Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jul 27;23(8):1872.
doi: 10.3390/molecules23081872.

14 MeV Neutrons for 99Mo/99mTc Production: Experiments, Simulations and Perspectives

Marco Capogni  1   2 , Antonino Pietropaolo  3 , Lina Quintieri  4   5 , Maurizio Angelone  6 , Alessandra Boschi  7 , Mauro Capone  8 , Nadia Cherubini  9 , Pierino De Felice  10   11 , Alessandro Dodaro  12 , Adriano Duatti  13 , Aldo Fazio  14   15 , Stefano Loreti  16 , Petra Martini  17 , Guglielmo Pagano  18 , Micol Pasquali  19 , Mario Pillon  20 , Licia Uccelli  21 , Aldo Pizzuto  3
Affiliations

14 MeV Neutrons for 99Mo/99mTc Production: Experiments, Simulations and Perspectives

Marco Capogni et al. Molecules. .

Abstract

Background: the gamma-emitting radionuclide Technetium-99m (99mTc) is still the workhorse of Single Photon Emission Computed Tomography (SPECT) as it is used worldwide for the diagnosis of a variety of phatological conditions. 99mTc is obtained from 99Mo/99mTc generators as pertechnetate ion, which is the ubiquitous starting material for the preparation of 99mTc radiopharmaceuticals. 99Mo in such generators is currently produced in nuclear fission reactors as a by-product of 235U fission. Here we investigated an alternative route for the production of 99Mo by irradiating a natural metallic molybdenum powder using a 14-MeV accelerator-driven neutron source.

Methods: after irradiation, an efficient isolation and purification of the final 99mTc-pertechnetate was carried out by means of solvent extraction. Monte Carlo simulations allowed reliable predictions of 99Mo production rates for a newly designed 14-MeV neutron source (New Sorgentina Fusion Source).

Results: in traceable metrological conditions, a level of radionuclidic purity consistent with accepted pharmaceutical quality standards, was achieved.

Conclusions: we showed that this source, featuring a nominal neutron emission rate of about 1015 s-1, may potentially supply an appreciable fraction of the current 99Mo global demand. This study highlights that a robust and viable solution, alternative to nuclear fission reactors, can be accomplished to secure the long-term supply of 99Mo.

Keywords: Molibdenum-99; Technetium-99m; neutron generator.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest and declare that have not received funding, contracts or other forms of personal or institutional funding for this research.

Figures

Figure 1
Figure 1
(color online) Decay scheme of 99Mo: The black arrow indicates the transition of 99Mo directly to the 99Tc ground state; blue arrows indicate the transition from 99Mo to 99mTc and from 99Tc ground state to 99Ru. The yellow arrow indicates the transition from 99mTc to 99Tc.
Figure 2
Figure 2
Cross section of the inelastic nuclear reaction 100Mo(n,2n)99Mo.
Figure 3
Figure 3
(Upper panel) Simulated Iso-flux loci at FNG relative to a neutron emission rate Y = 1010 s−1; (lower panel) Neutron spectra from FNG source for a selection of five neutron emission angles. Referring to the upper panel, angles are counted anticlockwise.
Figure 4
Figure 4
Picture of the natural Molybdenum powder contained into the plexiglass vial used during 14 MeV neutron irradiation at FNG.
Figure 5
Figure 5
Picture of the experimental setup prepared for the 14 MeV neutron irradiation of the natural Molybdenum powder.
Figure 6
Figure 6
Spectrum from activated Aluminum foil upon 15 min irradiation by 14 MeV neutrons from FNG, recorded with the HPGe available in the FNG laboratory. In the spectrum, the main gamma/ray lines are due to: 27Al(n,<)24Na reaction channel (E = 1368 keV), From the gamma activity of the 1368 keV line 14 MeV neutron flux and source yield are determined. The peaks originating from the 27Al(n,p)27Mg inelastic reactions are found at E = 170,843 and 1014 keV. Also visible in the spectrum is the annihilation peak at E = 511 keV.
Figure 7
Figure 7
I 3D reproduction of the geometry of the irradiated Moybdenum powder sample as used for the Fluka simulations.
Figure 8
Figure 8
Picture of the automatable solvent extraction module. (a), In this vial occurs the dissolution with H2O2 in H2O of irradiated natural molybdenum powder and the basification with NaOH. (b), Vial for solvent extraction of pertechnetate with MEK from the aqueous alkaline solution. (c,d), Silica and alumina cartridges respectively, used for the purification of the extracted pertechnetate. (e), Vial (placed inside a shielded lead container) used for the elution of sodium pertechnetate [99mTc]NaTcO4 from the alumina column with saline. (f), Vial used for waste.
Figure 9
Figure 9
Schematic view of the double target NSFS. Two deuteron beams are directed onto a tritium-loaded target where fusion reactions take place. The tritium beams continuously implant tritium onto the target to maintain reaction rate.
Figure 10
Figure 10
Plot of the transient equilibrium between 99Mo and 99mTc. From the trend it is clear that the optimal irradiation time is of about 22 h.
Figure 11
Figure 11
100Mo segmented target used to provide a realistic prediction of 99Mo production at NSFS (2 × 10 × 20 cm3): (upper left): gamma density; (upper right): total charged-particle density; (lower left): total energy deposition; (lower left) electromagnetic energy deposition. Data obtained by using MC Fluka code. All the results are per unit primary particle. The estimations have been obtained by Fluka (version 2011.2c.3) code, assuming a uniform and isotropic irradiation of 14 MeV neutrons coming from the NSFS wheel surfaces.
Figure 12
Figure 12
Gamma-ray spectrum recorded by the INMRI-ENEA HPGe detector from the irradiated Mo powder at FNG facility. Red arrows indicate the gamma-rays from the 99Mo decay.
Figure 13
Figure 13
Gamma-ray spectrum recorded by the INMRI-ENEA HPGe detector from the extracted pertechnetate.
Figure 14
Figure 14
(Color online) 99Mo 6-day Ci production for the different facilities listed in Table 8.
See this image and copyright information in PMC

References

    1. Bé M.M., Chisté V., Dulieu C., Browne E., Chechev V., Kuzmenk N., Helmer R., Nichols A., Schönfeld E., Dersch R. Table of Radionuclides, Monographie BIPM-5. Bureau International des Poids et Mesures; Sèvres, France: 2004. Vol. 1-A=1 to 150.
    1. [(accessed on 28 May 2018)]; Available online: http://www.nucleide.org/DDEP_WG/Nuclides/Tc-99m_tables.pdf.
    1. International Atomic Energy Agency . Non-HEU Production Technologies for Molybdenum-99 and Technetium-99m. IAEA; Vienna, Austria: 2013. (IAEA Nuclear Energy Series No. NF-T-5.4). Technical Reports.
    1. [(accessed on 28 May 2018)]; Available online: http://www.nucleide.org/DDEP_WG/Nuclides/Mo-99_tables.pdf.
    1. OECD Nuclear Energy Agency . NEA-OECD, Report on the Supply of Medical Radioisotopes: An Assessment of Long-Term Global Demand for Technesium-99m. OECD; Paris, France: 2011.

MeSH terms

LinkOut - more resources