After some searching on various website, I've come to conclusion that Xcelera might be a discontinued application. The HealthCare department on the Philips website, where the Xcelera was developed, doesn't have anything on this software, therefore it's impossible to say what is the compatibility status with Windows 7 x64.
However, the software might be replaced as well which means new products were added to market.
Use the following information to obtain additional info from the developers: http://www.usa.philips.com/healthcare/about/contact
