TomoTherapy Participates in New Venture to Develop a Compact Proton Therapy System

MADISON, Wis. – April 28, 2008 – TomoTherapy Incorporated (NASDAQ: TOMO) today announced its participation in a new venture, Compact Particle Acceleration Corporation (CPAC), to develop a state-of-the-art, compact proton therapy system for the treatment of cancer. The system will feature a dielectric-wall accelerator (DWA).

CPAC conducted the initial closing of phase I of the investment, and anticipates completing phase I with one or more additional closings over the next several months. Investors in CPAC will include TomoTherapy, private investors and potential customers. A total investment of approximately $45 million is anticipated to be completed in three phases which are linked to key technological milestones.

The DWA technology, which resulted from defense-related research at Lawrence Livermore National Laboratory (LLNL), has the potential to bring fixed and rotational intensity-modulated proton therapy (IMPT) to treat cancer into the medical mainstream.

source; TomoTherapy Inc.