Development and clinical validation of the LymphMonitor technology to quantitatively assess lymphatic function

Current diagnostic methods for evaluating the functionality of the lymphatic vascular system usually do not provide quantitative data and suffer from many limitations including high costs, complexity, and the need to perform them in hospital settings. In this work, we present a quantitative, simple outpatient technology named LymphMonitor to quantitatively assess lymphatic function. This method is based on the painless injection of the lymphatic-specific near-infrared fluorescent tracer indocyanine green complexed with human serum albumin, using MicronJet600TM microneedles, and monitoring the disappearance of the fluorescence signal at the injection site over time using a portable detection device named LymphMeter. This technology was investigated in 10 patients with unilateral leg or arm lymphedema. After injection of a tracer solution into each limb, the signal was measured over 3 h and the area under the normalized clearance curve was calculated to quantify the lymphatic function. A statistically significant difference in lymphatic clearance in the healthy versus the lymphedema extremities was found, based on the obtained area under curves of the normalized clearance curves. This study provides the first evidence that the LymphMonitor technology has the potential to diagnose and monitor the lymphatic function in patients

Portable multi-wavelength fluorescence measurement device

​© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Monitoring-based preventive medicine relies heavily on minimal or noninvasive, portable and cost-effective measurement solutions. This work presents a portable multi-wavelength fluorescence measurement system. The pinhole collimator, Fresnel focusing lens and PIN photo diode provide a cost-effective fluorescent light detection path. The with matte black filament 3D printed housing reduces unwanted reflections along the detection path. The integrated laser diode drivers ensure constant optical output power during operation. This is achieved by utilizing a laser diode package which incorporates both a laser and monitor diode. The monitor diode's output photocurrent is proportional to the optical output power, and thus provides, a feedback path for the driver. An optical diffuser is pre-mounted on each laser diode, providing a uniform illumination of the measurement area. The device adapts to a wide variety of fluorescent dyes by offering exchangeable laser diode modules and support of standard-sized optical thin film filters. The precision integrator transimpedance amplifier applies a switched-input photocurrent measurement technique that ensures the level of sensitivity required for clinical usage. Experimental validation indicates sensitivity in the pico-ampere range. Ex vivo and in vivo measurements, performed by the Faculty of Pharmacy at the Université de Montréal, confirm that the instrument matches its intended application

Portable multi-wavelength fluorescence measurement device : empirical evaluation

Monitoring-based preventive medicine relies heavily on minimal or noninvasive, portable, and cost-effective measurement solutions. In this study, we present a handheld multiwavelength fluorescence measurement system for detection of dermally injected fluorescent tracers. The circular detection area of the device is positioned on the sample containing the fluorescent marker. The marker is excited at regular intervals by a pulse of light. The optical output power is controlled by a laser diode driver, which receives direct feedback on the emitted light intensity from the monitor photodiode integrated into the laser diode package. An optical diffuser is located in front of each laser diode to ensure uniform illumination of the measurement area. Pulsed excitation of the fluorescent tracer allows alternate measurement of foreground and background light intensity. By subtracting the background from the foreground and using a switched-input photocurrent measurement technique, the measured photocurrent represents the actual light emission from the marker. The instrument has interchangeable modules that contain the excitation electronics and emission filter. These modules allow the instrument to be configured for a variety of different fluorescent markers. In vitro measurements show that the device is capable of performing fluorescence measurements for its intended use as a point-of-care device in preventive medicine

Development and Clinical Validation of the LymphMonitor Technology to Quantitatively Assess Lymphatic Function

Current diagnostic methods for evaluating the functionality of the lymphatic vascular system usually do not provide quantitative data and suffer from many limitations including high costs, complexity, and the need to perform them in hospital settings. In this work, we present a quantitative, simple outpatient technology named LymphMonitor to quantitatively assess lymphatic function. This method is based on the painless injection of the lymphatic-specific near-infrared fluorescent tracer indocyanine green complexed with human serum albumin, using MicronJet600TM microneedles, and monitoring the disappearance of the fluorescence signal at the injection site over time using a portable detection device named LymphMeter. This technology was investigated in 10 patients with unilateral leg or arm lymphedema. After injection of a tracer solution into each limb, the signal was measured over 3 h and the area under the normalized clearance curve was calculated to quantify the lymphatic function. A statistically significant difference in lymphatic clearance in the healthy versus the lymphedema extremities was found, based on the obtained area under curves of the normalized clearance curves. This study provides the first evidence that the LymphMonitor technology has the potential to diagnose and monitor the lymphatic function in patients. Keywords: indocyanine green; lymphatic function monitoring; lymphatic system; lymphedema; lymphography; mobile health