XiO Radiation Treatment Planning System, XiO versions equal to or greater than 2.4.0 and less than 4.63.0 The XiO RTP System is used to create treatment plans for any cancer patient for whom external beam radiation therapy or brachytherapy has been prescribed.

The XiO Software currently prompts for entry of CT to ED data for a studyset. No indication is given that the Electron Density data should only be used for Photon and Electron calculations and either Relative Stopping Power or Mass Density should be used for Proton calculations (depending on the algorithm).

The firm, Eletka, Inc., issued an "Important Safety Notice" dated May 18, 2011 via mail to all affected sites. The notice explains the issue and identifies a work around to the problem until the new release is available. The customers were instructed to complete and return the enclosed "Confirmation of Receipt" form via FAX to 314-993-1175, attn: QA; e-mail or mail: CMS Software, Attn: QA, 13723 Riverport Drive, Suite 100, Maryland Heights, MO 63043. The notice states that "this problem has existed since XiO Release 2.4.0 and has been resolved in XiO Release 4.63.0 by adding warning messages and explanations to the XiO On-Line Help. Your site will be notified when this release is available." If you have any question, call 314-993-0003, 800-878-4267 or 408-830-8023.