Bragg-Peak Proton-Beam Therapy for Arteriovenous Malformations of the Brain

Abstract

Patients with arteriovenous malformations of the brain, who are subject to disabling or fatal recurrent hemorrhage, seizures, severe headache, and progressive neurologic deficits, may be considered unsuitable for conventional therapies (craniotomy with excision or embolization), usually because of the location, size, or operative risk of the lesion. We have treated such patients with stereotactic Bragg-peak proton-beam therapy and report the follow-up of 74 of the first 75, 2 to 16 years after treatment. Proton-beam therapy is intended to induce subendothelial deposition of collagen and hyaline substance, which narrows the lumens of small vessels and thickens the walls of the malformation during the first 12 to 24 months after the procedure. Two deaths from hemorrhage occurred in the first 12 months after treatment, but no lethal or disabling hemorrhages occurred after this interval. Seizures, headaches, and progressive neurologic deficits were in most cases arrested or improved. Bragg-peak proton-beam therapy appears to be a useful technique for treatment of intracranial arteriovenous malformations, especially those that are unsuitable for treatment by other methods.

Embolization of Cerebral Arteriovenous Malformations with Bucrylate

“…The risk of future hemorrhage is only removed by total elimination of the AVM, which is obtained by surgery with a morbidity of 2 to 11 per cent and a mortality of 2 to 6 per cent in elective, selected cases (1 1, 14, 22). Radiation therapy carries a low risk of complications (18,21,36) and radiosurgery with the stereotactic T o gamma unit has achieved total occlusion in 85 per cent of small AVMs (diameter less than 3 cm) (36). The effect is delayed, however, and usually not seen until 2 years after treatment.…”

“…Depending on the site and size of the AVM, the surgical risk (1 1, 14, 22) may sometimes exceed the natural risk (6,13). In these situations other treatment methods such as radiation therapy (18,21,36) and transarterial embolization may become interesting alternatives. Embolization is used either alone or as an adjunct to the other methods.…”

Comparison of different radiation types and irradiation geometries in stereotactic radiosurgery

“…There has bee11 a recent surge in interest in stereotactic radiosurgery of intracranial lesions, such as arteriovenous malformations (AVMs), tumors and isolated metastases [3,4,6,7,9,11,12,13]. Much experience has been gained at a number of medical centers around the world in the past three decades [1,4,6,8,12,13].…”

“…Much experience has been gained at a number of medical centers around the world in the past three decades [1,4,6,8,12,13]. The successful treatment of tumors and AVMs that were surgically-inaccessible has spawned the dissemination of stereotactic radiosurgical techniques at a number of different institutions.…”

High yields of isochromatid breaks and successive formation of chromosome exchanges may lead to reproductive cell death following high-LET irradiation

“…The Bragg peak is thus unique to the heavy charged High yields of isochromatid breaks and successive formation of chromosome exchanges may lead to reproductive cell death following high-LET irradiation ion particle irradiation, but does not occur in X-rays or g-rays that are utilized in conventional radiation cancer therapy [1]. The Bragg peak of heavy ion irradiation is therefore advantageous for cancer therapy, because the energy selectively attacks tumor cells located in deep body [7,8]. The charged particles also lose energy by ionization and excitation along the track.…”