Stellenbosch University (SU) and high-tech company Enlightened Isotopes, a subsidiary of ASP Isotopes, have entered into an R8.5-million research partnership to develop a protocol for the separation of the ytterbium-176 isotope, to be used as a radiopharmaceutical in cancer therapy.

Worldwide, isotope producing companies are looking for alternative technologies as traditional sources, mostly nuclear reactors, are coming to the end of their life cycles.

At present, Russia and China are the world’s largest suppliers of isotopes.

SU Department of Physics laser physicist Dr Christine Steenkamp has been investigating the use of laser-based resonance ionisation as a technique to purify atomic isotopes for medical use since 2015.

She is doing research in the field of resonance ionisation spectroscopy – an extremely sensitive and highly selective analytical measurement method to detect individual atoms and molecules.

Steenkamp and her team have already successfully applied the technique to zinc isotopes, as the production of pure zinc-68 is important for the production of gallium-68 (used in medical positron emission tomography, better known as PET, diagnostic scans). 

She says the project will consist of two phases.

“During the first phase we will use our existing equipment and experimental setup to study and understand this specific isotope of ytterbium.

“This will give us a better understanding of the experimental setup required to control and separate the isotope on commercial scale from the material in which it occurs naturally.”

Ytterbium is a rare earth chemical element that occurs naturally in ores.

One of its seven isotopes, ytterbium-176 can easily be transmuted into radioactive lutetium-177, used primarily in the treatment of prostate cancer.

In nuclear medicine, isotopes that release low levels of radiation are used to target cancer cells.

As body tissues affected by cancer have increased cell activity, the cancer cells will absorb more of the radioactive isotope. In this way, the cancer cells are targeted.

Therapeutic isotopes are, however, expensive and can cost tens of thousands of dollars per gram.  And, as these isotopes remain radioactive for only a short period of time, they need to be produced close to hospitals.

Professor Pieter Neethling, director of the Stellenbosch Photonics Institute at SU, and co-investigator on the project, says high levels of expertise and specialised equipment are a prerequisite to the development of such a protocol.

“We are extremely excited to be able to contribute to the development of such a high-tech isotope enrichment facility in South Africa.”

Enlightened Isotopes and ASP Isotopes project manager Josua Oosthuizen says they are looking forward to working with a worldclass team at SU.

“Although the work is currently focused on ytterbium-176, we have a long pipeline of medical isotopes that in future will be developed in partnership with the SU team.”