Contrary to what this press release implies, radiation treatments are focused too. The basic idea is that you use a rotating beam source with a center of rotation at the exact spot you want to treat. The beam delivers only a fairly modest dose to most of the surrounding issues because of its continual motion, but it always passes through the center, so the cumulative dose in that area is far higher. This image illustrates the idea:

https://patients.uroweb.org/wp-content/uploads/2018/12/Radia...

It's not perfect, and acoustic waves should have fewer side effects, but we already have the ability to selectively target a specific location inside your body.