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Radiolabeled Nanoparticles for Cancer Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
The most commonly employed radioisotopes for SPECT imaging include technetium (99Tc, t1/2: 6.0 h), indium (111In, t1/2: 2.8 days), and radioiodine (131I, t1/2: 8.0 days) and other radioisotopes as given in Table 3.1. Technetium-99m (99mTc, is an isotope of technetium, short-lived metastable radionuclide) is the most commonly employed radionuclide for nuclear imaging. Owing to the remarkable physical properties of 99mTc including the short half-life (6 h) and gamma photon emission (140 keV), this material is highly beneficial for efficient imaging as well as good for patient’s safety. Additionally, 99mTc holds latent chemical properties, which allow this material to be used in kits of numerous types for labeling for multipurpose diagnostic applications. SPECT is often used for imaging ligands, including antibodies, peptides, hormones, and selectins, which are labeled with 99mTc or with other radioisotopes. These molecules slowly diffuse into tissue and exhibit slow clearance from blood that extends for several hours to even days. Some SPECT isotopes with long half-life, such as thallium-201 (201Tl), tin-117m (117mSn), and iodine-125 (125I), are used for imaging of slow biological processes, including cell division, inflammatory process, and effect of therapeutic radiopharmaceuticals.
Nuclear Medicine Imaging and Therapy
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
David Towey, Lisa Rowley, Debbie Peet
Technetium-99m (99mTc) is the main radionuclide used in Nuclear Medicine. This isotope is low cost, easy to produce, primarily a gamma emitter (generating photons within an appropriate energy range), and has a suitable half-life. The emission energy (140 keV) provides a good compromise between being high enough to escape the body, which limits absorption, but still low enough to be easily detected by scintillation crystals. 99mTc is eluted from a molybdenum-99 (99Mo) generator (Figure 5.3) in the form of pertechnetate. The generator contains an aluminium column, with absorbed 99Mo. An evacuated vial is placed at one end of the generator fed by a saline solution at the other. Saline is forced through the column, reacting with the 99mTc to form sodium pertechnetate, which is then collected in the evacuated vial. This is known as eluting the generator, with the resultant pertechnetate being the eluate.
Images from Radioactivity: Radionuclide Scans, SPECT, and PET
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
Many radionuclides have been identified that both emit an appropriate gamma ray energy and form a chemical compound of interest. Technetium-99m can now be attached to so many useful compounds that it is extremely widely used in nuclear medicine imaging. Gamma camera scans with technetium-99m and other radionuclides are used to image the skeleton, urinary tract, lungs, heart, liver, and thyroid gland, among other applications. For example, the distribution of technetium-99m-labeled red blood cells can be used to trace the flow of blood and indicate the quality of circulation throughout the body. Others radiopharmaceuticals are taken up preferentially by a particular organ or by tumors. For example, a chemical compound called technetium-99m-HIDA normally is concentrated in the gallbladder. Thus, an abnormal absence of radioactive tracer compound could indicate impaired circulation in a region of the body (in the first case) or blockage of the gallbladder (in the second). In scintimammography, a technetium-99m tracer compound can be used to image tumors in breast cancer.
Formulation of chitosan coated nanoliposomes for the oral delivery of colistin sulfate: in vitro characterization, 99mTc-radiolabeling and in vivo biodistribution studies
Published in Drug Development and Industrial Pharmacy, 2021
Mohamed H. Aboumanei, Ashgan. F. Mahmoud, M. A. Motaleb
By incorporating radioisotopes into the drug formulation, it is easy to track the drug pathway in vivo. Radioisotopes are considered as signal sources because they can be incorporated into the drug formulation without any effect on their properties and the radioactivity can be measured easily by a gamma scintillation detector [26]. The selection of the suitable radioisotope for radiolabeling needs careful consideration such as the particulate radiation extent, half-life, radiation energy, cost, and availability [27]. Technetium-99m (99mTc) has been widely used in nuclear imaging in the last decade. The half-life of 99mTc is 6.02 h with an energy of 140 keV which is suitable for diagnostic procedures. In addition, it can be obtained easily once elution of molybdenum-99 (99Mo)/99mTc generator with normal saline [28,29].
The effect of radiolabeled nanostructured lipid carrier systems containing imatinib mesylate on NIH-3T3 and CRL-1739 cells
Published in Drug Delivery, 2020
Evren Atlihan Gundogdu, Emine Selin Demir, Meliha Ekinci, Emre Ozgenc, Derya Ilem Ozdemir, Zeynep Senyigit, Makbule Asikoglu
Nanostructured lipid carrier systems (NLCSs) are part of drug delivery systems and comprised of solid and liquid lipids. They have many advantages such as high drug loading capacity (LC), easy to prepare, biocompatible facility, low cost, good stability, long shelf-life, and ease of storage (Khosa et al., 2018). Also, their usage with convenient radionuclides is an attracting major attention in nuclear medicine. Technetium-99m ([99mTc]Tc) is commonly preferred radionuclide for radiolabeling of drug delivery systems since it has ideal properties such as short half-life (6 h), low cost, availability through an inexpensive 99Mo/99mTc generator, varied chemistry, obtains a high activity to be given to the patient without an excessive radiation dose, readily detectable gamma emission (Ucar et al., 2017; Fernandes et al., 2018).
Effect of toxoplasmic infection on the biodistribution of a brain radiopharmaceutical
Published in International Journal of Radiation Biology, 2019
João Cláudio da Costa Urbano, Ranny Beatriz de Carvalho Holanda Leite, Renan Leopoldo Pereira Castro, Clarice Maux Vianna da Silva, Joelma Maria de Araújo Andrade, Cláudio Bruno Silva de Oliveira, Vanessa Santos de Arruda Barbosa, Valter Ferreira de Andrade-Neto, Cecília Maria de Carvalho Xavier Holanda
Mice were randomly divided into 3 groups of 6 animals each: one control group (C), one only infected group (I), and one infected and treated group (IT). The group C received only 0.5 ml of distilled water, by intragastric gavage, for 10 days and in the 10th day received, after anesthesia, 0.1 ml of the radiopharmaceutical 99mTc-ECD via femoral vein. The technetium-99m, of which the radiochemical purity is 95%, was eluted from a generator of molybdenium generator-99 and technetium-99m (99Mo/99mTc) in the form of sodium pertechnetate (Na99mTcO4−), produced by the Institute of Energy and Nuclear Research of São Paulo/Brazil and gently supplied by the Norteriograndense League against Cancer, Natal/RN, Brazil, together with the ECD kit.