The Lantheus probe uses fluorine-18 (18F) as the radioisotope,...

The Lantheus probe uses fluorine-18 (18F) as the radioisotope, which is attached to a chemical compound. To make the Lantheous probe you need a cyclotron to first make 18F, which are very expensive facilities and require very highly qualified personnel with specific expertise. You then need to carry out a chemical reaction with the 18-F to attach it to the chemical compound. The reaction and the purification process need to be carried out in a relatively short period of time and then the probe needs to be transported to the hospital/patient.

The TLX probe uses Galium-68 as the radioisotope. Galium-68 can be prepared using a Galium-68 generator, which is small enough to sit on a bench in a lab in the hospital, so is much cheaper in terms of infrastructure. TLX produces a 'cold' kit of their probe, and in the hospital their probe is mixed with Galium-68 produced by the generator (the Galium binds to the probe), which is much simpler than doing the fluorine chemistry and purification. The personnel meed to be qualified but not to the same degree as in a cyclotron. The bottom line is that the TLX product is logistically simpler.