Biomedical subjects

O O Betti

Publications and source records attributed to O O Betti.

15 recordsLinked to original sources

PubMed1992

Stereotactic approach to intracranial lesions.

The diagnostic and therapeutic approach to intracranial lesions must be different considering the different possibilities offered by the various methods. The diagnostic reliability and safety of stereotactic biopsy are often indispensable in order to optimize the subsequent therapy. The results obtained in selected pathologies allow us to propose the stereotactic approach to treat: -various kind of cysts by aspiration and/or Beta endocavitary radiation therapy; -blood or abscessual collections that can be aspirated in a similar way; -arterio venous malformations or tumours by radiosurgery; -tumours by brachicurietherapy or by computer assisted stereotactic surgery. We present some cases treated at the C.H.S.A. of Paris and at the C.H.R.U. of Grenoble utilizing Talairach methodology.

Adolescent↗

PubMed1992

[Radiosurgical treatment of minor intracranial arteriovenous malformations by using a linear accelerator].

This study deals with 43 patients with cerebral arteriovenous malformations (AVMs) of a maximum of 20 mm in diameter. All of them were radiosurgically treated with a linear accelerator in stereotatic conditions (UMIC). The delivered doses vary from 20 gys to 50 gys. Thirty-seven were controlled angiographically and 35 of them showed the disappearence of the AVM. Different parameters can modify the results: delivered dose, the size and shape of the lesion, target-volume, peripheral lesion isodosis (75%), location, underestimation of the size or dose. These results show that small lesions are best to treat than larger ones, particularly because their volume enables us to encompass them more easily. The uniformity of this series is related to the homogenous size of the treated AVMs, thus avoiding the discussion of global, unclear, results.

Adolescent↗

PubMed1991

Radiosurgery with a linear accelerator. Methodological aspects.

Based on the concepts of Leksell and on recommendations of different Swedish physicists on the use of linear accelerator for radiosurgical use, we developed a new methodology coupling the Talairach stereotactic system with a commercial linac. Anatomical facts encouraged us to use coronal angles of irradiation employing the angular displacement of the linac above the horizontal plane. Different coronal planes are obtained by rotation of the stereotactic frame. The center of the irradiated target coincides with the irradiation and rotation center of the linear accelerator. Multiple targets can be irradiated in the same session. We use as recommended a secondary collimator in heavy alloy. Special software was prepared after different dosimetric controls. The use of a PC allows us to employ 1-6 targets and different collimators to displace the isocenters in order to obtain geometrical isodose modification, and to change the value of each irradiation arc or portions of each arc in some minutes. Simple or sophisticated neurosurgical strategies can be applied in the treatment of frequently irregular shape and volume AVMs.

Brain↗

PubMed1989

Differential diagnosis between tumoural and non-tumoural intracranial lesions in children: a stereotactic approach.

The rational management of intracranial lesions should be based on the exact definition of the nature of the lesions and, when it is possible, on their spatial definition. Since External Radiotherapy (ERT) and cytostatic therapy are not free of undue effects, especially in children, such treatments should be used only when a "sure" diagnosis is obtained. The aim of this paper is to study the results allowed by the Talairach's stereotactic methodology in children. During the period January 1979-December 1986, 704 stereotactic procedures including serial biopsies, were performed at the S. Anne Hospital in Paris. One hundred forty-eight procedures (21%) concerned 134 children (78 M; 56 F) aged from 2 to 16 years. The interval between the occurrence of the first clinical symptoms and the stereotactic procedures varied between 1 and 180 months (m: 24 m). Fifty-two (40%) had previous therapeutic procedures without precise diagnosis. The lesions were hemispheric in 46 (34%) and deep seated in 88 (66%). The serial stereotactic biopsies proved the existence of a non-tumoural lesion in 20 children (14.9%): (cryptic vascular malformation: 5, cortical dysplasia: 3, haematoma: 3, ischaemia: 1, granuloma: 1, degenerative pathology: 2, cicatrix: 2, post-ERT alterations: 1, arachnoidal cyst: 2). Four were in the brain stem. In 3 patients (2%), a precise diagnosis was not obtained. The CT scan characteristics of the 20 non-tumoural lesions did not permit to establish a precise differential diagnosis. The therapeutic management was adapted to the diagnosis, avoiding potentially dangerous procedures in the 20 non-tumoural lesions.

Adolescent↗

PubMed1989

Stereotactic radiosurgery with the linear accelerator: treatment of arteriovenous malformations.

An original stereotactic radiosurgical approach coupling a) Talairach's stereotactic methodology, b) a specially devised mechanical system, and c) a linear accelerator is detailed. The authors present their preliminary results on 66 patients with nonsurgical intracranial arteriovenous malformations. The doses delivered for treatment varied from 20 to 70 Gy. Doses of no more than 40 Gy were used in 80% of patients. An angiographic study was performed when the computed tomographic scan controls showed relevant modifications of the lesion volume. Total obliteration was obtained in 27 of the 41 patients (65.8%) who were followed up for at least 24 months. The percentage of the cured patients is significantly higher when a) the entire malformation is included in the 75% isodose (96%) and b) the maximum diameter of the lesion is less than 12 mm (81%). Two patients died of rebleeding at 18 and 29 months after treatment.

Adolescent↗

PubMed1987