There is a lot of heterogeneity, I think - wide differences from one institution to another. In Australia, for example, it is available at only a few centres so this is rarely done, only referred by relatively select clinicians (eg a few geriatricians).

I would not be surprised if there are very few cases in some countries and more in others.

That, then, leads to the question if only a certain few can afford it (obviously in some countries you can only get it if you pay for it) then does that mean a lot of people who need this cannot get it?