Detachable coil embolization treats aneurysms and other blood vessel malformations in the brain and other parts of the body, alleviating much of the danger presented by aneurysms. A catheter is inserted into an artery in the leg then maneuvered through the body to the aneurysm's position. Soft detachable coils are inserted through the catheter into the aneurysm. The body responds by forming a blood clot around the coil blocking off the aneurysm. Coils can be used either to block blood flow to the affected area or to fill the aneurysm or fistula, thus preventing a rupture. This procedure is effective in prolonging life and relieving symptoms.