title: A preliminary investigation of local tomography for megavoltage CT imaging.
abstract: We investigate the problem of reconstructing a two-dimensional (2-D) cross-sectional image of a tumor volume from a set of truncated MV projections that are produced by radiation therapy treatment beams. Our proposed approach is conceptually distinct from previously investigated approaches in that it utilizes a noniterative local tomography reconstruction algorithm. A local tomography reconstruction algorithm is implemented and systematically investigated using several sets of simulated and experimental MV projection data. We demonstrate that the conventional (nonlocal) filtered backprojection reconstruction algorithm cannot, in general, accurately reconstruct the edges and boundaries of low-contrast features from truncated MV projection data. We demonstrate that the local tomography algorithm is not adversely affected by projection truncation and can reconstruct accurately the boundaries of low-contrast structures within the region of interest from truncated MV projections.
authors.affiliation: Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, USA. anastasio@iit.edu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Anastasio
authors.forename: Daxin
authors.initials: D
authors.lastname: Shi
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Pan
authors.forename: Charles
authors.initials: C
authors.lastname: Pelizzari
authors.forename: Peter
authors.initials: P
authors.lastname: Munro
mesh_terms: D000465:Algorithms; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D003198:Computer Simulation; D005240:Feasibility Studies; D006801:Humans; D019047:Phantoms, Imaging; D010865:Pilot Projects; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*