Final Progress Report

Proposal No. IBD-0196R
Principal Investigator:  Caroline Cao, Ph.D.
Applicant Organization:  Tufts University (Medford, Massachusetts, U.S.A.)
Project Title:  Image-guided research in colonoscopy to improve diagnosis of inflammatory bowel disease
Period of Award:  February 1, 2007 – January 31, 2009

Summary of Project Aims

The objective of this research was to demonstrate the laboratory feasibility of a new nano-based fiber optic sensor design for tracking the colonoscope. We aimed to develop an affordable and easy to implement flexible sensor that can track its own position and shape. The tracker can then provide 3D data for the purpose of spatial visualization in real-time. The rationale for the proposed research is that, once the shape and position of the colonoscope can be tracked, coupled with effective display design, visualization and navigation in colonoscopy can be more effective. These colonoscopy navigation improvements will lead to improved detection and diagnosis of IBD and potential increase in screening of the at risk population.

Our novel shape tracker would be constructed from a single optical fiber. We use fluorescence dye (i.e., nanocrystals, quantum dots) emission detection techniques to determine the radius and direction of bends along the length of the optical fiber. Our design is unique in that a single optical fiber provides all of the information necessary to fully represent its shape. Its small size enables easy implementation with the current design of colonoscopes. For example, it can be inserted into the biopsy channel of the colonoscope, or embedded in the body of the colonoscope to track the position and shape of the scope in real-time. The position data would then be used to drive a 3D graphical model of the scope in real-time, which would then serve as a navigational aid for the physician during the colonoscopy procedure.

The resultant commercialized product from this research has value for several stakeholders:

  • For the physician, such a shape sensor device can be coupled with a visual guidance system to reduce disorientation during          colonoscopy, lower mental and physical workload in manipulating the scope, better decision-making, and allow more accurate diagnosis. 
  • For the patient, this means that the procedure is shorter, with fewer colon-stretching manoeuvres, and less pain and discomfort. 
  • For the hospital, it means smaller or fewer dosages of anaesthesia, and more patients examined per day. 
  • For the health care system, it means lower healthcare costs due to earlier detection of IBD and colorectal cancer.

Accomplishments towards Project Aims

We have developed and optimised the following:

  1. Fabrication of a sensorized optical fiber with quantum dots
  2. Fabrication of three sensorized fibers in a bundle
  3. Selection differentiable quantum dots for use in shape sensor
  4. Data collection using spectrometer
  5. Data collection using CMOS imager
  6. Data analysis to calculate the degree of bending and direction of bending in the sensorized fiber
  7. Demonstrated proof-of-concept
  8. Patent application filed in US
  9. Market research on commercialisation of technology
Significant Results

 Positive:
  1. Proof of concept and laboratory feasibility developed for single fiber embedded with a limited number of quantum dots.
  2. Alternate approach developed using bundle of fibres and CMOS imaging.
  3. Obtained high accuracy in shape tracker performance for single bend (~5 % error with single bend.
  4. Ascertained clinical interest in product as training tool.

Negative:

  1. Number of commercially available quantum dots is limited.
  2. Market realization requires more information on specific clinical benefits.

Lay Summary of Progress Report

The aim of the project is to show the feasibility of an innovative technology to aid physicians in performing colonoscopy. The technology is an affordable, and easy to implement, flexible sensor that can track its own position and shape, using a modified optical fiber with embedded fluorescent markers. The sensor can track multiple bends along the length of a flexible body, such as the colonoscope. It can be easily integrated into the shaft of the colonoscope, or inserted into the biopsy channel of the scope. Once coupled to the colonoscope, the endoscopic fiber optic shape tracker can track the entire length of the endoscope (as opposed to a single point at the end of the scope) and provide a visual image of the 3D position and shape of the scope in real time. This information will serve as a navigational aid for the physician. The navigational aid can 1) improve the endoscopist’s ability and confidence in performing the procedure, 2) reduce the amount of discomfort and unnecessary pain inflicted on the patient due to scope manipulation, 3) enable the accurate localization of lesions, and 4) increase the screening and diagnosis of IBD.

With the research grant from the Broad Foundation, we have been able to demonstrate the feasibility of the technology. We were successful in developing and optimising our methods for fabricating the fibre optic shape tracker, and for collecting and analysing the data from the tracker. As we are still limited by the number of commercially available fluorescent markers (new material still under development), we have devised an alternate design for the technology. We have also demonstrated the feasibility and the advantages of the new design. We have now developed two different designs for the technology, and two approaches for obtaining the data from the tracker, allowing us flexibility in the implementation of the technology in the clinical environment.