Fluorescence-enhanced optical imaging on three-dimensional phantoms using a hand-held probe based frequency-domain intensified charge coupled device (ICCD) optical imager

Fluorescence-enhanced optical imaging is an emerging non-invasive and non-ionizing modality towards breast cancer diagnosis. Various optical imaging systems are currently available, although most of them are limited by bulky instrumentation, or their inability to flexibly image different tissue volumes and shapes. Hand-held based optical imaging systems are a recent development for its improved portability, but are currently limited only to surface mapping. Herein, a novel optical imager, consisting primarily of a hand-held probe and a gain-modulated intensified charge coupled device (ICCD) detector, is developed towards both surface and tomographic breast imaging. The unique features of this hand-held probe based optical imager are its ability to; (i) image large tissue areas (5×10 sq. cm) in a single scan, (ii) reduce overall imaging time using a unique measurement geometry, and (iii) perform tomographic imaging for tumor three-dimensional (3-D) localization. Frequency-domain based experimental phantom studies have been performed on slab geometries (650 ml) under different target depths (1-2.5 cm), target volumes (0.45, 0.23 and 0.10 cc), fluorescence absorption contrast ratios (1:0, 1000:1 to 5:1), and number of targets (up to 3), using Indocyanine Green (ICG) as fluorescence contrast agents. An approximate extended Kalman filter based inverse algorithm has been adapted towards 3-D tomographic reconstructions. Single fluorescence target(s) was reconstructed when located: (i) up to 2.5 cm deep (at 1:0 contrast ratio) and 1.5 cm deep (up to 10:1 contrast ratio) for 0.45 cc-target; and (ii) 1.5 cm deep for target as small as 0.10 cc at 1:0 contrast ratio. In the case of multiple targets, two targets as close as 0.7 cm were tomographically resolved when located 1.5 cm deep. It was observed that performing multi-projection (here dual) based tomographic imaging using a priori target information from surface images, improved the target depth recovery over using single projection based imaging. From a total of 98 experimental phantom studies, the sensitivity and specificity of the imager was estimated as 81-86% and 43-50%, respectively. With 3-D tomographic imaging successfully demonstrated for the first time using a hand-held based optical imager, the clinical translation of this technology is promising upon further experimental validation from in-vitro and in-vivo studies.

Rapid inline derivatization of primary and secondary amine containing drugs by capillary electrophoresis with laser-induced fluorescence

Despite the ongoing "war on drugs" the seizure rates for phenethylamines and their analogues have been steadily increasing over the years. The illicit manufacture of these compounds has become big business all over the world making it all the more attractive to the inexperienced "cook". However, as a result, the samples produced are more susceptible to contamination with reactionary byproducts and leftover reagents. These impurities are useful in the analysis of seized drugs as their identities can help to determine the synthetic pathway used to make these drugs and thus, the provenance of these analytes. In the present work two fluorescent dyes, 4-fluoro-7-nitrobenzofurazan and 5-(4,6-dichlorotriazinyl)aminofluorescein, were used to label several phenethylamine analogues for electrophoretic separation with laser-induced fluorescence detection. The large scale to which law enforcement is encountering these compounds has the potential to create a tremendous backlog. In order to combat this, a rapid, sensitive method capable of full automation is required. Through the utilization of the inline derivatization method developed whereby analytes are labeled within the capillary efficiently in a minimum span of time, this can be achieved. The derivatization and separation parameters were optimized on the basis of a variety of experimentally determined factors in order to give highly resolved peaks in the fluorescence spectrum with limits of detection in the low µg/mL range.