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The History of Nuclear Medicine
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
In the early 1970s, a new radionuclide was introduced, that is, indium-111 (111In), which significantly affected nuclear medicine imaging for many decades. Initially, 111In-chloride was used for the diagnosis of tumours and for bone marrow scintigraphy. Subsequently, different 111In-chelates, 111In-oxine being the most prominent, were introduced for labelling different types of blood cells for imaging of suspected inflammations, which was first described by Thakur in 1977 [35]. During the 1980s, tumour imaging using labelled monoclonal antibodies progressed considerably, and 111In became one of the most important radionuclides.
Radionuclide-based Diagnosis and Therapy of Prostate Cancer
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Sven-Erik Strand, Mohamed Altai, Joanna Strand, David Ulmert
Technetium-99m is the most readily available and commonly used radionuclide in nuclear medicine. This stems from the fact that 99mTc can be produced from decaying 99Mo using a 99Mo/99mTc generator, which is readily available at affordable prices. 99mTc decays by internal conversion to its ground state 99Tc with a half-life of 6.04 h. The 140 keV emitted γ-photon is well suited for imaging using gamma cameras and SPECT. Indium-111 is also a γ-emitting radionuclide with two 172 keV and 245 keV gamma emissions and 2.8 days half-life. This relatively long half-life renders 111In suitable for radiolabelling of different classes of targeting agents, with varying in vivo kinetics for imaging. One major advantage with indium isotopes is that they could easily be incorporated into different biomolecules using different chelating agents (see below). Other less available SPECT radionuclides include 67Ga (Eγ= 93.3 keV (35.7%) and 184.6 keV (19.7%) with 3.3 days half-life and the radiohalogen 123I (Eγ= 159 keV, t1/2= 13.2 h) a decay product of the daughter 123Xe produced after proton bombardment of 124Xe in a (p, 2n) reaction.
Peptide-Based Drug Delivery Systems: Future Challenges, Perspectives, and Opportunities in Nanomedicine
Published in Shaker A. Mousa, Raj Bawa, Gerald F. Audette, The Road from Nanomedicine to Precision Medicine, 2020
Diego Tesauro, Antonella Accardo, Carlo Diaferia, Vittoria Milano, Jean Guillon, Luisa Ronga, Filomena Rossi
Helboketal. [112] synthesized an amphiphilic OCT derivative by cross-linking the S-acetyl-mercaptopropionic acid peptide (SAMA-TOC) with the Mal-DSPE-PEG2000 phospholipid. Next mixed liposomes were obtained by adding to the OCT derivative adequate amounts of palmitoyloleoyl-phosphatidylcholine (POPC), lyso-stearyl-phosphatidylglycerol (Lyso-PG), distearyl phosphatidylcholine–polyethyleneglycol-2000 (DSPE-PEG2000), and dimyristoylphosphoethanolamine-DTPA (DMPE-DTPA) in a molar ratio of 0.1:11:7.5:0.9:2, respectively. These aggregates are usually employed in nuclear medicine applications radiolabeling with indium-111.
PEGYLATION: an important approach for novel drug delivery system
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Deepa Yadav, Hitesh Kumar Dewangan
Polyethylene glycol also plays an important role in the diagnosis of disease; it is used for in vivo detection of disease by using magnetic resonance or radioactivity. For diagnosis, PEG is given in chelated form using compounds that result in better biodistribution and stability. The features of Polyethylene glycol have also been exploited in diagnostics. Due to the PEGylation circulation time of chelates increased that will be cleared more gradually than the unmodified molecules throughout the kidney or liver, therefore allowing more extensive image by magnetic resonance [45]. The biodistribution of radio diagnostics is profoundly changed, in the case of C225 antibody –PEG-radio metal chelators [46], in which Polyethylene glycol act as a linker between targeting and diagnostic moieties. C225 is a monoclonal antibody directed in opposition to the epidermal growth factor receptor, which is conjugated to a heterobifunctional PEG bearing a radio metal chelator (diethylenetriaminepentaacetic acid, DTPA) at 1 terminus. The conjugate DTPA-PEG-C225 retains 66%of required attraction and additionally when labeled with Indium-111 it shows narrower steady-state delivery than the non-PEGylated Indium-111-DTPA-C225, because of reduced nonspecific binding. So, PEGylation is beneficial in the diagnostic field.
Aptamer-based technology for radionuclide targeted imaging and therapy: a promising weapon against cancer
Published in Expert Review of Medical Devices, 2020
Luca Filippi, Oreste Bagni, Clara Nervi
The main purpose of nuclear imaging is represented by the detection and the quantification of metabolic and molecular changes due to different pathological conditions in living subjects. This approach entails the administration of radiolabeled probes and the detection of photons produced in the process of radioactive decay and interaction with neighboring tissues. Different modalities of detection can be applied, depending on the type of radionuclide bound to the probe. In case of a gamma-emitting probe, such as the already cited 99mTc, or indium-111 (111In) and iodine-123 (123I), the appropriate technological approach is represented by gamma-camera also through single-photon emission tomography (SPECT) or hybrid SPECT/CT system [19]. On the contrary, positron emission tomography (PET/CT) approach, which is characterized by superior sensitivity, spatial resolution, and quantification capabilities, is applied when molecular probes are labeled with positron emitting radionuclides, such as fluorine-18 (18 F) and gallium-68 (68 Ga).
Theranostic approaches in nuclear medicine: current status and future prospects
Published in Expert Review of Medical Devices, 2020
Luca Filippi, Agostino Chiaravalloti, Orazio Schillaci, Roberto Cianni, Oreste Bagni
Pentetreotide, a synthetic chelated analog of somatostatin labeled with the radionuclide indium-111 (111In), was introduced in clinical practice for the imaging of NET, since it presents high affinity for SSTRs 2 and lower affinity to SSTRs 3 and SSTRs 5, while no significant binding was reported for the other receptor subtype [40]. Scintigraphy with 111In-pentetreotide has represented for many years a very useful approach for the in vivo demonstration of SSTRs in NET. More recently, three radiopharmaceuticals, labeled with the radionuclide gallium-68 (68 Ga) have been developed for PET imaging of NET: 68 Ga-DOTAPhe1-Tyr3-Octreotide (DOTATOC), 68 Ga-DOTA-NaI3-Octreotide DOTANOC, and 68 Ga-DOTA-Tyr3-octreotate (DOTATATE) [41]. PET technology has greater sensitivity and specificity than scintigraphy with 111In-pentetreotide and allows an accurate quantitative calculation and represents a single-day procedure [42].