Evaluation of reconstruction accuracy of cone beam volume CT breast imaging for different scanning orbits

Abstract

Conventional screen film mammography is the most effective tool for the early detection of breast cancer currently available. However, conventional mammography has relatively low sensitivity for detecting small breast cancers (under several millimeters). Specificity and the positive predictive value of mammography remain limited owing to an overlap in the appearance of benign and malignant lesions, and surrounding structure. We propose to address the limitations accompanying conventional mammography by incorporating a cone beam volume CT (CBVCT) reconstruction technique with a recently developed flat panel detector. In this study, we present the results obtained from a computer simulation study and a breast-imaging phantom experimental study to find out the reconstruction accuracy of different cone beam volume scanning orbits for CBVCTBI, and to determine if different partial scan protocols (less than 360°) are appropriate for breast cancer detection. Three types of CBVCTBI scanning orbits were simulated using an uncompressed breast phantom. The reconstruction accuracy was evaluated as a function of different scanning orbits assuming reconstruction with 360° was the gold standard. The results indicate that with 180° plus cone angle orbit, the reconstruction error is below 4% that is in the acceptable range. In addition, a preliminary phantom study using both 360° and 180° plus cone angle orbits, was conducted on the current flat panel detector-based CBVCT prototype scanner. The companion CBVCT reconstruction images of an uncompressed breast-image phantom are presented.