D. Lefkopoulos

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Embolization was used to reduce the size of brain arteriovenous malformations (AVMs) prior to radiosurgical treatment in 125 patients who were poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at another institution. According to the Spetzler-Martin scale, the AVMs were Grade(More)
OBJECTIVE The aim of this study was to retrospectively analyze the reasons for the failure of radiosurgical treatment of cerebral arteriovenous malformations (AVMs). METHODS Seventeen cases of noncured AVMs were reviewed 3 years after radiosurgical treatment. Follow-up ranged from 33 to 54 months (mean, 44.3 mo). Lesion dimensions varied from 9 to 55 mm(More)
BACKGROUND AND PURPOSE Conformal radiation therapy techniques require the delineation of volumes of interest, a time-consuming and operator-dependent task. In this work, we aimed to evaluate the potential interest of an atlas-based automatic segmentation software (ABAS) of brain organs at risk (OAR), when used under our clinical conditions. MATERIALS AND(More)
BACKGROUND AND PURPOSE After a review of the main radiosurgical published series, to evaluate our own series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery alone or in combination with embolization or surgery. PATIENTS and method. From January 1984 to December 1998, 705 patients were treated by a multidisciplinary team(More)
BACKGROUND AND PURPOSE Accurate conformal radiotherapy treatment requires manual delineation of target volumes and organs at risk (OAR) that is both time-consuming and subject to large inter-user variability. One solution is atlas-based automatic segmentation (ABAS) where a priori information is used to delineate various organs of interest. The aim of the(More)
To stereotactically irradiate ellipsoidal inclined arteriovenous malformations (AVMs) with a single isocenter one can use an adjusted inclined irradiation space with a reduced angular range of arcs. If one uses the maximum available irradiation space it is necessary to weight some of the arcs in order to closely encompass the lesion. It has been found that(More)
Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose-response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childhood cancer and particularly the related(More)
BACKGROUND AND PURPOSE The purpose was to present the successive steps of dosimetric planning and the different means used to allow the choice of the best solution among several planning projects considering the anatomical and clinical features of arteriovenous malformation. Method. Four successive steps were: A study of these factors for 5 different(More)
We present a review of current technological progress enabling improvement in the quality of stereotactic irradiations: imaging fusion; individual adaptation of dosimetric planning to the shape of the target thanks to several collimation systems, spatial modulation of the beam with the use of multileaf microcollimators, beam intensity modulation,(More)
BACKGROUND AND PURPOSE Between 20 to 50% of cerebral arteriovenous malformations treated with radiosurgery (RS) fail to obliterate 2 to 5 years after irradiation. Patients are not protected against the risks leading to treatment. Two therapeutic options can be used to eradicate the persisting nidus: micro-surgery and a second irradiation. Our group has(More)