Proof-of-concept Interventional Study to Evaluate the Feasibility of the New Method, LymphMonitor 1.0, to Assess Lymphatic Function, Consisting of Indocyanine Green-based Lymphatic Specific Tracer. and a Custom Fluorescence Measuring Investigational Device LymphMeter 1.0.

Lymphedema is the consequence of injured lymphatic system and is characterized by chronic, often disabling swelling of am affected body part, often arm or leg. In the western world secondary lymphedema arises most commonly after removal lymph nodes in an operation as a part of cancer treatment (for example from the armpits or the groin region), however it may also develop as a result of radiation, any other operation, infection or injury that destroys a part of lymphatic system. The disease often develops even years after the event. While there is no cure for lymphedema at present, early detection would ensure timely physiotherapy and application of compression garments that significantly slow down or stop the progression of the disease. However, presently used methods of that are used for diagnosis and evaluating the stage of the disease, are either invasive and expensive or inaccurate and can only be performed at specialized medical centres.

Therefore, we developed a simple, affordable and accurate technology, LymphMonitor 1.0 that can allow for testing how efficiently the lymphatic system is functioning. The test can be performed at the local medical centre or potentially even at home.

In this study, we investigate whether LymphMonitor 1.0 technology can distinguish between a healthy and a diseased lymphatic system (in lymphedema). This method may allow early diagnosis of lymphedema so that the development of the disease can be detected and prevented early enough. By participating in the study the lymphedema patients are making an important contribution to increasing the quality of life of lymphedema patients. In LymphMonitor 1.0 method method, a solution of a safe fluorescent dye, indocyanine green, is injected painlessly using tiny microneedles, MicronJet600TM, directly into the skin of the arm or leg. After injection, this dye is removed from the skin only through the lymphatic vessels. The intensity of the fluorescence signal corresponds to the amount of dye left in the skin. The decrease in the fluorescence signal after the injection is measured on the surface on the skin using a new device, LymphMeter 1.0. The faster the dye (and that fluorescence signal) disappears from the surface of the skin, the better the lymphatic system works. Therefore in the arm or leg affected by lymphedema the fluorescence signal will decrease much slower compared to the healthy one.