Noncontact recognition of fluorescently labeled objects in deep tissue via a novel optical light beam arrangement

PLoS One. 2018 Dec 19;13(12):e0208236. doi: 10.1371/journal.pone.0208236. eCollection 2018.

Abstract

To date, few optical imaging systems are available in clinical practice to perform noninvasive measurements transcutaneously. Instead, functional imaging is performed using ionizing radiation or intense magnetic fields in most cases. The applicability of fluorescence imaging (e.g., for the detection of fluorescently labeled objects, such as tumors) is limited due to the restricted tissue penetration of light and the required long exposure time. Thus, the development of highly sensitive and easily manageable instruments is necessary to broaden the utility of optical imaging. To advance these developments, an improved fluorescence imaging system was designed in this study that operates on the principle of noncontact laser-induced fluorescence and enables the detection of fluorescence from deeper tissue layers as well as real-time imaging. The high performance of the developed optical laser scanner results from the combination of specific point illumination, an intensified charge-coupled device (ICCD) detector with a novel light trap, and a filtering strategy. The suitability of the laser scanner was demonstrated in two representative applications and an in vivo evaluation. In addition, a comparison with a planar imaging system was performed. The results show that the exposure time with the developed laser scanner can be reduced to a few milliseconds during measurements with a penetration depth of up to 32 mm. Due to these short exposure times, real-time fluorescence imaging can be easily achieved. The ability to measure fluorescence from deep tissue layers enables clinically relevant applications, such as the detection of fluorescently labeled malignant tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fluorescence
  • Humans
  • Lasers*
  • Optical Imaging / methods*
  • Phantoms, Imaging*

Grants and funding

This work was funded by the Research Campus M2OLIE funded by the German Federal Ministry of Education and Research (BMBF, Funding Code 13GW0091B, 13GW0091A and 13GW0091E) and the German Federation of Industrial Research Associations (AiF Project GmbH, Funding Code KF2035759AK3, KF3273101AK3 and KF3086202AK3). The funders had no rule in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Links: Federal Ministry of Education and Research: https://www.bmbf.de/, AiF Project GmbH: https://www.aif.de/home.html. Bruker BioSpin MRI GmbH and ProxiVision GmbH provided support in the form of salaries for authors JW and BM respectively, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.