2D-3D registration for prostate radiation therapy based on a statistical model of transmission images
Abstract
In external beam radiation therapy of pelvic sites, patient setup errors can be quantified by registering 2D projection radiographs acquired during treatment to a 3D planning computed tomograph (CT). We present a 2D-3D registration framework based on a statistical model of the intensity values in the two imaging modalities. The model assumes that intensity values in projection radiographs are independently but not identically distributed due to the nonstationary nature of photon counting noise. Two probability distributions are considered for the intensity values: Poisson and Gaussian. Using maximum likelihood estimation, two similarity measures, maximum likelihood with a Poisson (MLP) and maximum likelihood with Gaussian (MLG), distribution are derived. Further, we investigate the merit of the model-based registration approach for data obtained with current imaging equipment and doses by comparing the performance of the similarity measures derived to that of the Pearson correlation coefficient (ICC) on accurately collected data of an anthropomorphic phantom of the pelvis and on patient data. Registration accuracy was similar for all three similarity measures and surpassed current clinical requirements of 3 mm for pelvic sites....Continue Reading
References
Citations
Related Concepts
Related Feeds
Aphasia
Aphasia affects the ability to process language, including formulation and comprehension of language and speech, as well as the ability to read or write. Here is the latest research on aphasia.