It's a treatment for metastatic disease usually although it can be used to acheive local control in primary cases where the tumor tends to be resistant to EBRT. ONe can think of it as a targeted systemic radiotherapy modality, although that description can be a bit misleading.
Here is a link to an abstract for one of many American studies:
http://www.redjournal.org/article/S0360-3016(09)00018-2/abstract
In the case of pancreatic neuroendocrine cancer (which Jobs had resected in 2004), short range beta emitters (usually Y-90 or Lu-177) are attached to a hormone (octreotide) which deliveres its payload at the receptor sites. Being quite familiar with the treatment I can tell you if this is a recurrence, that is what he recieved in Basel. Unfortunately, recurrences are not rare in PNT.
The 5-year survival rates for recurrent/metastatic neuroendocrine cancers have more than doubled since 2004, so yes this is indeed news and not desperation as you put it. We can say the same for stem cell treatments in certain instances as well. I won't claim to know exactly what Manning had done or what the exact nature of his injury was, but his trip was quite likely not borne of desperation.
If anyone is interested in more information, technical or not, related to these radiologic or stem cell treatments I'd be happy to oblige.