Fractionated brain stereotactic irradiation using a non‐invasive frame:Technique and preliminary results

摘要

AbstractIn this study we report on the use of two non‐invasive head frames in fractionated stereotactic irradiation for small benign or low grade brain tumors. Sixty‐one patients were treated from April 1988 to December 1992 with external stereotactic irradiation: 12 presented with arteriovenous malformations (AVMs), 32 with benign tumors, and 17 with malignant tumors. Sire of the lesions ranged from 15 to 45 mm in diameter. Two immobilization devices were used: the Laitinen stereoadapter, until December 1992, and then the Beverly frame, specifically designed for radiotherapy. Treatment was given daily, 5 days/week, using 1 or 2 non‐coplanar arcs, the dose per fraction ranging from 2 to 3 Gy. The study of the accuracy of the two frames showed an average discrepancy<1 mm for 25 setups, irrespective of the spatial plane. All the patients tolerated well the immobilization devices. Forty‐one of the 61 patients were followed at least 2 years after the treatment (7 with AVMs, 20 with benign tumors, 14 with malignant tumors). For AVMs, 1 regressed completely, 1 partially decreased in size, and the other 5 remained unchanged. For benign tumors, 14 patients are alive without disease progression, 5 showed a marked tumor decrease, and 1 died of intercurrent disease. For malignant tumors, 3 patients died of their disease, 2 are alive with disease progression, 8 are alive without disease progression, and 1 has a complete tumor regression. From these results we conclude that the Beverly frame is perfectly suited to fractionated stereotactic irradiation. For AVMs, the obliteration rate with fractionated irradiation at low dose is disappointing. These lesions probably require larger single dose treatments to induce vascular sclerosis. For other benign or low grade tumors, the observed results are satisfactory and the progression‐free rate may be as high as that obtained with single fractions with presumably less adverse effects. © Wiley