Freeze-dried microspheres for selective intra-arterial radionuclide therapy: an affordable solution

Selective intra-arterial radionuclide therapy (SIRT) using radiolabelled microspheres is for the delivery of therapeutic radioisotope to liver cancers and thus, sparing healthy liver. Several radiolabelled microspheres are commercially available. The main issue associated with these microspheres is affordability. Re-188 is a generator produced radionuclide, emits high energy therapeutic beta particle and imageable gamma photons for pre- and post-therapy dosimetry.

Tc-99m/Re-188 labelled microspheres have been developed and quality control tests have been performed for suitable clinical use. The clinical studies with Re-188 microspheres for SIRT have been performed. Post-therapy images were acquired for dosimetry.

The microspheres were found to possess spherical morphology of less than 20 µm size. The quality control revealed the suitability of microspheres for intravenous administration. The preliminary studies in thirty patients demonstrated good retention in tumor and high tumor to normal liver ratio. Re-188 microspheres were well tolerated by patients. Same microspheres labelled with either Tc-99m or Re-188 were used for pretherapy dosimetry and Re-188 labeled microspheres for therapy (SIRT) as a single-day procedure.

The freeze-dried microspheres may emerge as highly cost-effective candidates for both pre-therapy dosimetry and SIRT and may benefit a large population with inoperable liver cancer.