• Title/Summary/Keyword: $^{177}Lu$

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In vivo comparison of Lu-177-labeled phosphonate compounds as potential agents for bone pain palliation in rodents

  • Chang, Young Soo;Lee, Yun-Sang;Kim, Young Ju;Jeong, Jae Min
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.1 no.1
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    • pp.53-61
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    • 2015
  • Lutetium-177 ($T_{1/2}=6.71day$) is an adequate radionuclide for therapy, which has both beta emission ($E_{max}=497keV$) for therapeutic effect and gamma emission (113 and 208 keV) for imaging. $^{177}Lu$ labeled ethylenediamine-N,N,N',N'-tetrakis (methylene phosphonic acid) (EDTMP) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminomethylenephosphonate (DOTMP) have been proposed as radiopharmaceuticals for bone pain palliation. In this study, we compared radiochemistry and biodistribution of $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP. EDTMP and DOTMP were synthesized, and 1 mg of each was labeled with $^{177}Lu$ at pH 7~8 with high efficiency (>98%). For comparative biodistribution studies, $^{177}Lu$-EDTMP or $^{177}Lu$-DOTMP were injected into ICR-mice through tail vein, and then biodistribution data were obtained as percentages of injected dose per gram of tissue (% ID/g). Urine excretions of both agents in mice were checked for 7 days. Rat images were also obtained after injection of $^{177}Lu$-EDTMP or $^{177}Lu$-DOTMP. $^{177}Lu$-DOTMP (100% at 1 min) showed faster labeling than $^{177}Lu$-EDTMP (100% at 30 min). Both of them were stable at least for 21 days at room temperature. High bone uptakes were found for both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP: 38.0 and 34.1% ID/g at 3 hr, respectively; and 33.2 and 18.8% ID/g at 7 day, respectively. Rapid excretions to urine were found for both agents ($^{177}Lu$-EDTMP: 56%, $^{177}Lu$-DOTMP: 63% at 1 day). Other organs showed very low uptakes. Rat images of both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP showed high bone uptakes and low soft tissue uptakes. In conclusion, both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP showed high potential as bone pain palliation agents. $^{177}Lu$-EDTMP showed higher bone uptake and slower bone clearance in mice than those of $^{177}Lu$-DOTMP.

Evaluation of Therapeutic Monitoring of Prostate Cancer (PCa) using [18F]Florastamin, Diagnostic Radiopharmaceutical for PCa: Non-clinical Ex vivo Whole-body Autoradiographic Analysis

  • Min Hwan Kim;Kyongkyu Lee;Hee Seup Kil;Soon Jeong Kwon;Yong Jin Lee;Kyo Chul Lee;Dae Yoon Chi
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.9 no.1
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    • pp.17-21
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    • 2023
  • In this study, we evaluated the targeting of prostate cancer (PCa) using [18F]Florastamin in non-clinical study, for the purpose of therapeutic monitoring of [177Lu]Ludotadipep, a therapeutic radiopharmaceutical for PCa, [18F]Florastamin/[177Lu]Ludotadipep was co-administered to a single-individual prostate tumor bearing mouse model, mimicking clinical condition. Considering the difference in half-life of the two isotopes (18F or 177Lu), image scan of whole-body autoradiography was performed at 24 or 48 h after preparation of frozen section, respectively. Then, it was confirmed whether they showed the same targeting efficiency for the area of tumor. A tumor xenograft model was prepared using PSMA-overexpressing PC3-PIP prostate cancer cells. [18F]Florastamin [111 MBq (3 mCi) in 100 µL]/177Lu]Ludotadipep [3.7 MBq (100 µCi) in 100 µL] was co-administered through the tail vein, and 2 hours after administration, the mice were frozen, and after freezing for 24 hours, whole-body cryosection was performed at 24 h after freezing. Image scanning using cryosection was performed after 24 or 48 hours after freezing, respectively. In the scan image after 24 hours, tumor uptake of [18F] Florastamin/[177Lu]Ludotadipep were simultaneously observed specific uptake in the tumor. In the scan image after 48 hours in the same section, signal of 18F was lost by decay of radioisotope, and specific uptake image for [177Lu]Ludotadipep was observed in the tumor. Uptake of [177Lu]Ludotadipep was specific to the same tumor region where [18F]Florastamin/[177Lu]Ludotadipep was uptake. These results suggested that [18F]Florastamin showed the same tumor uptake efficiency to PCa as [177Lu]Ludotadipep, and effective therapeutic monitoring is expected to be enable using [18F]Florastamin during [177Lu]Ludotadipep therapy for PCa.

