Online OsiriX Documentation/Building OsiriX
Now that you have the source code you are ready to build.
1) Open osiriX.xcodeproj
2) Choose '"Unzip Binaries" as the active target and then click Build.
3) Choose "Development" as the active target and then click Build.
You should now have an application that runs. Before you run though if you already have a version of OsiriX installed on your system, BACKUP your OsiriX user data folder since this app will use the same version and there could be conflicts.