The Rigel link on this site also looks quite interesting Rigel Technology
although it's likely you've probably read it.
As an aside - a statement taken from this press-release raises a question in my mind:
The Braincells are completely self-contained, strong and durable and do not require line of sight visibility for test data retrieval or transmission. As a result, the RFID tag tag can be applied either internally or externally to a medical device thus making it less susceptible to theft or loss during cleaning.
I wonder where engineering departments stand RE: fitting tags internally, i.e. opening equipment that may be under warranty or whether this is considered as a "modification" and whether there's any research required to validate the technology - to ensure RFID tags cannot induce failures or problems with certain types of equipment when they're in close proximity to active electronics components or sensitive circuitry located within enclosures whether they're being interrogated or not (most enclosures are EMC protected of course).
Can anyone elaborate on the technology, operation or any relevant standards associated with these devices?