Chapter 11 Ultimately, it is expected that the risk of intraoperative iatrogenic injury, especially during minimally invasive surgical procedures, will decrease as the surgeon can be provided with a clearer and increased in‐depth understanding of the whereabouts of vital anatomical structures during surgical dissection25. Spectroscopy and Hyperspectral imaging: limitations and future perspectives With the explorative studies on ex vivo and in vivo spectroscopy in this thesis, wide‐band 174 (350 – 1830 nm) spectral signatures of several human tissue types were revealed. Regarding the spectral analysis of these data, predefined spectral wavelengths related to three predominant tissue parameters (oxygenated/deoxygenated hemoglobin, water and fat) were applied to extract distinctive spectral features. The relevance of these three parameters with respect to spectroscopic data processing is underlined by a recent review article by Bydlon et al.40. These are the three most common endogenous chromophores in the human body and also the most utilized parameters in all of the clinical studies using DRS. The spectroscopic measurements in this thesis were confined to single‐spot data acquisition. A surgeon’s judgment regarding anatomical navigation is not solely based on color spectral information, but also relies on the recognition of the spatial anatomical position of a specific tissue. Therefore, future work needs extension from spot‐wise data acquisition to spectral image acquisition of the full surgical field. In other words, translation of the DRS findings to multispectral or hyperspectral imaging is needed before surgical image‐enhancement can be achieved. For this ultimate goal the first steps have been taken by the studies described in this thesis. Based on the results of the in vivo spectral analyses we now have clues to what sensor detector ranges (i.e., Si‐ and/or InGaAs‐sensors), tissue‐specific (e.g. nerve, ureter, artery, parathyroid) contrast‐enhancement is feasible to investigate. When considering probe‐based spectroscopy for clinical implementation, a DRS system and the associated optical probes will have to be manufactured on a large scale. Safety regulations have to be met before a probe is suitable for commercial use. The custom developed optical probe as used in the studies described in this thesis, was already CE marked and available for sterile applications during surgery. To facilitate large scale manufacturing of optical systems, a reduction in costs and complexity is needed. Furthermore, calibration of a DRS system, which is currently necessary each time prior to use, is time‐consuming and not desirable as an additive optical tool should decrease the procedural time. This problem could be solved by an automatic internal calibration.
proefschrift_Schols_SLV
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