Interstitial stereotactic radiosurgery

Stereotactic radiosurgery by means of interstitial application of either radionuclides or radiation devices has been used extensively in primary and secondary brain tumors. A few centers have gained sufficient expertise and clinical data to scientifically evaluate this treatment modality. Interstitial stereotactic radiosurgery is limited to circumscribed lesions with a diameter of 3.5 cm or less. The radiobiology of interstitial radiosurgery is quite well elaborated as to doses, dose rates and effects on vascular physiology. Efficacy in low grade gliomas is well documented by several European centers using 125-J sources. Different modes of implantation have been used and evaluated including single fraction treatment using a miniature linear accelerator (Photoelectron). In malignant gliomas interstitial radiosurgery has been investigated in a prospective, randomised, controlled trial and not shown to be effective. Steretactic interstitial radiosurgery is a powerful treatment option in circumscribed CNS tumors like some low grade gliomas and metastasis but does play no major role in the treatment of malignant glioma.