Junguo Bian PhD, Presenter: Nothing to Disclose

Jiong Wang PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV Stockholder, Koninklijke Philips Electronics NV

Xiao Han MSC, Abstract Co-Author: Nothing to Disclose

Emil Y. Sidky PhD, Abstract Co-Author: Nothing to Disclose

Ling-Xiong Shao PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV Stockholder, Koninklijke Philips Electronics NV

Xiaochuan Pan PhD, Abstract Co-Author: Research Grant, Koninklijke Philips Electronics NV Research Grant, Toshiba Corporation Research Grant, General Electric Company

In SPECT/CT, and in image-guided radiation therapy and surgery, CBCT unit often uses an offset-detector configuration for increasing the field of view (FOV). The inclusion of CT unit in SPECT/CT promises an added-on value to SPECT imaging by providing patient anatomy information and attenuation map. However, CT radiation dose involved is a concern. CT-radiation dose can be lowered through reducing the number of projections required by FBP-based algorithms. We develop iterative algorithms for accurate image reconstruction from low-dose data collected at a reduced-number of views in offset-detector CBCT imaging.

Both phantom and patient data sets were acquired with the CBCT unit at 720 views evenly spaced over 2pi. We extracted sparse-view data at 72, 120, 180, and 360 views from 720-view data. We formulated image reconstruction in offset-detector CBCT as optimization problems involving minimizing image total variation (TV) subject to data and other constraints, and developed TV-minimization iterative algorithms that can accommodate the offset-detector geometry to reconstruct images from sparse-view data through solving the problems. Using FBP-based reconstruction from 720-view data as a reference, we performed visualization and task-specific evaluation of algorithms proposed.

Results of the study demonstrate that, depending upon imaging tasks, the proposed TV-minimization iterative algorithm can reconstruct images of potential utility from a small fraction of the data used in current SPECT/CT scans.

Our study indicates that the developed TV-minimization iterative algorithm can yield images of practical utility from sparse-view data and can thus reduce imaging radiation dose in CBCT.

Dose reduction for offset-detector CBCT can have impacts for SPECT/CT, and image-guided radiation therapy and surgery where this configuration is used.

Bian, J, Wang, J, Han, X, Sidky, E, Shao, L, Pan, X, TV-Minimization-based Iterative Image Reconstruction With an Offset-Detector CBCT in SPECT/CT.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029436.html