Distribution and accumulation of 177Lu-labeled thermally cross-linked superparamagnetic iron oxide nanoparticles in the tissues of ICR mice

  • Hue, Jin Joo;Lee, Hu-Jang;Nam, Sang Yoon;Kim, Jong-Soo;Lee, Beom Jun;Yun, Young Won
    • Korean Journal of Veterinary Research
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    • v.55 no.1
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    • pp.57-60
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    • 2015
  • To investigate kinetics of free $^{177}Lu$ and $^{177}Lu$-labeled thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION), suspensions were intravenously injected into the tail vein of mice at a dose of $5{\mu}Ci$/mouse or 15 mg/kg body weight, respectively. Free $^{177}Lu$ radioactivity levels were highest in kidney followed by liver and lung 1 day post-injection. $^{177}Lu$-labeled TCL-SPION radioactivity in liver and spleen was significantly higher compared to that of other organs throughout the experimental period (p < 0.05). Radioactivity in blood, brain, and epididymis rapidly declined until 28 days. Based on these results, TCL-SPION could be a safe carrier of therapeutics.

Preparation and Bioevaluation of 177Lu-labelled Anti-CD44 for Radioimmunotherapy of Colon Cancer

  • Lee, SoYoung;Hong, YoungDon;Jung, SungHee;Choi, SunJu
    • Journal of Radiation Industry
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    • v.9 no.4
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    • pp.187-192
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    • 2015
  • CD44 is a particular adhesion molecule and facilitates both cell-cell and cell-matrix interactions. In particular, splice variants of CD44 are particularly overexpressed in a large number of malignancies and carcinomas. In this study, the $^{177}Lu$-labelled CD44 targeting antibody was prepared and bioevaluated in vitro and in vivo. Anti-CD44 was immunoconjugated with the equivalent molar ratio of cysteine-based DTPA-NCS and radioimmunoconjugated with $^{177}Lu$ at room temperature within 15 minutes. The stability was tested in human serum. An in vitro study was carried out in HT-29 human colon cancer cell lines. For the biodistribution study $^{177}Lu$-labelled anti-CD44 was injected in xenograft mice. Anti-CD44 was immunoconjugated with cysteine-based DTPA-NCS and purified by a centricon filter system having a molecular cut-off of 50 kDa. Radioimmunoconjugation with $^{177}Lu$ was reacted for 15 min at room temperature. The radiolabeling yield was >99%, and it was stable in human serum without any fragmentation or degradation. The radioimmunoconjugate showed a high binding affinity on HT-29 colon cancer cell surfaces. In a biodistribution study, the tumor-to-blood ratio of the radioimmunoconjugate was 43 : 1 at 1 day post injection (p.i) in human colon cancer bearing mice. The anti-CD44 monoclonal antibody for the targeting of colon cancer was effectively radioimmunoconjugated with $^{177}Lu$. The in vitro high immunoactivity of this radioimmunoconjugate was determined by a cell binding assay. In addition, the antibody's tumor targeting ability was demonstrated with very high uptake in tumors. This radioimmunoconjugate is applicable to therapy in human colon cancer with highly expressed CD44.

Novel Bombesin Analogues Conjugated with DOTA-Ala(SO3H)-4 aminobenzoic acid and DOTA-Lys(glucose)-4 aminobenzoic acid: Synthesis, Radiolabeling, and Gastrin Releasing Peptide Receptor Binding Affinity

