The purpose of this study was to evaluate the filtering effect of the Gunther tulip retrievable vena cava filter (GTF) during treatment of deep venous thrombosis (DVT) in the lower extremity using various interventional radiological procedures. Subjects of the study were all 17 consecutive patients (8 women, 9 men; age range 18-87 years; mean age 55.9 years) with symptomatic lower limb DVT referred for interventional radiological treatment between February 2001 and September 2004. In all of these patients, the GTF was implanted during interventional radiological treatment. Trapped thrombus in the filter was evaluated with venocavography performed repeatedly during the treatment for DVT. Implantation of a total of 29 GTFs was successfully performed in the 17 patients. In 10 (58.8%), more than 2 filters were subsequently implanted to prolong implantation time. Also in 10 patients, the DVT resolved after therapy and retrieval of the final GTF was successful with one exception. Worsening of or new formation of pulmonary embolism was avoided in all patients. In 8 (47.1%) of the 17 patients, a trapped thrombus in the GTF was observed during treatment for DVT. In six patients the trapped thrombus was large, filling more than half the height of the filter. In conclusion, we found that the GTF is effective in filtering the relieved thrombus from DVT in the lower extremity and in protecting against movement of the thrombus to the pulmonary artery during therapies with interventional radiological procedures.