Positron and γ-ray intensities in the decay of ⁴⁵Ti

Abstract

Abstract:To evaluate the PET-imaging properties of the promising positron emitter 45 Ti, its + -and -ray intensities were measured. Use of the cation-exchange resin DOWEX 50W×8 (H + -form) enabled the isolation of radiochemically pure, no-carrier-added 45 Ti from "bulk" scandium after proton bombardment. Thin, no-carrier-added 45 Ti samples were prepared. The combination of -ray and X-ray spectrometry with -coincidence counting allowed for the first time the experimental determination of the positron intensity as (85.67 ± 2.23)% and the absolute intensity of the 720.22 keV -ray as (0.1171 ± 0.0057)%.

Expanding the PET radioisotope universe utilizing solid targets on small medical cyclotrons

“…45 Ti is produced via the 45 Sc(p,n) 45 Ti nuclear reaction. 128 The reaction primarily takes place within the 16 to 8 MeV energy range, with a threshold energy of 2.9 MeV. 128 Regardless, a range restricted to 15 to 8 MeV was recommended to reduce the production of isotopic and non-isotopic impurities during bombardment.…”

Target development for diversified irradiations at a medical cyclotron

“…The results on nuclear data measurements are summarized in Table 2 (cf. Buchholz et al, 2013;Kuhn et al, 2015). For developing radiochemical separation schemes, the materials irradiated included Sc ( Decay data In progress a All irradiations were done with 16.7 MeV protons using the dummy target in position ➀ (cf.…”

Thermochromatographic separation of 45Ti and subsequent radiosynthesis of [45Ti]salan

“…Further studies on their distribution, uptake and mechanism of action rely on imaging techniques such as positron emission tomography (PET), which allows for non-invasive assessment of the biological fate of radiolabeled drugs while they distribute in vivo. The titanium isotope 45 Ti has a half-life of 3.1 h, a high positron branching ratio (β + = 84.8%) and low maximum positron energy (E β+max = 439 keV), negligible secondary gamma emission and a low β end point energy of 1.04 MeV, making it an ideal candidate for use in PET studies [12][13][14]. However, while the radiometal can be produced by transmutation of naturally monoisotopic scandium with low energy protons [15,16], 45 Ti radiochemistry is hampered by the high oxophilicity (θ = 1.0) and hydrolytic instability of Ti 4+ ions in aqueous environments, which necessitate the use of strongly acidic conditions [17,18].…”