Cross-section measurements for the formation of manganese-52 and its isolation with a non-hazardous eluent

Abstract

Nuclear reaction / Cross section / Thick target yield / Integral yield / Separation of positron emitter52 Mn / Ion exchange chromatography Summary. With respect to the production of no-carrieradded 52 Mn nuclear reactions on natural chromium were investigated. Cross sections of the reactions nat Cr( p, x) 48 V, 48,49,51 Cr, 52g,m Mn were determined in the proton energy range of 7.6 to 45 MeV. Additionally, production yields of 52g,m Mn and 51 Cr were measured in the energy range from 8.2 to 16.9 MeV and therefrom the calculated saturation thick target yields were obtained as (2.55 ± 0.31), (6.96 ± 0.57), and (1.53 ± 0.15) GBq/μA, respectively.For in vivo applications like PET, low toxicity is critical and sufficient activity of a radiolabelled compound mandatory. Thus, additional purification steps after separation of radionuclides and target materials have to be avoided. However, no isolation procedure has been reported in the literature so far where radiomanganese is directly obtained in a nonhazardous solution. Therefore a new separation procedure was developed utilizing the cation-exchange resin DOWEX 50W×8 (H + -form). 52g Mn was quantitatively isolated from "bulk" chromium after 3 to 4 h in non-hazardous 0.067 M ammonium citrate solution. Up to 99% of 52g Mn activity was harvested within 10 to 15 mL eluent solution with no measureable 51 Cr impurities.

Imaging neuronal pathways with 52Mn PET: Toxicity evaluation in rats

“…The isotope production and separation methods have been elaborated (Lahiri et al, 2006, Buchholz et al, 2013, Buchholz et al, 2015, Fonslet et al, 2017 and the first preclinical application study has been performed (Lewis et al, 2015). In that work, 52 Mn was proposed as a dual-modality (PET-MRI) tool for long-term tracking of human stem cells transplanted into a rat brain.…”

“…Furthermore, 52 Mn production and separation methods have been recently developed and optimized (Lahiri et al, 2006, Buchholz et al, 2013, Buchholz et al, 2015, Fonslet et al, 2017 and the tracer has been just introduced into the field of preclinical imaging (Topping et al, 2013, Lewis et al, 2015. The biggest advantage of using 52 Mn for tracing neuronal pathways would lie in the possibility to reduce the manganese dose to the pico-molar range which should eliminate the toxic effects and allow multiple administrations.…”

Optimized separation procedure for production of no-carrier-added radiomanganese for positron emission tomography

“…It is worth mentioning that several other separation methods have been published so far [13,23,[26][27][28] and are summarized in Table 2 for comparison. The co-precipitation of Mn(IV) with the non-isotopic carrier Fe(III), followed by solid phase extraction and anion-exchange chromatography, as proposed by Klein et al [13], provided a 99%…”

“…Reported no-carrier-added separation methods for radiomanganese from the target material chromium [13,23,[26][27][28] still need improvement concerning efficacy and handling. Therefore, the focus of this work was on an optimized radiochemical separation to obtain the PET suitable isotope 52g Mn more easily in its bi-valent oxidation state for the labelling of molecular probes like 1 contrast enhancing agents in MRI.…”

“…A comprehensive report on the proton induced production of radiomanganese and the resulting radionuclide yields has recently been published by Buchholz et al [23] …”