Solid phase extraction chromatography-based radiochemical isolation of cyclotron-produced 51Mn from enriched 54Fe targets

Abstract

We report DGA extraction chromatography isolation of ⁵¹Mn from isotopically enriched ⁵⁴Fe. The method has been studied in semi-automated and automated realizations. The former achieves a decay corrected radiochemical yield of 78 ± 1 % (n = 3) and a separation factor of (1.0 ± 0.8) x 10⁵ (n = 3). With GE HealthCare's Solid Target Platform (STP) and FASTlab the latter, fully automated method achieves a decay corrected radiochemical yield of 87 ± 1 % (n = 3) and a separation factor of (2.7 ± 0.9) x 10⁴ (n = 3). Both setups efficiently isolate cyclotron-produced ⁵¹MnCl₂ suitable for human administration as determined by developed Chemistry, Manufacturing, and Controls (CMC) acceptance criteria, and support exploration of ⁵¹Mn as a clinical diagnostic tool.

Keywords: Manganese-51; Radionuclide production; Solid phase extraction chromatography.

Figure 1:

Diagram showing how theoretical thin targets can make up one thick target and how energy is lost as the incident proton beam interacts with each theoretical thin target of thickness x

Figure 2:

(A)Masking of irradiated foil with metal washer of 15 mm inner diameter and (B) resulting autoradiograph with drawn ROIs

Figure 3:

UW-Madison 16 MeV PETtrace cyclotron beam spread as a function of target diameter

Figure 4:

Flow diagram of ⁵¹Mn purification from ⁵⁴Fe using normal DGA resin

Figure 5:

Affinity constants for Mn and Fe in varying concentrations of HCl for both normal and branched DGA (bDGA) resin

Figure 6:

Experimental and theoretical production yields as a function of target mass

Figure 7:

Elution profile and numerical steps for the separation of ⁵¹Mn from ⁵⁴Fe and recovery of ⁵⁴Fe from normal DGA resin.

Figure 8:

Both standard and ⁵¹Mn sample solution HPIC UV chromatogram at 530 nm wavelength (top) with associated logged radioactivity chromatogram of the ⁵¹Mn sample solution (bottom)

Figure 9:

HPGe spectra of the final solution containing ⁵¹Mn

Figure 10:

Example half-life determination from decay data from a fully automated separation, collected over 3 h from end of radiochemical separation