Time-domain 3D localization of fluorescent inclusions in a thick scattering medium

Julien Pichette; Éric Lapointe; Yves Bérubé-Lauzière

doi:10.1117/12.807669

12 August 2008 Time-domain 3D localization of fluorescent inclusions in a thick scattering medium

Julien Pichette, Éric Lapointe, Yves Bérubé-Lauzière

Proceedings Volume 7099, Photonics North 2008; 709907 (2008) https://doi.org/10.1117/12.807669
Event: Photonics North 2008, 2008, Montréal, Canada

Abstract

We introduce an improved approach in the 3D localization of discrete fluorescent inclusions in a thick scattering medium. Previously our approach provided accurate localization of a single inclusion, showing the potential for direct time-of-flight fluorescence diffuse optical tomography. Here, we localize various combinations of multiple fluorescent inclusions. We resort to time-domain (TD) detection of emitted fluorescence pulses after short pulse laser excitation. Our approach relies on a signal processing technique, dubbed numerical constant fraction discrimination (NCFD), for extracting in a stable manner the arrival time of early photons emitted by one or many fluorescent inclusions from measured time-of-flight (TOF) distributions. Our experimental set-up allows multi-view tomographic optical TD measurements over 360 degrees without contact with the medium. It uses an ultra-short pulse laser and ultra-fast time-correlated single photon counting (TCSPC) detection. Fluorescence time point-spread functions (FTPSFs) are acquired all around the phantom after laser excitation. From measured FTPSFs, the arrival time of a fluorescent wavefront at a detector position is extracted with our NCFD technique. Indocyanine green (ICG; absorption peak = 780nm, emission peak = 830nm) is used for the inclusions. Various experiments were conducted with this set-up in a stepwise fashion. First, single inclusion experiments are presented to provide background information. Second, we present results using two inclusions in a plane. Then, we move on with two inclusions located in different planes. Finally, we show results with a plurality of inclusions (>2) distributed at arbitrary positions in the medium. Using an algorithm we have developed and tested on the acquired data, we successfully achieve to locate the inclusions. Here, results are obtained for discrete inclusions. In a close future, we expect to extend our method to continuous fluorescence distributions.

Citation Download Citation

Julien Pichette, Éric Lapointe, and Yves Bérubé-Lauzière "Time-domain 3D localization of fluorescent inclusions in a thick scattering medium", Proc. SPIE 7099, Photonics North 2008, 709907 (12 August 2008); https://doi.org/10.1117/12.807669

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available