TomoTherapy Incorporated Announces Pricing of IPO MADISON, Wis. -- TomoTherapy Incorporated announced today the pricing of its initial public offering of 11,743,420 shares of common stock at a price per share of $19.00, of which 10,602,960 shares are being sold by TomoTherapy Inc. and 1,140,460 shares are being sold by certain selling stockholders. TomoTherapy Inc. expects to receive net proceeds from the offering of approximately $185 million. The shares will be listed on the Nasdaq National Market and will trade under the symbol â€œTTPYâ€ beginning May 9, 2007. The closing of the offering is scheduled to take place on May 14, 2007. The selling stockholders have granted the underwriters a 30-day option to purchase up to an additional 1,761,513 shares of common stock at the initial public offering price to cover over-allotments, if any. Merrill Lynch & Co. acted as sole-bookrunning manager, Piper Jaffray & Co. acted as co-lead manager, and Thomas Weisel Partners LLC, Robert W. Baird & Co. Incorporated and William Blair & Company acted as co-managers for the offering. The offering will be made only by means of a prospectus. A copy of the final prospectus related to the offering may be obtained from: Merrill Lynch & Co., 4 World Financial Center, New York, NY 10080. A registration statement relating to these securities has been filed with, and declared effective by, the U.S. Securities and Exchange Commission. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction. About TomoTherapy Incorporated TomoTherapy Incorporated has developed, manufactures and sells the Hi ArtÂ® system, an advanced and versatile radiation therapy system for the treatment of a wide variety of cancers. Hi ArtÂ® and the TomoTherapy logo are registered trademarks of TomoTherapy Incorporated.