Ovarian cancer model
In a model of ovarian cancer, she and colleagues externalized the ovaries of a mouse, imaged the organs, put them back in, and reassessed them at 8 weeks. “This model develops cancer very quickly,” said Dr. Barton, who once worked for McDonnell Douglas on the Space Station program. At 8 weeks, using fluorescence and targeted agents with a tabletop multiphoton microscopy system, they observed that the proliferation signals of cancer had begun. “So, with an agent targeted to the folate receptor or to other receptors that are implicated in cancer development, we can see that ovaries and fallopian tubes are lighting up,” she said.
With proof of concept established with the mouse study, she and other researchers are drawing from technological advances to create tiny laser systems for use in the clinic to image a variety of structures in the human body. Optics advances include bulk optics and all-fiber designs where engineers can create an imaging probe that’s only 125 microns in diameter, “or maybe even as small as 70 microns in diameter,” she said. “We can do fabrications on the tips of endoscopes to redirect the light and focus it. We can also do 3-D printing and spiral scanning to create miniature devices to make new advances. That means that instead of just white light imaging of the colon or the lung like we have had in the past, we can start moving into smaller structures, such as the eustachian tube, the fallopian tube, the bile ducts, or making miniature devices for brain biopsies, lung biopsies, and maybe being able to get into bronchioles and arterioles.”
According to Dr. Barton, prior research has demonstrated that cerebral vasculature can be imaged with a catheter 400 microns in diameter, the spaces in the lungs can be imaged with a needle that is 310 microns in diameter, and the inner structures of the eustachian tube can be viewed with an endoscope 1 mm in diameter.
She and her colleagues are developing an OCT/fluorescence imaging falloposcope that is 0.8 mm in diameter, flexible, and steerable, as a tool for early detection of ovarian cancer in humans. “It’s now known that most ovarian cancer starts in the fallopian tubes,” Dr. Barton said. “It’s metastatic disease when those cells break off from the fallopian tubes and go to the ovaries. We wanted to create an imaging system where we created a fiber bundle that we could navigate with white light and with fluorescence so that we can see these early stages of cancer [and] how they fluoresce differently. We also wanted to have an OCT system so that we could image through the wall of the fallopian tube and look for that layer thickening and other precursors to ovarian cancer.”
To date, in vivo testing in healthy women has demonstrated that the miniature endoscope is able to reach the fallopian tubes through the natural orifice of the vagina and uterus. “That is pretty exciting,” she said. “The images may not be of the highest quality, but we are advancing.”
Dr. Barton reported having no relevant financial disclosures.