I believe that cyclotrons are indeed still in use today. Somebody was telling be about these being used in hospitals for proton therapy. The problem with cyclotrons for such an application, I was told, is that they are not very tunable in energy. But they are cheap! I gather the magnetic field is fixed and the ions (or electrons in the original E. Lawrence design) execute a spiral and come out at a particular energy.
Look up "Bragg peak" in some search engine. Ions tend to deposit their energy locally, according to their energy. So, to treat a tumor that is several cm is size, the energy of the ions must be altered. This is the problem. Cyclotrons like one energy. But they are cheap!
3rd generation light sources use synchrotrons or "storage rings". Here the (usually electron) energy is ramped up, the magnets that keep them in the ring are ramped up accordingly. The beams are periodically kicked out into wigglers to make the 3rd generation light (x-rays, their energies increasing with each generation).
The high-energy-physics proton/anti-proton storage rings are similar, but Much larger. LHC must adjust the magnet strength as the protons become more massive/energetic.
