Summary of TOMOTHERAPY INC

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

Item 1.01 Entry into a Material Definitive Agreement.

On January 13, 2009, TomoTherapy Incorporated (the "Company") entered into a Manufacture and Supply Agreement (the "Supply Agreement") with an effective date of October 8, 2008, with Siemens AG Healthcare Sector, Components & Vacuum Technology, having a business address at Henkestrasse 127, 91052 Erlangen, Germany ("Siemens"), for the manufacture, purchase and sale of linear accelerators and related components. The Supply Agreement supersedes the Manufacture and Supply Agreement dated November 14, 2003, between the Company and Siemens Medical Solutions, USA, Inc., located in Concord, California.

A linear accelerator is a key component in radiation therapy systems, used to create high-energy x-rays for cancer treatment. Siemens serves as the primary source of linear accelerators for the Company at the current time.

Pursuant to the Supply Agreement, the Company receives a discount off of the base price for all parts. Additionally, a volume discount and a time-based cumulative discount are applied on linear accelerator purchases.

The linear accelerators are warranted for eighteen months from the date of delivery or twelve months from the date of installation at a customer site, whichever occurs first. The prior agreement with Siemens provided for a 12-month warranty from the date of delivery. All other products from Siemens under the Supply Agreement carry a 6-month warranty from the date of delivery.

After the initial five year term of the Supply Agreement, it will automatically renew for successive one-year periods thereafter unless either party provides at least eleven months' written notice of termination to the other party. In addition, the Supply Agreement may be terminated: (1) by the Company if a certain percentage of the linear accelerators fails within one-year due to manufacturing and/or material defects, (2) by either party in the event of bankruptcy or suspension of operations, or (3) by either party after providing written notice of a breach and a 30-day opportunity to cure. In the event Siemens terminates the Supply Agreement, the Company may place a last time purchase order no later than 90 days prior to termination to provide expected production needs for one year.

Siemens will repair linear accelerators post-warranty at a price not to exceed a specified maximum, such price to be set forth following the repair and test of ten units. Siemens will reimburse the Company every six months for the Company's costs incurred to ship the products from Frankfurt, Germany upon receiving a written statement of such costs.

The Supply Agreement, as redacted in accordance with a request for confidential treatment, is attached hereto as Exhibit 10.1 and incorporated herein by reference.