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The preliminary results obtained in 19 patients treated with interstitial irradiation for malignant gliomas are reported. Three different groups are included in the study: I Newly diagnosed tumours not suitable for surgery: 13 cases (10 anaplastic astrocytomas (AA) and 3 glioblastomas (GBM), mean volume 46.56 cc, source Ir 192) were implanted permanently (n = 11, mean peripheral dose 93.54 Gy) or temporarily (n = 2, 50 Gy = 0.5 Gy/hr). External beam irradiation was additionally applied in all cases. II Residual or recurrent tumours: 5 patients (2 AA and 3 GBM, mean volume 7.2 cc, source Ir 192) received temporary implants (150 Gy peripheral dose = 1.5 Gy/hr) after surgery and conventional radiotherapy. III Newly diagnosed surgically removable tumours: only one patient with AA (15 cc volume, source Ir 192) received temporary implantation with the same dose regimen used in Group II before surgery and external beam irradiation.

Quantitative tumour growth into the brain (stage of the disease) and qualitative tumour evolution in the time (progression) are the two basic aspects of the natural history of the cerebral neoplastic disease. Recently the development of neuroradiological imaging (CT and MR) and the progress in biopathology of the nervous system tumours introduced new concepts like heterogeneity of neuroepithelial tumours or evolution to anaplasia. The findings obtained in 159 neuroepithelial tumours studied with stereotactic biopsy from 1980 to 1987 are presented. Most of them were glioblastomas (n = 43; 27%) and astrocytic tumours (n = 81; 50.9%). Twenty-nine cases of fibrillary astrocytomas (35.8% of all astrocytic tumours) showed focal anaplasia (progression). In 10 out of the 43 glioblastomas (23.3%) signs of astrocytic differentiation were clearly evident (secondary glioblastoma?).

Between 1980 and 1987 thirty patients harbouring cerebral neuroepithelial tumours have been treated with stereotactic brachycurie therapy (18 males, 12 females), either alone (n = 16) or combined with surgery (n = 7) and/or external radiotherapy (n = 10). There were 25 slowly growing tumours (grade I n = 1; grade II n = 24). The remaining 5 were malignant tumours (grade III n = 3; grade IV n = 2). The radioactive sources utilized were 192Ir in 26 cases and 125I in 4. Twenty-eight patients underwent permanent implantation, the other two received temporary irradiation with removable after-loaded catheters. Target volume was less than 15 cm3 in 6 cases, between 16–60 cm3 in 17 and more than 60 cm3 in 7. Tumour dose at the periphery of the target volume was: 70–100 Gy in 19 and 100–130Gy in 9 of the cases treated with permanent implantation; the patients irradiated with removable implants received 40–60 Gy in 5–7 days. General follow-up ranged between 0.3 and 6.9 years (mean = 2.5 years). The results are analyzed with reference to the following aspects: 1) natural history of the disease; 2) modalities and goal of the treatment; 3) place of brachy therapy as sole treatment and combined with the other available therapeutical means.

The rationale of surgical treatment of partial epilepsy is based on a series of different criteria. One of them is the information given by the study of electrocerebral signals on the development of the epileptic process and, in particular, on the topographic location of the lesional-functional epileptogenic complex (see Rossi et al. 1974, for an extensive review on the subject). Actually, there are patients in whom such a location can be defined only on the basis of the analysis of brain electrical activity which therefore becomes a factor of paramount importance for a reliable surgical indication. The use of depth electrodes—or stereoelectroencephalography (Bancaud et al. 1965)—is of substantial help in this connection. The experience accumulated in the last twenty years has brought a large convergence of opinion on the general principles, or tactical considerations, which are the basis of an stereoelectroencephalographic exploration of an epileptic patient regarded as a possible candidate for surgical treatment (Bancaud et al. 1965 and 1973; Talairach et al. 1974; Crandall 1973; Walter 1973; Rossi 1973; Rossi et al. 1974). However, in our opinion, a particular point deserves further discussion, namely the importance of the duration of the stereoelectroencephalographic exploration in order to obtain sufficient and reliable information. Our personal experience indicates that, in most cases, such a goal can be reached only, or can be greatly facilitated by utilizing prolonged and repeated recording, requiring “chronically” implanted intracerebral electrodes. The following findings illustrate our views.

A stereotactic device is described which, without modifying the main characteristics of the Talairach’s stereotactic apparatus, increases its flexibility in orthogonal approaches. This accessory, which replaces the double-grid system, permits any orthogonal access on the X and Y coordinates and insertion of any type of electrode, catheter or probe, without the constraints of the double grid holes. Its use in different stereotactic operations (brain tumor biopsy or curietherapy, implantation of intracerebral depth electrodes for stereo-EEG recording) proved its wide working capability and great reliability.

Stereotactic biopsies were carried out in an attempt to define the grading of 99 neuroectodermal tumors with respect to their modalities of growth and their degree of malignancy. Valuable data has been obtained in all explored tumors. The reliability of the information provided by stereotactic biopsy depends on the careful planning of the procedure by exploring different parts of the tumor as well as of the surrounding brain tissue.