[1] Say replacing the hydrogens in glucose with tritium

That's part of the problem. Think you can come up with a synthesis of glucose that replaces the nonlabile hydrogens with tritium, is doable on the days scale, repurifiable for human consumption and mass producable on-site at a hospital?

For reference ($900/20Ci): https://www.perkinelmer.com/product/glucose-d-3-3h-hplc-puri...