roadmaps

Alpha particles carry much more energy over a much shorter distance than the beta particles used in Lutathera and Pluvicto, so they can be more powerful against small clusters of cancer cells. The first alpha drug was approved in 2013; a wave of alpha versions of existing beta drugs is now in late-stage testing, and the isotopes are still scarce.

Working out how much radiation a treatment actually delivers to a tumour and to healthy organs, rather than just giving everyone the same fixed amount, could let doctors treat some patients more and some less. The tools to do this patient by patient exist and are used in some specialist centres, but most approved radioligand therapies are still given at one fixed dose to everyone.

The radioactive ingredients that make theranostics work come from a small number of ageing nuclear reactors, generators and accelerators around the world. A shortage anywhere in that chain delays cancer scans and treatments; new non-uranium and accelerator-based production lines are being built to fix that, but they take years and hundreds of millions of dollars.

From a sugar tracer that lights up most cancers to tracers that show a single protein, a stromal cell type, or the immune cells inside a tumour.

Ordinary sugar-based PET scans do not work well in the brain because healthy brain tissue itself uses a lot of sugar. Nuclear medicine had to develop tracers that light up brain tumours specifically, first amino acid tracers for gliomas and then a receptor tracer that also opens the door to a matched radioactive treatment for meningioma.

Prostate-specific membrane antigen was found on prostate cancer cells in 1987. It took until 2020-2022 for scans and treatments that target it to reach approval, but once they did, PSMA PET and Pluvicto changed how metastatic prostate cancer is staged and treated, and the same target is now being tried earlier in the disease and with more powerful alpha particles.

The radiopharmaceutical roadmap runs eighty years from radioactive iodine for thyroid cancer to alpha-emitting drugs for prostate and neuroendocrine cancers, with isotope supply as the limiting factor.

Neuroendocrine tumours were the proving ground for the whole idea of theranostics: find a receptor on the tumour, image it with a low-dose radioactive scan, then treat with a matched higher-dose version of the same molecule. That sequence took thirty years to build and is now being extended with more powerful alpha-particle versions.