• 대한방사성의약품학회지
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• 제2권1호
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• pp.22-36
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• 2016

$^{68}Ga$ is a promising radionuclide for positron emission tomography (PET). It is a generator-produced ($^{68}Ge/^{68}Ga$-generator) radionuclide with a half-life of 68 min. The employment of $^{68}Ga$ for basic research and clinical applications is growing exponentially. Bifunctional chelators (BFCs) that can be efficiently radiolabeled with $^{68}Ga$ to yield complexes with good in vivo stability are needed. Given the practical advantages of $^{68}Ga$ in PET applications, gallium complexes are gaining increasing attention in biomedical imaging. However, new $^{68}Ga$-labeled radiopharmaceuticals that can replace $^{18}F$-labeled agents like [$^{18}F$]fluorodeoxyglucose (FDG) are needed. The majority of $^{68}Ga$-labeled derivatives currently in use consist of peptide agents, but the development of other agents, such as amino acid or nitroimidazole derivatives and glycosylated human serum albumin, is being actively pursued in many laboratories. Thus, the availability of new $^{68}Ga$-labeled radiopharmaceuticals with high impact is expected in the near future. Here, we present an overview of the different new classes of chelators for application in molecular imaging using $^{68}Ga$ PET.

• 동위원소회보
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• 제21권3호
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• pp.46-60
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• 2006

In recent years the progress of nuclear medicine advanced dramatically in imaging and targeted radionuclide therapy is able to open op exciting perspectives as standard diagnostic and therapeutic modalities, complementing conventional modalities. Positron emission tomography/computed tomography (PET/CT) technology with FDG has been developed clinically in less than 10 years as a routine standard in oncological imaging, including a number of other fluorinated radiopharmaceuticals being evaluated for their ability to complement FDG. However, the limitation of FDG-PET such as non-specific uptake and its short half-life is not compatible with the time necessary for optimal tumour targeting. Therefore, a development of innovative positron-emitting radionuclides with half-lives longer than 10 h is needed. For therapeutic applications, the injection of higher activities is required to reach efficient adsorbed doses in radioresistant solid tumours, while limiting the irradiation of vital organs. In this application, the longer half-life of radiolsotopes are more fit well for radionuclide therapy. To achieve this, researches have to be carried in a largor spectrum of radionuclides for diagnosis and therapy. In the context of rapidly growing nuclear medicine and strong demanding innovative radionuclides, a high-energy (100 MeV), high-intensity (-mA) accelerator with proton (PEFF at KAFRI). will be operating in 2011. The priorities of PEFP will include supporting the nuclear medicine research community by providing those radionuclides with current limited availability by means of a high-energy, high-intensity accelerator.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1265-1268
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• 2023

One important issue in using radiopharmaceuticals as therapeutic and imaging agents is predicting different organ absorbed dose following their injection. The present study aims at extrapolating dosimetry estimates to a female phantom from the animal data of ⁸⁹Zr radionuclide accumulation using the Sparks-Idogan relationship. The absorbed dose of ⁸⁹Zr radionuclide in different organs of the human body was calculated based on its distribution data in mice using both MIRD method and the MCNP simulation code. In this study, breasts, liver, heart wall, stomach, kidneys, lungs and spleen were considered as source and target organs. The highest and the lowest absorbed doses were respectively delivered to the liver (4.00E-02 and 3.43E-02 mGy/MBq) and the stomach (1.83E-03 and 1.66E-03 mGy/MBq). Moreover, there was a good agreement between the results obtained from both MIRD and MCNP methods. Therefore, according to the dosimetry results, [⁸⁹Zr] DFO-CR011-PET/CT seems to be a suitable for diagnostic imaging of the breast anomalies for CDX-011 targeting gpNMB in patients with TNBC in the future.

