Transcatheter arterial infusion has improved the preoperative control of osteosarcoma. The conventional radiographs and angiograms of osteosarcoma were evaluated in 53 patients before and after treatment. In the responders, two types of calcifications representing healing are observed: peripheral and central. The calcification is readily differentiated from that of tumor new bone. Angiography revealed a decrease in tumor vascularity and stain in responding tumors. Excellent angiographic and pathologic correlation of these changes is presented.