Indocyanine Green (ICG) lymphography is a relatively new imaging technique that allows for quick visualization of superficial lymph flow in real-time, without radiation exposure. This imaging is useful for diagnosing and assessing lymphedema. ICG lymphography has a higher sensitivity and specificity than lymphoscintigraphy, the current gold standard imaging device for lymphedema. ICG lymphography precisely and reliably diagnoses, tracks, and stages lymphedema severity, ranging from subclinical or early lymphedema to more advanced cases. The ICG contrast dye used to visualize the lymphatic system takes approximately six hours to plateau. Therefore, patients must wait six hours between their initial and delayed scans.

The purpose of this study is to determine if exercising on a Nu-step device between ICG initial and delayed scans would shorten the period of time a patient had to spend at the hospital on the day of their ICG lymphography.

The general procedures for this involve (after selecting subjects, consenting subjects, educating the subject on the protocol, along with other appropriate measures):

• Taking baseline vitals (HR & SpO2) and limb circumference measurements

• 5-minute period of time to acquaint subject with the exercise equipment (Nu-Step) at any level of exertion

• injection of contrast agent to allow for visualization of the superficial lymphatic system by a qualified nurse

• Initial scan

• A 5-minute period of exercise at "moderate" level of exercise (This correlates to the rating of perceived exertion levels of 12-13; All exercise periods should be at this level and will be monitored by a provider)

• Second scan & vitals

• 5-minute period of exercise

• Third scan & vitals

  o Continue 5-minute exercise period followed by scan & vitals until disease pattern emerges

  * Exercise for 5 minutes then scan and vitals until images reach steady state for two consecutive scans

• Final vitals (HR & SpO2)

  * Repeat scan every 1 hour until the normal 6 hour scan to monitor for further changes in lymphatic pattern.

• Exit survey

Following consent, the patients will answer the questions in the screening questionnaire and this data will be collected. Patients that do not screen out of the study (i.e. meet all inclusion criteria and none of the exclusion criteria) will continue with the study. Individuals who meet the exclusion criteria will not continue.

Study participants will be asked to go to the Rehabilitation Therapies clinic on the lower level of the main hospital for a one time visit. The visit will take approximately three to six hours.

During the visit, height and weight will be measured. Circumference measurements of the arms and legs will also be measured with a measuring tape. Bioimpedance analysis of the limb will be performed to assess the fluid content in the limbs.

Pain Ease numbing spray will have been applied to three injection sites on the affected arm or leg. 0.1ml of 0.25% Indocyanine green (ICG) dye will then be injected into the distal arm or leg at three separate sites: two interdigital injections and one injection in the volar wrist or posterior to the medial malleolus.

An immediate scan will be acquired using an ICG lymphography device. The scan will take approximately five minutes to complete. The data from this image will be considered baseline. This image is part of the patient's normal care at our institution and would be done even if the subject was not in this study.

The participant will then use the Nu-Step exercise machine for five minutes at a rate of perceived exertion (RPE) of 12-13. Heart rate will be monitored during the exercise with a pulse oximeter. After five minutes, a delayed scan will be performed with the NOVADAQ SPY Elite System and data will be recorded. The participant will continue to exercise for five minutes at an RPE of 12-13 and be scanned after every five minutes until the scans show no change in lymph pattern after two consecutive scans. The patient will be undergoing scanning and be exercising for a maximum of one hour.

Limb circumference measurements and bioimpedance scans will be repeated after exercise has been completed. The scan will be repeated every 1 hour until the normal 6-hour scan to monitor for further changes in the lymphatic pattern.

A post-intervention questionnaire will then be provided to the participant to complete discussing their exercise experience that day during the study, their previous ICG experiences, and their preference between this protocol and the current scanning process.

During the study, the subject will be told when he/she is being photographed/recorded. The injections and scans are clinically-indicated and would occur whether the individual was in the study or not. The initial and last scans are clinically indicated to determine disease status. 3) clarify how the follow-up survey is completed via email

Inclusion Criteria:

• Female patients
• Suspected lymphedema or previously diagnosed lymphedema
• Between the ages of 18-85 years old.

Exclusion Criteria:

• Allergies to iodine
• pregnant
• nursing
• On daily heart medication
• Have medical conditions affecting the heart, lungs or joint conditions that prevent prolonged physical activity of the arms or legs.

6 months