Radiochemistry

A radioisotope is a non-stable isotope.

Isotopes.

Radiochemistry can't separate isotopes. For example, radiochemistry can't separate ¹⁷⁶Lu and ¹⁷⁷Lu. Isotope separation remained an impossible challenge in the 1900s. Then in the 1940s, Ernest Lawrence invented the calutron in Oak Ridge, TN, which was used to separate uranium-235. It works by ionizing by electron bombardment, separating by mass to charge ratio, and not magnetic moment to mass ratio. It relies on Lorentz force curvature. Separating isotopes by magnetic means became the more efficient method. In the 1980s, came laser isotope separations (AVLIS and MLIS). In the 2000s, this was advanced with optical pumping (laser cooling). In an optical pumping field, atoms went from m = 0 to m = 1 (from not affected, to affected by a magnetic field). In 2005, this was advanced with cooling atoms in a 1-way wall, and in 2008, this was advanced with where atoms in a magnetic field trapped inside a tweezer. This was more efficient than laser ionization.

Then in 2023, came MAGIS (magnetically-activated and guided isotope separation). By the magnetic moment to mass ratio, can get Li-7 to 99.95% and Yb-176 to 99.98%. But MAGIS won't protect from gamma radiation, so use MRLIS (multi-resonant laser isotope separation). For MRLIS, the patent was filed by UT Austin, MGR, on March 25, 2024.

Potentially the hardest isotope to separate is Mo, as it is also hard to vaporize it. You need to put it in a 3000 K oven.

Cost of isotopes (2025).

1 g of Fe-58 costs $350,000.

For medicine, Fe-55 not safe for children, but Fe-57 and Fe-58 are, and they are traceable in blood. But 10 mg costs $35,000.

Cost of actinides (2025).

-5 mg of Cf is around 2 million. It's hard for universities to have more than 5 mg of actinides, but an exception is for Np, which universities can have 10 mg.

Some promising isotopes for cancer therapy.

-Lu-177 is a beta-emitter, with a half life of 1 week. Its range in tissue is 1 mm. It can do gamma emission for imaging.
-Ac-225, having a half-life of 12 days, releases α particles to kill tumor cells.

Working with actinides.