AVMの放射線治療

-CTセットアップによる小照射野分割照射-

抄録

The management of surgically inaccessible, deep-seated arteriovenous malformations of the brain is one of the most challenging subjects in the field of radiation therapy. It is necessary that high doses be confined to the nidus with accurate patient set-up. So far ten patients with this disease have been treated using the CT-linac online system in the department of Radiology, University of Tokyo. A linear accelerator and a gantry of the CT scanner are installed face to face in the same treatment room and they share a communal couch. For the extremely accurate radiation of this disease, a special set-up method with this system, called internal reference set-up, has been developed. In this technique, CT image should be taken before radiation, then the couch rotates and travels toward the treatment machine. Finally the center of the tumor as determined on the CRT of the CT scanner is automatically placed onto the isocenter of the linear accelerator. Treatment result was quite favorable and this technique proved to be effective particularly for radiation therapy of small arteriovenous malformations of 2 cm or less in diameter. The treatment method, including the fractionation schedule as well as clinical feasibility of this technique, are discussed in this report.