Hi Antonio
*** Disclosure: I am the original author for OpenREM. ***
I can't help you with the health of RADIANCE, though it does seem to be four years since it was updated, and the domain name has expired... Maybe Tessa is able to help with an update?
In the mean time, for the second part of your question, you might like to look at OpenREM. It is a slightly different approach than Tessa used for Radiance, but it is an open source radiation dose management system, and the current release has support for creating RDSR objects from legacy Toshiba scanners which can then be imported to OpenREM. As I think RADIANCE did, OpenREM relies on David Clunie's excellent pixelmed software for this, but the OpenREM code further enhances the richness of the RDSR produced by getting additional information from a subset of the image files. OpenREM can be installed on Linux or Windows, and probably on Mac.
Kind regards
Ed