BRACHYTHERAPY WITH IR-192 HDR TO PREVENT FROM RESTENOSIS IN PERIPHERAL ARTERIES - AN UPDATE

The use of stents does not appreciably improve restenosis (usually res ulting from intimal hyperplasia) as compared to percutaneous translumi nal angioplasty (PTA) alone. The development of small-caliber probes f or afterloading: therapy in the biliary tract allowed us to use these for therapy in the vascular system. Using a special 9 F catheter, exac t measurement of the length of the stented vascular segment and of the insertion length of the afterloading probe could be reproducibly perf ormed. We used a Nucletron (Micro) Selectron HDR planning system versi on 10.10 for exact calculation, monitoring, and control of the after l oading procedure. Our source was iridium 192 (10 Ci) with a diameter o f 1.1 mm. The program controls and monitors the insertion and removal of the iridium probe from the source into the special catheter through to the tip, and monitors the irradiation duration. The exposure time was around 200 seconds for a surface dose of 12 Gy. To date, a total o f 40 patients have been treated with endovascular afterloading. All pa tients suffered from clinically relevant reocclusions or restenoses in stented vascular segments of the superficial femoral artery following successful PTA or laser treatment, within 6 to 8 months after the las t therapy. In all patients it was possible to perform re-PTA treatment without remaining residual stenoses in the stented region. The additi onal lime required as compared to PTA alone was approximate Ip 45 minu tes with most of this time spending for transportation between the cat h lab and afterloading room. The follow-up period of the 40 patients r anged from 4 months to 71/2 years. In 33 patients, there was no deteri oration of the clinical stage and no restenosis. One patient suffered from an acute thrombosis approximately 3 months after stent implantati on, another patient had a stenosis 3 cm above the stented vascular seg ment 12 months after irradiation treatment. Follow-up examinations hav e revealed no evidence of nerve lesions following irradiation therapy. The tissue surrounding the artery showed no change following irradiat ion therapy, either in the CT,color-coded Doppler, endovascular ultras onic scan or MRI. No complaints of discomfort were reported during or after irradiation. With the exceptions mentioned above. there was no e vidence of any complications.