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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.
The History of Nuclear Medicine
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
In addition to 30P, the couple produced 13N and 27Si, which all demonstrated a continuous spectrum of positrons. However, the amount of activity produced was insufficient for any application. In the nuclear reaction, in addition to the 30P, a neutron is emitted, which was at first misinterpreted as a gamma photon. After additional experiments, James Chadwick (1891–1974) presented a correct interpretation of these experiments in 1932, and the neutron was discovered. The discovery of the neutron changed the radionuclide research scene, since it enabled artificial radionuclides to be produced without an accelerator.
Partial Body Neutron Activation — Hand
Published in Stanton H. Cohn, Non-Invasive Measurements of Bone Mass and Their Clinical Application, 2020
Thermal neutron bombardment converts 48Ca, one of the stable isotopes of natural calcium, into radioactive 49Ca. Similarly, natural sodium and chlorine are converted into radioactive 24Na and 38C1. All three of these isotopes are gamma photon emitters. On the other hand, 32P, formed under the same irradiation conditions from natural phosphorus, emits only β-particles that are very quickly absorbed by matter. In order to measure phosphorus, it is necessary to use more energetic fast neutrons; these transmute natural phosphorus into a gamma emitting radioisotope, 28A1. Bone tissue is particularly suitable for in vivo neutron activation analysis because of its high mineral content; a weak neutron flux, which delivers a low irradiation dose, is adequate to induce an accurately measurable amount of radioactivity.
Plaque brachytherapy for choroidal melanoma: strategies and techniques to reduce risk and maximize outcomes
Published in Expert Review of Ophthalmology, 2020
Radiotherapy particles have different characteristics and energies that propel them through tissue (Table 1) [5–7]. Compared to beta-electrons, the relatively energetic gamma photon pass through tissue with fewer interactions (absorbed dose) prior to reaching their prescription point.
Isolation of the effects of alpha-related components from total effects of radium at low doses
Published in International Journal of Radiation Biology, 2022
Chandula Fernando, Soo Hyun Byun, Xiaopei Shi, Colin B. Seymour, Carmel E. Mothersill
As the source particles from the 226Ra decay, two source cards, one for conversion electrons and the other for X-ray and gamma photon. The X-ray and gamma photon energies and emission probabilities were retrieved from Table of Radioactive Isotopes.