I know after the 2 treatments the team wanted to see if the PRRT treatments were at least stopping the growth. Im not sure why they chose a CT scan over a MRI, but i can ask at my next appointment. I do know that they wanted to compare CT, MRI, and PET scans to the ones i had from the start. Currently i don’t have any bone cancer involvement.. At this time it’s liver and small intestines.. Just a note after my 6 month scan it showed the tumors were still reducing… Hoe this helps..Vinnie