A ray-tracing backprojection algorithm for cone beam CT

Jun Lu; Tinsu Pan

doi:10.1117/12.709442

28 March 2007 A ray-tracing backprojection algorithm for cone beam CT

Jun Lu, Tinsu Pan

Proceedings Volume 6510, Medical Imaging 2007: Physics of Medical Imaging; 65105R (2007) https://doi.org/10.1117/12.709442
Event: Medical Imaging, 2007, San Diego, CA, United States

Abstract

We have developed a ray-tracing backprojection (RTB) to back-project all the detector pixels into the image domain of cone beam CT (CBCT). The underlying mathematic framework is the FDK reconstruction. In this method, every ray recorded by the flat panel detector is traced back into the image space. In each voxel of the imaging domain, all the rays contributing to the formation of the CT image are summed together weighted by each rays' intersection length with the voxel. The RTB is similar to a reverse process of x-ray transmission imaging, as opposed to the conventional voxel-driven backprojection (VDB). In the RTB, we avoided interpolation and pixel binning approximations, achieved better spatial resolution and eliminated some image artifacts. We have successfully applied the RTB in phantom studies on the Varian On Board Imager CBCT. The images of the Catphan CTP404 module show more accurate representation of the oblique ramps in the measurement of slice thickness, and more accurate determination of slice thickness with the RTB than with VDB. The RTB also shows higher spatial resolution than the VDB in the studies of a high contrast resolution phantom.

Citation Download Citation

Jun Lu and Tinsu Pan "A ray-tracing backprojection algorithm for cone beam CT", Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65105R (28 March 2007); https://doi.org/10.1117/12.709442

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available