A clinical instrument for combined raman spectroscopy‐optical coherence tomography of skin cancers

Abstract

Background and Objective The current standard for diagnosis of skin cancers is visual inspection followed by biopsy and histopathology. This process can be invasive, subjective, time consuming, and costly. Optical techniques, including Optical Coherence Tomography (OCT) and Raman Spectroscopy (RS), have been developed to perform non-invasive characterization of skin lesions based on either morphological or biochemical features of disease. The objective of this work is to report a clinical instrument capable of both morphological and biochemical characterization of skin cancers with RS-OCT. Materials and Methods The portable instrument utilizes independent 785 nm RS and 1310 nm OCT system backbones. The two modalities are integrated in a 4” (H) × 5”(W) × 8”(L) clinical probe. The probe enables sequential acquisition of co-registered OCT and RS data sets. The axial response of the RS collection in the skin was estimated using scattering phantoms. In addition, RS-OCT data from patients with cancerous and non-cancerous lesions are reported. Results The RS-OCT instrument is capable of screening areas as large as 15 mm (transverse) by 2.4 mm (in depth) at up to 8 frames/sec with OCT, and identifying locations to perform RS. RS signal is collected from a 44 µm transverse spot through a depth of approximately 530 µm. RS-OCT data sets from a superficial scar and a nodular BCC are reported to demonstrate the clinical potential of the instrument. Conclusion The RS-OCT instrument reported here is capable of morphological and biochemical characterization of cancerous skin lesions in a clinical setting. OCT can visualize microstructural irregularities and perform an initial morphological analysis of the lesion. The images can be used to guide acquisition of biochemically specific Raman spectra. The two data sets can then be evaluated with respect to one another to take advantage of the mutually complimentary nature of RS and OCT.

Raman spectroscopy: techniques and applications in the life sciences

“…Patil et al used the same spectrograph and CCD to detect both OCT and Raman signals [71]. Their instrument was used to detect skin cancer [445].…”

Optical coherence tomography—current technology and applications in clinical and biomedical research

“…It provides a chemical fingerprint of a sample, that can be used to distinguish diseased tissue from healthy [254,255], and is especially promising for diagnosis of early stage cancer or pre-cancer conditions [256,257]. Patil et al showed that data from Raman spectroscopy can help to accurately classify skin lesions when OCT images alone are ambiguous [258,259].…”

Multimodal optical coherence tomography and fluorescence lifetime imaging with interleaved excitation sources for simultaneous endogenous and exogenous fluorescence

“…Optical Coherence Tomography (OCT), confocal reflectance microscopy, or Optical Coherence Microscopy (OCM), with a modality that probes the biochemistry, e.g. fluorescence or Raman microscopy [6][7][8]. For instance, OCT has been combined with fluorescence imaging for the detection of atherosclerosis [9,10], colon cancer [11], and early bladder cancer [1].…”