I finished treatment for prostate cancer this summer. Most of my time in the x-ray machine was spent getting the alignment right. They'd take a CT scan, do some image analysis and other computations, then adjust the table some small amount before turning the beam on.

I'm curious how they do the alignment with the histotripsy machine. I would think that they could obviously do an ultrasound scan to get the gross alignment correct. But perhaps there is a CT scan afterwards that lets them make the fine alignment. It probably also helps that the liver is a much larger gland so aiming is less critical?

I'm not sure how they do it exactly. I know just the nature of the machine is that it has a massive array of ultrasound emitters and sensors.