Intratumoral injection of radioactive Astatine (211At) microspheres for the treatment of tumors

Background: our aims were to prepare microspheres labelled with radioactive astatine as brachytherapy seeds and to confirm the antitumor ability of these microspheres. materials and methods: chitosan-collagen composite microspheres (ccms) were synthesized through an emulsification crosslink reaction and radiolabelled with 211at using the chloramine-t method. radiation stability was assessed in both phosphate-buffered saline and blood serum. the in vivo distribution and therapeutic effects were evaluated in balb/c nude mice with implanted tumours. results: ccms showed ideal morphological characteristics (diameter of 7.5-15 μm) and acceptable radiation stability (73.99% in pbs and 72.56% in serum after 16 hours). the in vivo biodistribution analysis demonstrated that 211at-ccms were highly localized in tumour tissue. the therapeutic efficacy of 211at-ccms when intratumorally injected into a cervical tumour model was assessed. fourteen days after a single-dose treatment with 211at-ccms, significantly retarded tumour volume growth was observed. conclusion: 211at-ccm brachytherapy has the potential to provide an alternative solution for tumour treatment.