[A new principle and device for radiosurgery using a linear accelerator; its principle, devices and clinical trials].
The authors have developed new devices for stereotactic radiosurgery using a conventional linear accelerator (LINAC). The system of devices consists of a rotatory chair with a base ring holder, a Brown Robert Well's stereotactic apparatus (BRW's apparatus) with a double set of base rings and a number of precise collimators which eliminate penumbra to the greatest extent. A study rotatory chair was manufactured, whose vertical axis of rotation is always set and stable. A strongly built, adjustable holder for the BRW's base ring is attached to the chair. The principle and flow of procedures step by step is as follows; 1). The rotatory chair is carried in under the linear accelerator and the vertical rotatory axis of the chair is precisely adjusted to align with the vertical center of the photon beam from the LINAC. 2) A base ring and a locator of BRW's apparatus are mounted on a patient's head and three coordinates of a target are determined by CT scans. 3) The target indicator of the dummy set of BRW's apparatus is positioned according to X, Y, Z coordinates of the target. The tip of a rod indicator fixed on an instrument bloc on the arc device is precisely adjusted to touch at the tip of the target indicator. 4) The base ring and arc device with rod indicator are transferred together from the BRW's dummy set to the rotatory chair and fixed to the base ring holder. The tip of the rod indicator is precisely adjusted to be positioned at the isocenter of the LINAC. 5) The base ring and arc device are removed and replaced by another base ring mounted on the head of a patient, who is made to sit on the rotatory chair. The target in the brain is now located at the isocenter of the LINAC. Stereotactic radiation is started with rotation of the chair and circular movement of the gantry of the LINAC. The chair is rotated at a speed of 100 degrees per second, and the gantry of the LINAC is moved slowly on a circular trajectory from +115 degrees to -115 degrees. Fourteen cases, including AVM, cavernous angioma, acoustic tumor and glioma have been treated so far. Three cases of large AVM were treated by a combination of artificial embolization and stereotactic radiosurgery.(ABSTRACT TRUNCATED AT 400 WORDS)
Terao
H
H
Department of Neurosurgery, Toho University Medical School.
Nishikawa
H
H
Ooishi
H
H
Endo
T
T
Kaneko
I
I
Kogure
T
T
D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000601:surgery*; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D005910:Glioma / Q000601:surgery; D006392:Hemangioma, Cavernous / Q000601:surgery; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery; D010315:Particle Accelerators / Q000295:instrumentation; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D013238:Stereotaxic Techniques