The use of poly(acrylamide-acrylic acid)-montmorillonite composite for preparing low-activity 60Co, 65Zn, 134,137Cs mixed sealed source for radiometric calibration purposes

Abstract

Poly(acrylamide-acrylic acid)-montmorillonite composite [P(AAm-MA)-M] was synthesized and used for preparing 60 Co, 65 Zn, 134,137 Cs mixed sealed source. The synthesis procedure was based on γ-induced polymerization of polyacrylamide (PAAm) in the presence of acrylic acid (AA), clay minerals (montmorillonite, M), and N,N'-methylenebisacrylamide (NMBA) as a cross-linker. The adsorbent functionality was assayed using FTIR spectroscopy and thermal analysis. The distribution coefficients of 60 Co(II), 65 Zn(II), and 134,137 Cs(I) ions on P(AAm-MA)-M were determined in relation to HCl concentration. P(AAm-MA)-M was loaded with 60 Co, 65 Zn, and 134,137 Cs by equilibrating it (0.5 g) with a mixed solution of 60 Co, 65 Zn, and 134,137 Cs at pH 3 (HCl) for 24 h at 25 ± 1°C. Mixed sealed source containing 5.3, 0.03, 0.05, and 1.05 μCi of 60 Co, 65 Zn, 134 Cs, and 137 Cs, respectively, was prepared by packing 100 mg of the loaded matrix in the cylindrical cavity of a Chinese Artelone capsule. The sealed source was subjected to quality control tests.

ESR statement on the stepwise development of imaging biomarkers

“…Qualification, defined as a “graded, fit-for-purpose evidentiary process linking a biomarker with biological processes and clinical end-points”, is a validation process in large cohorts of patients involving multiple centres, similar to phase III clinical trials, to obtain regulatory approval as surrogate endpoints [4]. A more extensive path to biomarker development has been reported [5]. The first step is the proof of concept, which defines any specific change relevant to the disease that can be studied using the available imaging and computational techniques.…”