein designed the neutral tricarbonyl-$^{99m}Tc$ labeled TSPO-binding ligand ($^{99m}Tc$-CB257, 1). $^{99m}Tc$-CB257 was prepared by the facile incorporation of the $[^{99m}Tc(CO)_3]^+$ into a N-(hydroxycarbonylmethyl)-2-picoly moiety in CB257. The radiochemical yield of $^{99m}Tc$-CB257 after HPLC purification was $54.1{\pm}2.4%$ (decay corrected, n = 3). The authentic Re-CB257 (2) was synthesized by using $(NEt_4)_2[Re(CO)_3Br_3]$ in 69.0% yield. The binding affinity of 2 for TSPO was measured in leukocyte and showed approximately 280 times higher than that observed for the positively charged (+1) ligand, Re-CB256 ($K_i=0.57{\pm}0.06nM$ versus $159.3{\pm}8.7nM$, respectively). Our results indicated that 1 can be considered potentially as a new SPECT radiotracer for TSPO-rich cancer and provides the foundation for further in vivo evaluation related with abnormal TSPO-overexpression environments.

• 대한방사성의약품학회지
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• 제6권1호
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• pp.3-9
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• 2020

Tetraiodothyroacetic acid (tetrac) is a derivative of thyroid hormone T₄ and causes anti-angiogenesis by blocking T₄ binding to integrin α_vβ₃. In this study, we synthesized [^99mTc]Tc-Cys-Asp-Gly(CDG)-tetrac and evaluated it in vitro as a tumor angiogenesis imaging ligand. The CDG was conjugated to tetrac as a chelator for technetium-99m labeling. The cold vial containing CDG-tetrac, sodium glucoheptonate, and reducing agent was completed under nitrogen-filled atmospheric glove bag. [^99mTc]Tc-CDG-tetrac was synthesized in quantitative yield by heating the cold vial with [^99mTc]TcO₄^- at 100℃ for 30 min. In vitro serum stability of [^99mTc]Tc-CDG-tetrac was measured by incubating the radioligand in 50% fetal bovine serum at 37℃ and analyzing the incubation mixture by radio-TLC, which showed high stability over 6 h (≥ 98%). Cell binding study was carried out by incubating [^99mTc]Tc-CDG-tetrac with human umbilical vein endothelial (HUVE) cells at 37℃ for 6 h. The cell binding of the radioligand increased from 100% at 0.5 h to 293.7% at 6 h in a time-dependent manner. For blocking study, the cells were incubated with the radioligand in the presence of either tetrac (20 μM) or cRGDyK (20 μM) at 37℃ for 4 h. The results demonstrated that the cell binding of the radioligand was inhibited by tetrac (19.1%) or cRGDyK (35.6%), indicating specific binding of the radioligand to integrin α_vβ₃. Thus, this study suggests that [^99mTc]Tc-CDG-tetrac may be a potential radioligand for tumor angiogenesis imaging.

• Childhood Kidney Diseases
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• 제17권2호
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• pp.57-64
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• 2013

목적: 소아에서 24시간 소변 수집의 단점을 대체하기 위해 $^{99m}Tc$-MAG3 신장 스캔을 통한 신기능을 측정하여, 크레아티닌 청소율과 혈청 cystatin C과 크레아티닌에 의한 사구체 여과율 추정식을 비교하여 연관성을 확인하였다. 방법: 2011년 7월부터 2012년 8월까지 101명의 18세 미만의 환자들을 대상으로 의무기록 후향적 조사로 실시하였고 $^{99m}Tc$-MAG3 신장 스캔을 시행하여 사구체 여과율을 측정하였다. 24시간 소변과 혈액을 체취하여 크레아티닌 청소율을 측정하였고 5개의 추정식을 통해 사구체 여과율을 측정하였다. 결과: 크레아티닌 청소율과 $^{99m}Tc$-MAG3 신장 스캔을 이용한 사구체 여과율의 Pearson 상관 계수는 0.389(P<0.001)이었다. $^{99m}Tc$-MAG3 신장 스캔과 Schwartz 식, Counahan-Barratt 식, MDRD 식, Cockcroft-Gault 식, Filler and Lepage 식, Bokencamp 식에 의한 사구체 여과율의 Pearson 상관 계수는 각각 0.265 (P=0.007), 0.128(P=0.044), 0.216 (P=0.030), 0.230 (P=0.021), 0.356 (P<0.001), 0.355 (P<0.001) 로 확인되었다. 사구체 및 비사구체 신질환의 비교에서 $^{99m}Tc$-MAG3 신장 스캔에 의한 사구체 여과율은 모두 유의한 상관성을 가졌고, 신기능의 저하 유무에 상관없이 $^{99m}Tc$-MAG3 신장 스캔에 의한 사구체 여과율은 크레아티닌 청소율과 유의한 연관성을 보였다. 결론: 크레아티닌 청소율과 $^{99m}Tc$-MAG3 신장 스캔에 의한 사구체 여과율 간에는 유의한 상관성이 있으며 $^{99m}Tc$-MAG3 신장 스캔에 의한 사구체 여과율은 신질환의 기원과 신기능의 정상 여부 모두에서 크레아티닌 청소율을 대체할 수 있는 방법임을 확인할 수 있었다. $^{99m}Tc$-MAG3 신장 스캔 이용 시 정확하고 빠른 결과를 얻을 수 있으리라 생각된다.