Systems and methods for performing medical procedures involving accessing the lymphatic system

A method for treating a patient having a body including vasculature and a lymphatic system including a thoracic duct, comprising:

• injecting one or more therapeutic agents directly into a target treatment site outside the lymphatic system within the patient's body, the one or more therapeutic agents comprising particles sized for preferential transit into the lymphatic system;
• introducing a distal end of a tubular member into the vasculature via a percutaneous access site;
• advancing the tubular member until the distal end of the tubular member is disposed within a junction of a left internal jugular vein and left subclavian vein and adjacent the thoracic duct;
• sealing the thoracic duct using the distal end of the tubular member to isolate the thoracic duct from the junction;
• and
• removing fluid from the thoracic duct through the tubular member to a location exterior to the patient's body, thereby removing particles from the one or more therapeutic agents that have transited into the thoracic duct.