ABSTRACT
In the 1990s, various ²at panel detectors were developed and used to construct digital x-ray systems for general radiography as well as mammography applications. ™e availability of these detectors facilitated research and development of cone beam computed tomography (CBCT) techniques in academic institutions. With these techniques, a cone shaped beam, like those used in radiography, ²uoroscopy or mammography, is used to rotate around and scan the patient. One of these e›orts was aimed to implement dedicated breast CT using the pendant geometry, with which the patient lies prone on the table with one of her
breasts protruding downward through an opening and scanned by a CBCT system underneath the table. ™e use of CBCT techniques for dedicated BCT was œrst proposed independently by Boone et al. (2001) at the University of California at Davis and Ning et al. (2002) at the University of Rochester (O’Connell et al. 2010, Lindfors et al. 2008, Ning et al. 2007, Boone et al. 2006, Chen and Ning 2002, Boone et al. 2001). ™e former constructed the œrst patient imager for clinical evaluation. ™e latter led to the œrst e›ort to commercialize the BCT technology. Patient studies conducted to date have shown that BCT images are superior to mammography in detecting and visualizing breast anatomy and so¬ tissue masses but are more limited in imaging small microcalciœcations. A third group at the Duke University has recently constructed a patient imager with a specially designed quasimonoenergetic x-ray source to improve the image quality (McKinley et al. 2005, Tornai et al. 2005). Two other groups, one at the University of Massachusetts and the other at ™e University of Texas MD Anderson Cancer Center, have constructed bench top experimental systems to image mastectomy breast specimens in an e›ort to investigate the imaging properties of BCT (O’Conner et al. 2008, Lai et al. 2007, O’Conner et at. 2007, Yang et al. 2007). ™e latter has also proposed and investigated the use of a collimated x-ray beam to scan a preselected volume-ofinterest to allow smaller microcalciœcations or other details to be seen without increasing the integral breast dose (Chen et al. 2009, Lai et al. 2009, Chen et al. 2008). To enhance the visibility
5.1 History of Development............................................................................................................53 5.2 General Design .......................................................................................................................... 54
Gantry and Table • X-Ray Source • Detector • Image Reconstruction 5.3 Image Quality ............................................................................................................................ 56
5.4 X-Ray Techniques and Doses ...................................................................................................59 5.5 Comparison to Other Modalities ............................................................................................59