  • Lim, Jae Cheong;Choi, Sang Mu;Cho, Eun Ha;Kim, Jin Joo
    • Journal of Radiation Industry
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    • v.7 no.2_3
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    • pp.191-200
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    • 2013
  • In this study, a novel bombesin (BBN) analogues, DOTA-Ala($SO_3H$)-4 aminobenzoyl-Gln-Trp-Ala-Val-Gly-His-Leu-Met-$NH_2$ (DOTA-sBBN) and DOTA-Lys(glucose)-4 aminobenzoyl-Gln-Trp-Ala-Val-Gly-His-Leu-Met-$NH_2$ (DOTA-gluBBN), were synthesized and radiolabeled, and their binding affinities were evaluated. Peptides were prepared by a solid phase synthesis method and their purities were over 98%. DOTA is the chelating agent for $^{177}Lu$-labeling, and the DOTA-conjugated peptides were radiolabeled with $^{177}Lu$ by a high radiolabeling yield (>98%). The Log P values of DOTA-sBBN and DOTA-gluBBN were -2.20 and -2.79, respectively. 50.41% of $^{177}Lu$-DOTA-sBBN and 72.97% of $^{177}Lu$-DOTA-gluBBN were left undegraded by the serum incubation at $37^{\circ}C$ for 48 hr. A competitive displacement of $^{125}I-[Tyr^4]$-BBN on the PC-3 human prostate carcinoma cells revealed that 50% inhibitory concentration ($IC_{50}$) were 1.46 nM of DOTA-sBBN and 4.67 nM of DOTA-gluBBN indicating a highly nanomolar binding affinity for GRPR. Therefore, it is concluded that $^{177}Lu$-DOTA-sBBN and $^{177}Lu$-DOTA-gluBBN can be potential candidates as a targeting modality for the Gastrin-releasing peptide receptor (GRPR)-over-expressing tumors, and further studies to evaluate their biological and pharmacological characteristics are needed.

Development of bombesin peptide kit for prostate cancer diagnosis and treatment using 64Cu/177Lu.

  • Kim, Mi Hyun;Kim, Min Hwan;Kim, Kwang Il;Kim, Jung Young;Lee, Tae Sup;Kang, Joo Hyun;Lee, Kyo Chul;Lee, Yong Jin
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.3 no.2
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    • pp.59-64
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    • 2017
  • It has been reported that $^{64}Cu$ was radiolabeled with bombesin (BBN) peptide binding to the gastrin releasing peptide receptor expressed in human prostate cancer cells (PC3), confirming tumor target efficacy in mouse model. In this study, we developed the kit for the diagnosis and treatment of prostate cancer that can be used clinically using bombesin peptide available of $^{64}Cu$ and $^{177}Lu$ radioisotope labeling. The NODAGA-galacto-BBN peptide containing the NODAGA chelator and galactose was dispensed into a sterilized glass vial and lyophilized to prepare a kit. The stability of the kit after long-term storage in the $4^{\circ}C$ cold chamber and the radiolabeling efficiency after $^{64}Cu$ or $^{177}Lu$ labeling were confirmed by thin layer chromatography. When labeling with $^{64}Cu$ at the initial stage of storage, labeling efficiency of NODAGA-galacto-BBN peptide kit was over 96%, labeling efficiency was over 90% when $^{177}Lu$ was labeled. At 11 months after storage, the radiolabeling efficiency of kit against $^{64}Cu$ and $^{177}Lu$ was each over 95% and 90%. The cell viability was significantly reduced in the $^{177}Lu$-NODAGA-galacto-BBN treated group compared with the control and $^{177}Lu$ alone treated group in clonogenic assay. In conclusion, the NODAGA-galacto-BBN kit prepared by the lyophilization showed high stability over time and high yield of radioisotope labeling. Also $^{177}Lu$-NODAGA-galacto-BBN confirmed high cytotoxicity to prostate cancer cells. Therefore, the NODAGA-galacto-bombesin kit is expected to be useful for the diagnosis and treatment of prostate cancer patients.

177Lu-EDTMP radiation absorbed dose evaluation in man based on biodistribution data in Wistar rats

  • Reza Bagheri
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.254-260
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    • 2023
  • Skeletal metastases are common in patients suffering from various primary cancers. Radiopharmaceuticals are an effective option for bone pain palliation. In this work, the radiation absorbed dose of 177Lu-EDTMP radiopharmaceutical was estimated for adult man based on biodistribution data in Wistar rats. The MIRD dose calculation method and the Sparks and Aydogan methodology were applied. The results shows that about 46% of injected activity is cumulated on the surface of the trabecular and cortical bones. Radiation absorbed doses of red bone marrow and osteogenic cells were estimated to about 1.1 and 6.2 mGy/MBq, respectively. The maximum administrated activity was obtained 27 MBq/kg of body weight with an effective dose of 0.23 mSv/MBq. The results were compared with other available data from literature. This study indicated that 177Lu-EDTMP provides therapeutic efficacy for achieving bone pain palliation with low undesired dose to other normal organs.

