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Radiobiokoniugaty znakowane emiterami elektronów Augera w celowanej terapii radionuklidowej

Wawrowicz Kamil, Bilewicz Aleksander

Wiadomości Chemiczne

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2020

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[Z] 74, 11-12

699--733

EN

In contrast to the radiation therapy methods, that use an external ion beam source, the internal radiotherapy is performed by the direct administration of radionuclides conjugated to a targeting vector. Crucial criteria for the use of radiopharmaceuticals at a selective localization and retention in the tumor lesion are biological or biochemical differences between tumor and non-tumor tissue. Auger electron emitters that can target cancer cells are an attractive agents for internal radiation therapy. Besides of a emitters, radionuclides that decay with the emission of very low energy Auger electrons are well suited for the treatment of small tumors, micrometastases or residual tumor after surgical resection of a primary lesion. In contrast to a radiation, however, Auger emitters have low toxicity when decaying outside the cell during blood transport and they are therefore interesting candidates for targeted radionuclide therapy. However, due to nanometers range of Auger electrons the challenge is to target cancer cells specifically and achieve intracellular and intranuclear uptake for maximum DNA damage. So far, no system has been developed to allow for selective delivery of the Auger electron emitter to the cancer cell and next delivering it to cell nucleus, near the DNA strand. An overview of Auger radiation therapy approaches of the past decade shows several research directions and various targeting vehicles. The latter include small molecules, aptamers, hormones, halogenated nucleotides, peptides oligonucleotides and monoclonal antibodies and their fragments. In present article we discuss the basic principles of Auger electron therapy as compared with targeted α and β radionuclide therapy, characteristic of used Auger emitters and briefly the main advantages and disadvantages of the different targeting modalities that are under investigation.

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Makrocykliczne kompleksy radionuklidów w medycynie nuklearnej

Majkowska A., Bilewicz A.

Wiadomości Chemiczne

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2008

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[Z] 62, 7-8

609-633

EN

The use of radiometal-labeled small complexes and biomolecules as diagnostic and therapeutic agents is a relatively new area of medical research. Radiopharmaceuticals are radiolabeled molecules designed to deliver ionizing radiation doses to specific disease sites. Between the targeting biomolecule and a radionuclide a bifunctional ligand is inserted, one end of which is covalently attached to the targeting molecule either directly or through a linker whereas the other strongly coordinates a metallic radionuclide. Selection of a bifunctional ligand is largely determined by the nature and oxidation state of a metal ion. The metal chelate can significantly affect the tumor uptake and biodistribution of radiopharmaceuticals based on small biomolecules. This is because in many cases the metal chelate contributes greatly to the overall size and lipophilicity of the radiopharmaceutical. Therefore, the design and selection of the ligand is very important for the development of a clinically useful therapeutic agent. The requirement for high thermodynamic and kinetic stability of the metal complex is often achieved through the use of macrocyclic ligands with a functionalized arm for covalent bonding to the biomolecule. In this review synthesis of bifunctional macrocyclic ligands and properties of radionuclide macrocyclic complexes used in nuclear medicine are presented. We describe results in two areas: substituted macrocyclic aza ligands for chelation of hard metal cations, and macrocycles containing sulphur for complexation of soft metal cations. Special attention was paid to stability of the complexes as well as to their lipophilicity, which affect biological properties of the formed radiopharmaceuticals. We also include a forecast of the near-term opportunities that are likely to determine practice in the next few years.

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The radiochemistry cyclotron in University of Helsinki

Helariutta K., Hakanen M., Solin O.

Nukleonika

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2003

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Vol. 48,suppl.2

173-174

EN

The 10 MeV proton cyclotron in the Laboratory of Radiochemistry, University of Helsinki is presented. Recent activities as well as the future research and teaching directions around the cyclotron are discussed.