My treatment was done under sedation. Here is a website that may give clearer information. http://www.sirtex.com/content.cfm?sec=usa&MenuID=1110.
The mapping process was the first thing they did. Going in through the femoral artery they go to each tumor and block off the blood leaving the tumor so the radiation can't go to other organs and cause damage. My proceedure was fairly long because I have 13 tumors and some were hard to get to. I think it varies from patient to patient. After they do the blocking they checked (CT scan I think) to make sure they had it done right. The treatment was administered the same way ... going in through the femoral artery. UW treated the halves of the liver with a couple weeks wait in between. My right half was done first and was more painful and I did have some nausea. I had some pain for a couple days after the first side but not after the second. I was kept over night in the hospital after each half of the liver treatment - but not after mapping. I had very mild after effects and began to feel better within a week or so. Symptoms started to go away not long after I had the treatment.