Thomas Flohr PhD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: We present design considerations and performance estimations for a general purpose CT-system with area detector. Methods and Materials: We estimate performance characteristics for fictive multi-slice spiral CT-systems with increasing number of simultaneously acquired sub-mm slices (16 - 32 - 128 - 256) on the one hand and a CT-system with area detector (> 256 slices) and sequential "step and shoot" scanning on the other hand. Based on this comparison, we derive technical requirements for a general purpose CT-system with area detector with regard to gantry rotation time, minimum number of views per rotation, dynamic range of the data acquisition system and maximum tolerable signal lag. We use a prototype CT-system based on a Sensation 16 gantry (Siemens, Forchheim, Germany) with flat-panel area detector (1024x768 detector channels after 2x2 binning) to confirm these specifications by means of studies with phantoms and anatomical specimen. Results: A further increase of multi-slice spiral performance beyond simultaneous acquisition of 16 to 32 slices results in small clinical improvements which require careful consideration of the expected clinical benefits. CT-systems with area detector and sequential "step and shoot" scanning may open new applications in terms of dynamic volume scanning. For a competitive performance, however, the gantry rotation time has to be below 0.5 s, a minimum of 800 - 1000 views per rotation have to be acquired, the dynamic range of the data acquisition system has to be at least 16 bit, and a signal lag of 0.01% after 30 views must not be exceeded. The prototype CT-system with flat panel detector provides excellent spatial resolution (isotropic 0.25 mm) but does not fulfil these requirements, leading to typical image artifacts which are demonstrated. Conclusion: CT-systems with area detector and sequential "step and shoot" scanning may open new applications, but are a technical challenge. General purpose CT scanning is beyond the possibilities of currently available flat panel detectors. (T.G.F., K.S., C.S., S.P., B.S., S.S. are employees of Siemens Medical Solutions.) Questions about this event email: thomas.flohr@siemens.com

Flohr PhD, T, Design Considerations for a CT-system with Area Detector.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3104606.html