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Biomedical Imaging Molecular Imaging
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
Christian J. Konopka, Emily L. Konopka, Lawrence W. Dobrucki
Of the three radioactive decay patterns discussed in this chapter, isomeric transition is characteristic of the most common radionuclide used in nuclear imaging, 99mTc. Isomeric transition happens when the daughter nuclide of one of the above-mentioned decay processes results in an unstable but relatively long-lived state known as a metastable state. During isomeric transition, the daughter nuclide is only different in energy levels from its parent, while atomic number and mass remain unchanged; these two nuclides are isomers of each other. It is the process of the metastable isomer transitioning to the lower energy stable isomer, known as isomeric transition, that results in the emission of a gamma photon useful for SPECT detection.
North America
Published in Thomas E. Carleson, Nathan A. Chipman, Chien M. Wai, Separation Techniques in Nuclear Waste Management, 2017
Linfeng Rao, Gregory R. Choppin
A transmutation scheme has been proposed by LANL to convert 99Tc into stable ruthenium by thermal neutron capture.22 This scheme requires the separation of Tc from the nuclear waste before transmutation, and/or separation of Ru from Tc after transmutation. Among the techniques proposed for use as steps in these separation schemes are solvent extraction of Tc with liquid amine anion exchangers, ion-exchange separation of cationic Ru species,5 volatilization separation of RuO4,26 and magnetic separation of TcO4-from reduced, paramagnetic forms of Ru.27 All these methods are presently being studied in the laboratory.
Radiopharmaceuticals for Diagnostics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Jim Ballinger, Jacek Koziorowski
The primary clinical use of 201Tl is for myocardial perfusion imaging. Though largely replaced by the 99mTc agents sestamibi and tetrofosmin (see section 2.3.5), there is still some use of 201Tl. For example, its half-life makes it convenient to supply for weekend use when 99mTc agents may not be available. Also, it can be used for dual-isotope myocardial perfusion imaging together with a 99mTc agent.
Photoproton Production of 99m Tc and Its Theranostic Counterpart 101Tc via (γ,p) Reaction on Ruthenium
Published in Nuclear Science and Engineering, 2023
A. Tsechanski, D. Fedorchenko, V. Starovoitova
The isotopic composition of natural ruthenium is presented in Table I. The isotope of interest for 99Tc production is the stable ruthenium isotope 100Ru. Currently, there are no experimental nuclear cross-section data on the (γ,p) reaction for 100Ru over energies in the Giant Dipole Resonance (GDR) regime. Thus, for calculations of 99Tc yields, we had to make use of theoretical cross sections predicted from specific nuclear reaction models. In the present work we used the (γ,p) reaction cross sections for the 100Ru isotope from the TENDL-2019 nuclear data library.[5] Cross sections for the (γ,p) and (γ,n) reactions on 100Ru, together with the available experimental data for the (γ,n) reactions on the ruthenium isotopes 98Ru and 104Ru,[6] are shown in Fig. 1.
PHWR Reactivity Device Incremental Macroscopic Cross Sections and Reactivities for a Molybdenum-Producing Bundle and a Standard Bundle
Published in Nuclear Technology, 2022
In diagnostic nuclear medicine, a radiopharmaceutical consisting of a radioactive atom bound to a substrate molecule is administered to a patient to obtain functional information about the patient’s organs and to diagnose various medical conditions. Technetium-99 m (99mTc) is the most commonly used radionuclide in diagnostic nuclear medicine, 99mTc is produced from the radioactive decay of its parent nuclide, molybdenum-99 (99Mo). 99mTc is used in approximately 30 million procedures per year, accounting for 80% of all nuclear medicine diagnostic procedures worldwide.1 Neither 99Mo nor its daughter product, 99mTc, exist naturally. The parent nuclide, 99Mo, is most commonly produced through the fission of uranium-235 (235U) in nuclear reactors with a fission yield of 6.1% (Ref. 2). 99Mo has a half-life of ~4 days, which means that it reaches saturation activity in ~20 days, after which it needs to be harvested.3
Estimation of uncertainty in transmutation rates of LLFPs in a fast reactor transmutation system via an estimation of the cross-section covariances
Published in Journal of Nuclear Science and Technology, 2021
Naoki Yamano, Tsunenori Inakura, Chikako Ishizuka, Satoshi Chiba
The upper panel of Figure 2 compares the neutron capture cross section of 99Tc calculated by T6 and experimental data. In the lower panel of Figure 2, the standard deviation of the capture cross section is compared with experimental data in the 70-energy group structure of JAERI-FAST-Set. The evaluated error of the thermal capture cross section, Δσ/σ = 0.057 in Mughabghab compilation [24], was well reproduced in our calculation, Δσ/σ = 0.056. In the resolved resonance region, the calculated errors of cross section in the 70 energy groups were 1–10%, reasonably reproducing the experimental data. Chou’s data [25] has 5% error and Kobayashi’s data [26] 27-34has error less than 1% except for large peaks where the errors become large. In the smooth part, a large estimated error of 40% is seen, compared with experimental errors. This is attributed to the scatter of experimental data. Chou’s and Kobayashi’s data at 50 keV are 0.455 ± 0.049 barn and 0.791 ± 0.002 barn, respectively. They are discrepant more than 50%. The estimated cross section is 0.628 barn at 50 keV and the large error covers the scatter of the discrepant experimental data.