The aim of this study is to examine the use of Near Infrared Fluorescence imaging on lymphatic vessels in humans.

Different parameters that reflect lymphatic function will be tested for intra and inter individual reproducibility.

We use 10 healthy test subjects and examine their lymphatic system. All subjects are healthy men between the ages of 20 and 30.

When the fluorescent dye "indocyanine green", has been injected into the skin on the patients feet, it will be transported through the lymph vessels, resulting in clear visualization of the vessels, using a laser and a EM-CCD camera.

On both legs we examine the frequency of vessel contraction and the velocity of lymph moving in vessels. We furthermore use several methods to quantify the vessel function such as the refill time of a vessel, (manually emptied vessel and refill time of 10 cm of a vessel), and pumping pressure (at what pressure lymph can pass a blood pressure cuff).

We investigate the activity of vessels over time, and after several interventions such as exercise, and water baths of the foot at different temperatures.

The patients are examined for approximately 4 hours and wil be examined again 14 days later.

Inclusion Criteria:

Exclusion Criteria:

• lymphedema, edema or vascular disease.

The participants are young healthy males.