Research assistant Donald Chau demonstrates the 3-D technology that radiologist Judy Yee pioneered. Photo by Noah Berger
Colonoscopies, though they are the most effective in preventing and treating colon cancer, are one of the most formidable procedures to undergo.
Judy Yee, MD, is the Chief Radiologist at San Francisco Veterans Affairs Health Care System, Professor and Vice Chair of the Department of Radiology and Biomedical Imaging at the University of California San Francisco. Dr. Yee has ameliorated conventional colonoscopies to create graphical software and scanning technology for a less invasive procedure. The technology is known as computed tomography colonography (CTC) or virtual colonoscopy.
The image of a patient’s colon is created from slices of a computed tomography (CT) scan and appears three-dimensional on a flat screen. Using 3-D technology and a laser stylus, the images transform into video, enabling Dr. Yee to isolate and examine every detail of the intestine without invasive cameras. While moving through the intestine, a screen with stereoscopic optical technology tracks her 3-D glasses, bringing her brain to create a virtual holographic image that recreates the dimensions of the human anatomy. The stylus works with advanced graphical processing of the CTC image allowing Dr. Yee to “grab” the portion of the scan she wants to examine more closely and interact with it in 3-D space.
“As the equipment evolves, it allows us to view the same disease processes in a completely different way so we can improve detection and diagnostic ability and streamline workflow. This could go a long way toward helping show what radiology can bring to patient diagnosis and management for all different parts of the body,” said Dr. Yee.
Yee’s holographic imaging platform study is in phase I, with CTC scans from 300 patients ready and training of participating radiologists in progress. UCSF’s 3-D Imaging Lab is directed by Yee and is where she developed the virtual holographic CTC process. The lab blends the application of advanced imaging with research and the education of trainees from UCSF and around the world.
CTC scanning takes 20 seconds, with no sedation necessary and requires 10 ounces of the pre-scan laxative. The test involves a small tube being inserted a few inches into the colon to inflate it with carbon dioxide. Dr. Yee said with CTC scanning there’s a lower frequency of complications, and you can come in first thing in the morning and then go about your daily activities afterward.
Conventional testing for colon cancer was not reducing morbidity and mortality, and cancer rates in some areas were increasing. Many individuals were not coming in to get screened for a malignancy that essentially could be prevented. There’s a fear of the invasive procedure Dr. Yee said.
In 2015, approximately 132,700 new cases of colorectal cancer and 49,700 deaths occurred in the United States, according to the American Cancer Society. The invasive method currently used to perform colonoscopies continues to deter patients from undergoing the procedure. Despite a 90% survival rate when colorectal cancer is detected early, less than half of those who should get screened for colorectal cancer do so.
Dr. Yee is a promoter of CTC and believes CTC should be the frontline colorectal cancer screening tool, with only those patients who have a lesion sent on to the more invasive colonoscopy. Dr. Yee and her colleagues are currently working to remove a financial hurdle to CTC access. Medicare refuses to reimburse for the procedure though numerous private insurers cover it. CTC test costs less than conventional colonoscopy but many Medicare patients may not be able pay for the procedure out of pocket.