• Nuclear Medicine and Molecular Imaging
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• 제40권4호
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• pp.200-204
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• 2006

목적: 산소포화도법과 비교하여 동위원소법을 이용한 Qp/Qs측정의 정확도를 알아보고, 이와 연관된 요인이 무엇인지, 추적 검사시 두 검사법의 결과를 서로 비교해서 사용할 수 있는지에 대하여 알아보고자 하였다. 대상 및 방법: 두 검사법으로 Qp/Qs를 측정한 207명의 환자를 대상으로 하였다. 동위원소를 이용한 방법은 폐에 관심영역을 설정하여 시간-방사능 곡선을 얻어서 gamma variate model에 적용하여 면적으로부터 Qp/Qs를 구하였다. 환자의 연령, 좌우 단락의 종류와 동반된 질환 등에 따라서 방사성 동위원소 조영술과 심도자술로 얻어진 Qp/Qs의 상관계수와 일치도를 분석하였다. 결과: 동위원소 검사법과 심도자술로 얻어진 Qp/Qs의 평균치는 각각 $1.85{\pm}0.50,\;1.74{\pm}0.51$이며, 두 검사법으로 얻은 Qp/Qs의 상관계수는 0.86 (p<0.001)으로 강한 상관관계를 보였다. Bland-Altman 분석에서 두 검사법에 의한 Qp/Qs의 일치의 한계값은 $-0.42{\sim}0.63$, 범위는 1.05였다. 심실중격 결손증 환자에서는 상관계수가 0.90으로 강한 상관관계를 보였으며, 일치의 한계값은 $-0.29{\sim}0.45$ 였다. 심방중격 결손증, 심실중격 결손증, 동맥관 개존증 환자와 삼첨판 부전증과 승모판 부전증이 동반된 환자에서의 상관계수는 각각 0.78, 0.90, 0.84, 0.63, 0.44 였으며, 일치의 범위는 1.52, 0.74, 0.96, 1.57. 1.50이였다. 결론: 동위원소 검사법과 심도자술로 얻어진 Qp/Qs는 전체적으로 좋은 상관관계를 보이나 일치의 한계값이 크므로 추적 검사시 서로 호환하여 사용하기 어렵다. 방실판막 부전증이 동반된 경우에는 낮은 상관관계와 낮은 일치도를 보였다.

• 대한핵의학회지
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• 제33권1호
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• pp.11-27
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• 1999

Peptide imaging is a new diagnostic modality in nuclear medicine. $^{111}In$-pentetreotide ($Octreoscan^R$) is the first commercially available peptide radiopharmaceutical. This review article presents the results of previous studies using $^{111}In$-pentetreotide for several disease states, including neuroendocrine tumors, breast cancer and malignant lymphoma. The use of hand-held probe during surgery and the preliminary results of radiotherapy using radiolabeled somatostatin analogues are also reviewed. It can be concluded that somatostatin receptor scintigraphy is a promising diagnostic tool for localizing primary tumors that express receptors for somatostatin, staging secondary spread of tumor tissue, following up after therapy and identifying patients who may benefit from therapy with unlabelled or radiolabeled octreotide. The somatostatin receptor imaging will stimulate the development of new radiopharmaceuticals for other receptors and enhance the therapeutic use of radiolabeled peptides.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2594-2600
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• 2020

A gamma camera system using radionuclide has a functional imaging technique and is frequently used in the field of nuclear medicine. In the gamma camera, it is extremely important to improve the image quality to ensure accurate detection of diseases. In this study, we designed a blind-deconvolution framework after a noise-reduction algorithm based on a non-local mean, which has been shown to outperform conventional methodologies with regard to the gamma camera system. For this purpose, we performed a simulation using the Monte Carlo method and conducted an experiment. The image performance was evaluated by visual assessment and according to the intensity profile, and a quantitative evaluation using a normalized noise-power spectrum was performed on the acquired image and the blind-deconvolution image after noise reduction. The result indicates an improvement in image performance for gamma camera images when our proposed algorithm is used.

