July 13, 2011 – Somatom Definition AS Open – a high-end computed tomography (CT) system that can efficiently cover the needs of both diagnostic radiology and radiation therapy – has been cleared by the U.S. Food and Drug Administration (FDA). Delivering good image quality at low dose, the Definition AS Open enables exact contouring for planning while minimizing exposure to the patient. The scanner, manufactured by Siemens Healthcare, has several service offerings and is upgradeable for multipurpose use.
An invaluable tool for contouring, virtual simulation, planning and treatment, the Somatom Definition AS Open has several new radiation therapy (RT) options and modifications that distinguish it as a fully dedicated radiation therapy planning (RTP) system. With its full on-site upgradability from 20 to 64 slices, it can grow with user demands and be fully customized to user requirements.
It supports a balance of image quality and dose with a bore diameter of up to 80 cm, creating a CT that is open to every patient. In addition to the regular field of view (FoV) of 50 cm and the extended FoV of 80 cm, it has a High-Definition (HD) FoV of 65 cm that is optimal for treatment planning. The multi-purpose treatment table with a bariatric top ensures high reproducibility of patient positioning up to 676 pounds, with a deflection of less than 2 mm. The new ReferenceFix function aligns the relation between the different coordinate systems of the CT system and the linear accelerator.
Additionally, an accurate rendering of a moving tumor is achieved with an open interface, compatible with all respiratory gating hardware vendors. The Somatom Definition AS Open has a compact footprint of 200 square feet and offers Complete Dose Protection, a comprehensive portfolio of dose-saving features that enables users to actively manage the dose in every CT examination.
For more information: www.siemens.com/healthcare
December 03, 2025 
