A dual-channel endoscope for quantitative imaging, monitoring, and triggering of doxorubicin release from liposomes in living mice

Abstract

Doxorubicin (Dox) is approved for use in liposomal form for the treatment of ovarian cancer. We previously developed a long-circulating Dox formulation in liposomes containing small amounts of porphyrin-phospholipid, which enables on-demand drug release with near-infrared irradiation. In this study, we present and evaluate a dual-modal, dual-channel light endoscope that allows quantitative reflectance and fluorescence imaging for monitoring of local Dox concentrations in target areas. The endoscope consists of two flexible imaging fibers; one to transmit diagnostic and therapeutic light to the target, and the other to detect fluorescent and reflected light. Thus, the endoscope serves for imaging, for light delivery to trigger drug release, and for monitoring drug concentration kinetics during drug release. We characterized the performance of this endoscope in tissue phantoms and in an in vivo model of ovarian cancer. This study demonstrates the feasibility of non-invasive, quantitative mapping of Dox distribution in vivo via endoscopic imaging.

Wide-field optical spectroscopy system integrating reflectance and spatial frequency domain imaging to measure attenuation-corrected intrinsic tissue fluorescence in radical prostatectomy specimens

“…In the SFDI-based reconstruction of absorption and reduced scattering that was reported here, the average errors across both low and high absorption phantom experiments were similar to other studies [54,57,[76][77][78][79]. However, there was a small increase in reconstruction error (+0.5%) for reduced scattering in the high absorption phantom set when compared to the low absorption set.…”

“…This technique is called attenuation-corrected fluorescence (CF) imaging [49]. Such systems have been applied to PpIX quantification for skin cancer characterization [50,51], surgical guidance in neurosurgery [52,53] and photodynamic therapy (PDT) drug concentration monitoring [54]. Real-time CF imaging has also been attained in tissue phantoms [55].…”

Wide‐field optical property mapping and structured light imaging of the esophagus with spatial frequency domain imaging

“…This could be done by incorporating SFDI systems into an open surgical procedure or by modifying endoscopy systems to achieve optical property measurements. Recent work has shown progress in implementing real‐time SFDI in a rigid endoscope and in a flexible endoscope . While these studies are only proofs of concept, they demonstrate feasibility of adapting SFDI for endoscopic assessment of optical properties and improved management of esophageal abnormalities.…”

Review of structured light in diffuse optical imaging

“…Quantitative, noncontact imaging techniques have since been developed for real-time, wide-field acquisition 38 – 40 and have been pushed toward endoscopic implementation 80 , 81 . Models have also been moving toward new speeds and higher accuracy 49 while becoming robust via subdiffuse sensing 45 , 47 .…”

“… – 76 While this brings the standard wide-field system to fruition, efforts by other groups have been made to develop structured illumination endoscopic imaging systems for minimally invasive clinical guidance 77 – 80 Applying standard three-phase SFDI processing to a fiber-contact endoscope system enables high spatial frequency imaging (fx=[2.7 to 14.5] mm−1) for cancer detection [cf. Figs.…”