Xiaochao Xu PhD, Presenter: Nothing to Disclose

Joshua Kim, Abstract Co-Author: Nothing to Disclose

Philip Laganis, Abstract Co-Author: Employee, XinRay Systems LLC

Derek Schulze, Abstract Co-Author: Nothing to Disclose

Yongguang Liang, Abstract Co-Author: Nothing to Disclose

Tiezhi Zhang PhD, Abstract Co-Author: Nothing to Disclose

Cone-beam computed tomography (CBCT) is an important online imaging modality for image-guided radiotherapy and intervention. But its image quality is significantly inferior to diagnostic CT due to excessive scatters and suboptimal detector performance. We are developing a novel Tetrahedron Beam Computed Tomography (TBCT) imaging system which circumvents the inherent problems of CBCT. A TBCT benchtop system has been built with a 75 pixel field emission x-ray. Imaging studies are performed.

The TBCT imaging system consists of a linear x-ray source array and a linear detector array which are aligned perpendicular and parallel to rotation plane respectively. A TBCT bencthtop system has been built with a 75-pixel field emission x-ray tube that is able to produce 3mA cathode current. A 5-row CT detector array was built using silicon photodiodes and CdWO4 scintillators with a maximum sampling rate at 6kHz. The x-ray beams are collimated to fan-shape by a group of multi-slot collimators. System control and data acquisition hardware and software were developed. FDK-based TBCT image reconstruction algorithm was developed. To compensate limited cathode current, a frequency-domain multiplexing scheme is being developed to turn on all the pixels of the linear x-ray source simultaneously but in different frequencies.

Due to its scatter rejection geometry and the use of high-performance discrete x-ray detectors, TBCT image quality is expected to be comparable to that of diagnostic fan beam CT. A fully functional TBCT benchtop has been built. Initial phantom scans produced excellent images without scatter artifacts. Currently we are performing final system tune-up and image quality evaluation.

A TBCT benchtop system has been successfully built. The multiple pixel field emission x-ray tube is fully functioning but a high tube current is desired for future clinical systems. Initial imaging result showed excellent images without significant artifact. Upon finishing the linear x-ray multiplexing scheme, the scanning time will be greatly reduced.

TBCT would significantly improve online image quality. Clinical implementation of TBCT would improve precision of image-guided radiotherapy and intervention treatment.

Xu, X, Kim, J, Laganis, P, Schulze, D, Liang, Y, Zhang, T, Development of a Tetrahedron Beam Computed Tomography Benchtop System with a 75 Pixel Field Emission X-Ray Tube.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008969.html