C. Morel

GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy

GATE (Geant4 Application for Emission Tomography) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. Dedicated to the modelling of planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET) acquisitions, this platform is widely used to assist PET and SPECT research. A recent extension of this platform, released by the OpenGATE collaboration as GATE V6, now also enables modelling of x-ray computed tomography and radiation therapy experiments. This paper presents an overview of the main additions and improvements implemented in GATE since the publication of the initial GATE paper (Jan et al 2004 Phys. Med. Biol. 49 4543-61). This includes new models available in GATE to simulate optical and hadronic processes, novelties in modelling tracer, organ or detector motion, new options for speeding up GATE simulations, examples illustrating the use of GATE V6 in radiotherapy applications and CT simulations, and preliminary results regarding the validation of GATE V6 for radiation therapy applications. Upon completion of extensive validation studies, GATE is expected to become a valuable tool for simulations involving both radiotherapy and imaging.

Estudo comparativo entre aneurismas rotos tratados por cirurgia e por via endovascular

The management of intracranial aneurysms has truly evolved after the introduction of the endovascular treatment. In this paper we compare patients that were operated or embolized for intracranial aneurysms. Between 1995 and 1999, 78 grade I to III ruptured aneurysms were treated in our service: 52 patients were operated, 21 were embolized and 5 were submitted to combinated endovascular and surgical treatment. In the surgical group, clinical outcome was very good in 80.8% of cases with 5% of mortality with 96.2% of total exclusion of the aneurysm. In the endovascular group, 95% of cases the clinical outcome was very good with only 42.8% of total exclusion of the aneurysm. By the endovascular method for treatment of aneurysms, we can obtain a good clinical outcome but a poor radiological outcome and sometimes need a complementary surgical procedure to treat residual aneurysm.

Neurocitomas do sistema nervoso central: análise clínico-patológica de três casos

Central nervous system neurocytoma is a rare benign tumor of neuronal origin. Because of some clinical and radiological findings CNS neurocytomas were confused with other intraventricular lesions (ependymomas, choroid plexus papilloma, oligodendrogliomas, subependymal astrocytomas). Pathological diagnosis improved with immunohistochemical and electron microscopic studies. We present three cases of intraventricular neurocytomas confirmed by immunohistochemical studies. According to the literature clinical signs, radiological features, surgical and pathological findings are discussed.