• 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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• 제32권6호
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• pp.482-489
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• 1998

목적: 방사성 동위원소 뇌조조영술은 자발성 두 개 내 저압환자의 체위성 두통과 저뇌척수압의 병태생리를 이해하는데 도움을 줄 수 있다. 저자들은 이 질환의 방사성 동위원소 뇌조조영술의 특징적인 소견을 알아보고자 하였다. 대상 및 방법: 자발성 두개내 저압으로 진단되어 방사성 동위원소 뇌조조영술을 시행한 15명을 대상으로 하였다. 뇌조조영술은 Tc-99m DTPA 111-222 MBq를 요추천자를 통해 지주막하강에 투여한 후 감마카메라로 30분부터 2시간 이내에 방광을 포함한 요추부와 경흉추부의 전면상과 측면상을 얻었고, 4, 6, 24시간에 두부와 경흉추부의 전면상과 측면상을 얻었다. 방광 내 방사성 추적자의 조기 배설유무, 척수강 내 방사성의 이동속도, 연조직 섭취정도, 그리고 대뇌궁융부로의 이동 지연 등을 분석하였다. 결과: 방사성 동위원소 뇌조조영술 소견은 대뇌궁융부로의 방사성 추적자의 이동지연(14/15), 연조직의 섭취증가(11/15), 방광 내 방사성 추적자의 조기 출현(13/13) 등이 있었고 뇌척수액의 누출을 시사하는 척수경막강 주위의 방사성 추적자의 국소 집적도 4예에서 있었다. 결론: 방사성 추적자의 이동 지연과 연조직의 섭취증가 및 방광 내 방사성 추적자의 조기 출현 등이 특징적으로 관찰되었고, 이러한 뇌조조영술 소견은 자발성 두개 내 저압의 주된 병태생리가 뇌척수액의 누출임을 시사하는 것으로 판단되었으며, 방사성 추적자 이동의 역동적 측면을 잘 평가하기 위해서는 방광과 연조직을 포함한 30분 영상과 다발적인 연속영상을 획득하는 것이 필요하다고 생각된다.

• 대한핵의학회:학술대회논문집
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• 대한핵의학회 1988년도 제27차 춘계학술대회
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• pp.127.1-127.1
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• 1988

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.399-404
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• 2006

Noninvasive molecular targeting in living subjects is highly demanded for better understanding of such diverse topics as the efficient delivery of drugs, genes, or radionuclides for the diagnosis or treatment of diseases. Progress in molecular biology, genetic engineering and polymer chemistry provides various tools to target molecules and cells in vivo. We used chitosan as a polymer, and $^{99m}Tc$ as a radionuclide. We developed $^{99m}Tc-galactosylated$ chitosan to target asialoglycoprotein receptors for nuclear imaging. We also developed $^{99m}Tc-HYNIC-chitosan-transferrin$ to target inflammatory cells, which was more effective than $^{67}Ga-citrate$ for imaging inflammatory lesions. For an effective delivery of molecules, a longer circulation time is needed. We found that around 10% PEGylation was most effective to prolong the circulation time of liposomes for nuclear imaging of $^{99m}Tc-HMPAO-labeled$ liposomes in rats. Using various characteristics of molecules, we can deliver drugs into targets more effectively. We found that $^{99m}Tc-labeled$ biodegradable pullulan-derivatives are retained in tumor tissue in response to extracellular ion-strength. For the trafficking of various cells or bacteria in an intact animal, we used optical imaging techniques or radiolabeled cells. We monitored tumor-targeting bacteria by bioluminescent imaging techniques, dentritic cells by radiolabeling and neuronal stem cells by sodium-iodide symporter reporter gene imaging. In summary, we introduced recent achievements of molecular nuclear imaging technologies in targeting receptors for hepatocyte or inflammatory cells and in trafficking bacterial, immune and stem cells using molecular nuclear imaging techniques.