The present invention relates generally to optical probes and more particularly to optical probes for use with Optical Coherence Tomography (OCT) and other optical imaging modalities.
OCT is a laser based imaging modality that uses near infrared or infrared laser light to non-destructively image subsurface tissue structures. An imaging depth on the order of millimeters (mm), with a spatial resolution of a few micrometers (μm) is relatively easily achieved using OCT at practical light fluence levels on the order of 100 μW. OCT is therefore very useful for in vitro and in vivo tissue structure imaging applications such as may be used during minimally invasive surgical procedures. Currently, both side-imaging endoscope systems and forward imaging endoscope systems are known.
The construction of a needle endoscope that is capable of performing forward OCT imaging presents very significant design challenges. Current endoscopes are typically more than 5 mm thick. The thickness of such probes, especially when compared with their en face imaging area, e.g., about 2 mm wide, makes them undesirable as a needle endoscope for image-guided surgical procedures. One major challenge of making a thin endoscope lies with the difficulty of designing a probe beam deflection system that is capable of covering a sufficient scan volume while constraining the probe diameter to be less than about 2 mm to minimize the invasiveness of the probe. A reasonable OCT scan volume for providing sufficient image information would be a conical volume that is about 3 mm in length and about 2 mm in diameter at its maximum circumference.
Therefore it is desirable to provide probes such as forward imaging endoscope needles useful for OCT imaging of a scan volume that overcome the above and other problems.