Cenosphere‐Based 177Lu‐Aluminosilicate Microspheres as a Theranostic β‐Emitter for Selective Internal Radiation Therapy of Hepatic Tumors

Abstract

The narrow fraction of the cenospheres of coal fly ash (30−50 μm; glass phase ∼ 90 wt. %) was used for the preparation of β‐emitting 177Lu‐bearing aluminosilicate microspheres. Two methods of chemical modification to encapsulate 177Lu3+ in the cenosphere’s aluminosilicate matrix were used, such as the formation of (i) microporous or (ii) meso/macroporous structure in the cenosphere shell followed by 175+176Lu3+ sorption. Conversion of Lu‐loaded microspheres into poorly soluble forms was performed via the thermal treatment at 900–1200°C and then 176Lu was transformed to 177Lu by neutron activation procedure in a nuclear reactor. The 176Lu‐bearing products were studied by PXRD, SEM, and EDX spectroscopy methods. It was established that the acid treatment of cenospheres resulting in a meso/macroporous structure in the cenosphere shell is the optimal nondestructive method to produce a microsphere precursor for Lu incorporation. The neutron activation of 176Lu‐bearing microspheres resulted in 177Lu‐microspheres that provide the specific radioactivity of 4.5 GBq/100 mg. The Lu leaching rate from 177Lu‐microspheres in a blood simulator determined according to the State Standard (GOST) R 52126‐2003 was about 10−6−10−7 g/cm2⋅day.