Fiber optic probes with self-calibration capability for tissue optical spectroscopy
UV-visible (UV-VIS) diffuse reflectance spectroscopy (DRS) is sensitive to the absorption and scattering properties of biological molecules in tissue and thus can be used as a noninvasive in vivo tool to obtain quantitative information about the physiological and morphological properties of human tissue. Potential clinical applications of UV-VIS DRS include precancer detection and cancer diagnostics, intraoperative tumor margin assessment, and monitoring of tumor response to chemotherapy, to name just a few examples. Calibration of the diffuse reflectance spectrum for instrument response and time-dependent fluctuation as well as interdevice variations is complicated, time consuming, and potentially inaccurate. Current calibration methods cannot correct for real-time system fluctuations, such as variations in the lamp intensity, and thus require at least 30 min for lamp warm up, which is a significant problem in a clinical setting such as the operating room. Second, they can require an additional 10–20 min before or after the clinical measurement for calibration. It is therefore desirable to create a fast, robust, and systematic calibration approach that can be used for correcting tissue optical spectra obtained at different times and with different instruments and probes.
Duke inventors have reported a novel fiber optic probe with a real-time self-calibration capability that can be used for tissue optical spectroscopy. This technology is intended to replace calibration measurements that traditionally need to be performed immediately before or after collecting tissue spectra for applications such as assessing cancerous tissue. The probe has a built-in calibration channel that can be used to record the lamp spectrum and instrument–fiber responses concurrently with tissue measurements. The inventors have demonstrated this technology in a number of clinical studies including breast biopsy diagnosis, cervical cancer diagnosis, breast cancer margin assessment, monitoring response to therapy, and drug discovery and pharmaceutical testing.
- Avoids the pre- or post-calibration measurements typically required for tissue spectroscopy measurements with UV-Vis diffuse reflectance spectroscopy
- Could save 30 minutes of valuable clinical time
- This approach could also be adopted into other optical modalities, such as fluorescence and Raman spectroscopy