Last week, AREVA, the French reactor manufacturer, announced that they plan to build a facility to produce medical-grade lead-212. That caught my eye, because lead-212 is a product of the decay of radioactive materials like thorium and radium. Lead-212 can be attached to cell-specific peptides to target and kill cancer cells selectively.
Today, in a blogger conference call with Jacques Besnainou, the CEO of AREVA in North America, the new facility came up. I asked about the source of the lead-212, and Besnainou said that it is from “other processing operations” in France. I pressed on what those operations were, and Besnainou said that AREVA would explain, but he didn’t give any details.
Dan Yurman posted on AREVA’s R&D interest in lead-212 about a year ago. He gave a chart of the the decay chain leading to lead-212 (Pb-212), which I reproduce here. But where does the U-232 come from? It is produced by using thorium fuel in a reactor or the natural radioactive decay of thorium.
The chart also gives the half-lives of the various radionuclides – the numbers followed by y, d, h, m, and s (years, days, hours, minutes, and seconds). The half-life of lead-212 is 10.6 hours, so the process will involve a fast separation of the lead-212 followed by its incorporation into the cancer-treating reagent. This sort of process has been done for many short-lived isotopes for cancer detection and treatment.
The source of the lead-212 is most likely thorium, perhaps irradiated in a reactor, perhaps natural. It’s not surprising that AREVA would have some from “other processing operations”; thorium is often present in uranium ore.
I look forward to AREVA’s telling us exactly what the source is.