Transcatheter embolization is the practice of introducing material to within the vasculature to induce blood flow occlusions. Transcatheter embolization is effective for treating vessel malformations such as aneurysms, fistulae and bleeding. If left untreated, some of these arteriovenous malformations can ultimately lead to strokes. In addition, transcatheter embolization is an effective therapy for blocking blood flow to tumors or organs, thus starving the target tissues. Specialized particles, such as drug-coated and radiolabeled beads, are used for the targeted delivery of drugs and for radiation therapy, respectively.