It is a shame that Osirix is only available for MacOSX. Those guys can be proud of what they have achieved. There is nothing close on GNU/Linux.
Judging by their site it is not impossible to port it but a lot more work then simply recompiling. I guess the user interface makes up most of the porting work but I have not looked at their code that close.
On the other hand if their was a market they would have ported it already I guess.
The good news however is their two way xml-rpc interface. One can query Osirix from e.g. GNUmed to allow general practioners manage Dicom data (heart cath, ultrasound) in Osirix. On the other hand Osirix can interact with GNUmed to open a patient or automatically adding an entry to the document archive when reading a CD in Osirix.
This can be made to work on a Mac today but we are not going to buy Macs anytime soon :-)