Antibacterial Activity Evaluation of Radioisotope Lu-177 with a Modified Tube on Plate Core (중심부에 주입구가 존재하는 플레이트를 통한 방사성동위원소의 항균능력 측정)

  • Joh, Eun-Ha
    • Microbiology and Biotechnology Letters
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    • v.41 no.4
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    • pp.469-471
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    • 2013
  • In this study, we measured the anti-bacterial activity of radioisotope Lu-177 using a new laboratory instrument. The disk method used for the measurement of existing anti-bacterial antibiotics is drug diffusion into the medium. To measure the antimicrobial activity of a radioisotope, a new type of laboratory instrument is necessary to prevent the drug from spreading and the present invention was thus tested. In the medium, a space isolated separately for radioisotope injection was used to prevent the radioisotope from spreading and radioisotopes are actually injected by this system. We found that the antibacterial activity increased according to the radiation dose increases. It is expected that, through the present study, measuring the antibacterial activity of the other radioisotopes easily in the laboratory will be possible.

Synthesis, Radiolabeling and Gastrin Releasing Peptide Receptor Binding Affinity of a Novel Bombesin Antagonist-Based Peptide, DOTA-Ala(SO3H)-Aminooctanoyl-Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH2

  • Lim, Jae Cheong;Choi, Sang Mu;Cho, Eun Ha;Kim, Jin Joo
    • Journal of Radiation Industry
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    • v.7 no.2_3
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    • pp.127-134
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    • 2013
  • Bombesin receptors are overexpressed in many kinds of human tumors. In particular, the gastrin releasing peptide receptor (GRPR) which is also called bombesin receptor subtype 2, has been identified in prostate cancer. In the present study, we developed a bombesin antagonist-based $^{177}Lu$-labeled peptide, $^{177}Lu$-DOTA-$Ala(SO_3H)$-Aminooctanoyl-Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-$NH_2$ (DOTA-sBBNA). DOTA-sBBNA was prepared using a solid phase synthesis method. It was labeled with $^{177}Lu$ by a high radiolabeling yield (>98%), and its Log P value was -2.05. The radiolabeled peptide was highly stable in serum incubation at $37^{\circ}C$ for 48 hr. A competitive displacement of $^{125}I-[Tyr^4]$-Bombesin on the PC-3 human prostate carcinoma cells revealed that the $IC_{50}$ value of the peptide was 6.76 nM indicating a highly nanomolar binding affinity for GRPR. These results suggest that $^{177}Lu$-DOTA-sBBNA can be a potential candidate for targeting prostate cancer, and further studies to evaluate its biological characteristics are needed.

Antibody radiolabeling with diagnostic Cu-64 and therapeutic Lu-177 radiometal

  • Abhinav Bhise;Jeongsoo Yoo
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.8 no.1
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    • pp.45-49
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    • 2022
  • With the development of monoclonal antibodies, therapeutic or diagnostic radioisotope has been successfully delivered at tumor sites with high selectivity for antigens. Different approaches have been applied to improve the tumor-to-normal ratio by considering the in vivo stability of radioimmunoconjugates as a prerequisite. Various stable and inert antibody radiolabeling techniques for radioimmunoconjugate preparation have been extensively evaluated to enhance in vivo stability. Antibody radiolabeling techniques should be rapid and easy; they should not disrupt the immunoreactivity and in vivo behavior of antibodies, which are coupled with a bifunctional chelator (BFC) to stably coordinate with a radiometal. For the design of BFCs, radiometal coordination properties must be considered. However, various diagnostic radionuclides, such as 89Zr, 64Cu, 68Ga, 111ln, and 99mTc, or therapeutic radionuclides, such as 177Lu, 67Cu, 90Y, and 225Ac, have been increasingly used for antibody radiolabeling. In addition to useful radionuclides, 64Cu and 177Lu with the most accessible or the highest production rates in many countries should be considered. In this review, we mainly discussed antibody radiolabeling techniques and conditions that involve 64Cu and 177Lu radiometals.