Light-Tissue Interaction; Optical Coherence Tomography; Spectroscopy

Focus of research

When patients are suspected to have cancer or have follow-up examinations after treatment, their experiences will widely differ depending on the location of the suspected lesion. Some procedures will be minimally invase and highly targeted, for example at the skin where the lesion is in plain sight. Others can be much more invasive because the lesion is hidden inside otherwise normal organ tissue such as the prostate or esophagus.

Dispite these differences, the diagnosis of these lesions has one thing in common: patients have to undergo biopsy where tissue is been taken out to be evaluated under a microscope by a pathologist. Taking biopsies is evidently a burden to the patient, it is both difficult and expensive, and it gives the doctor an incomplete picture because there is no information on the tissue surrounding the biopsy. This motivates me to investigate the potential of optical techniques - such as Optical Coherence Tomography and Single Fiber Reflectance spectroscopy - for cancer detection and diagnostics. 

Functional Optical Biopsy combines optical techniques to get information on tissue anatomy, structure and physiological function at resolutions approaching the cellular level. At the heart of our methods is Optical Coherence Tomography (OCT), an imaging technique that provides micrometer scale 3D images of tissue volumes. Using OCT and Spectroscopic OCT, physiological endpoints as flow, perfusion, oxygenation and biochemical composition can be measured in and around the suspected lesion. Cancer progression leads to changing scattering properties of affected tissues. Single Fiber Reflectance (SFR) spectroscopy detects these changes at small spatial scales, making it a promising tool for early in situ detection especially at locations that cannot be reached with conventional radiological imaging techniques or with OCT. Combined with e.g. (darkfield) reflection spectroscopy and multi-photon fluorescence imaging, even better characterization of suspected lesions will be possible. The doctors can use this information improve the selection of biopsy sites from information from the lesion and improve treatment planning from the information from the lesions surroundings.

The scope my research interests can broadly be summarized in 3 topics:

  • Physical understanding of the optical signals. Absorption and fluorescence spectra reflect the biochemical composition of the tissue. Quantification of these spectra is challenging, especially when measured in patients. Next to these, the measured signals are determined by light scattering, which reflects the nano-scale organization of the tissue. The relation between morphological changes in or between cells and light scattering is not yet completely understood. We address this problem with out-of-the-box modelling of our signals, for example by connecting measured signal statistics (mean, variance, correlation scales) to a statistical descriptions of the sample organization.
  • Novel instrumentation. We aim to evaluate and validate our technology in the only setting that matters: in the clinic, with patients. Instrumentation that is compatible with existing procedures and protocols is thus paramount. In collaboration with our clinical collaborators and partners from industry, we have several exciting projects underway.
  • Clinical application is assured via a close collaboration with several departments within our hospital. OCT debuted in ophthalmology; today we collaborate with the urology department (applications in bladder, kidney, urether, prostate), the department of cardiology and the department of reconstructive surgery, as well as with the gyneacology department of the Dutch Cancer Institute.

[last edited 21/02/2020]