Development and evaluation of a three-dimensional freehand endorectal ultrasound system for rectal cancer staging

Endorectal ultrasound is currently the gold standard for the staging of rectal cancer; however, the accurate staging of the disease requires extensive training and is difficult, especially for those clinicians who do not see a large number of patients per year. Therefore, there is a need for a system to assist clinicians in the accurate staging of rectal cancer by providing a quantification of the disease. The techniques discussed herein show quantitative applicability in images containing (1) no tumor, (2) un-radiated tumor, and (3) radiated tumor. When used as a clinical tool, this system will provide the addition of quantitative measures with what is now a user specific process. The practice of unwrapping endorectal ultrasound images qualitatively provides good visualization of the layers of the rectal wall and rectal tumors and supports the continual study of this novel staging system.