Colon Cancer Investigation in vivo in Mice Using 1^st Generation Combined OCT-LIF Endoscope

A prototype 2 mm diameter endoscope that can simultaneously collect an optical coherence tomography (OCT) image and laser induced flourescence (LIF) spectra was designed, built, and used in preliminary studies of colon cancer in mice. OCT provides cross-sectional structural information at 10-20 um resolution over a 5 mm field to a depth of about 1 mm. LIF spectra provide information about the chemistry and metabolic state of the tissue.

The image to the right shows an OCT image and its associated LIF emission spectra taken with the endoscope on mouse colon tissue. The bar chart (middle) shows the intensity of the selected emission wavelengths (390, 450, 680 nm) at the corresponding positions in the OCT image just above it. The OCT image is 6 mm long and 1 mm deep. Visible features include glass (g) of the endoscope window, mucosal layer (m), boundray between the mucosa and submucosa (sm), boundary between tunica media and adventitia (tm), adventitia (a), and a motion artifact due to breathing (b).

The figure below shows an image of the endoscope with the optics retracted superimposed on an image with the optics extended to the tip. A dime is shown for size comparison.

The figure to the left shows a solid model of the endoscope tip. It illustrates how the LIF excitation fiber (E) and collection fibers (C) sit above the OCT channel (the fiber(O)), stripped of its jacket, passes through the ferrule (F) to contact the GRIN lens (G). Both systems are cemented to a rod prism (P) that reflects the light through the side of a thin walled silica tube(W).

Future developements and experimental plans for this endoscope include:

1. Optimize the device for rapid collection of data from mouse colon
2. Improve the OCT resolution to 1 um
3. Use the endoscope with OCT and LIF contrast agents
4. Use the endoscope to observe colon cancer response to drug treatment

For additional information contact Alex Tumlinson.

Please also refer to Publications for more resources.