[Petrous bone approach for the surgery of petroclival meningiomas]. / La vía transpetrosa para el abordaje de meningiomas petroclivales.

Four patients, 3 woman and 1 man, with giant petroclival meningiomata are presented. In all cases the tumor size exceed 44 mm in its greater diametre. Main clinical symptoms were endocranial hypertension and cranial nerves deficit. A modified transcochlear approach in two stages was used. A total petrosectomy was performed, using the petrosygmoidal via for opening the dura. Transversus and sygmoid sinus were spared. Total removal was achieved in 2 cases, subtotal and partly in each of the other 2. No operative mortality occurred (hospital exitus) and neurologic morbility related to V-VI-VII and VIII cranial nerves and 1 hemyparesia was recorded. The AA. explain and comment the fundamentals of the followed procedure and compare, as well, the own outcomes with those reported by more classic alternatives. Finally, the conclusion is drawn out that retroclival meningiomata are conditions treatable, although always are difficulty approached and demand meticulous microsurgical techniques.

[Use of track detector for the measurement of urine plutonium]. / Utilisation d'un détecteur de traces pour la mesure du plutonium urinaire.

In case of internal exposition by inhalation of plutonium compounds, the faecal excretion is many times higher than in urine. In case of emergency, the faecal analysis is, of course, the best control. But in case of chronic exposure, the urine analysis are better tolerated by workers and easier for the laboratory organization. The results presented pertain to Plutonium 239: the chemical separation is quite conventional but a track detection is used for counting. It was first necessary to optimise both, the thickness of the screen placed between the radioactive source and the detector, and the chemical treatment for transforming the tracks into holes. Three minutes were required to count the perforations by moving the detector across a spark system. Due to detector background and efficiency, a 30 day exposure time is required to detect 0.2 mBq of Plutonium 239 (that's enough in relation to legal limits).

Radiotoxicological intercomparisons organised by the Commissariat à l'Energie Atomique group in France.

People working in French nuclear plants are monitored either by whole body counting or by the measurement of biological samples. The radiochemical and radiometric procedures used have to be periodically reviewed. A working group, including practising biologists from CEA, EDF and the Armed Forces Health Service, instituted comparisons of radiotoxicological test assessments. Since 1978, about 60 intercomparisons have been made. Currently 30 European laboratories are involved in these intercomparisons. This paper provides a brief history of the intercomparison exercises, describes the logistics of sample collection and preparation, and presents the results, showing the position of each laboratory in relation to the reference and median values. Diagrams produced by radiochemical analysis, relating to plutonium in urine and in faecal samples, and to tritium, strontium and enriched uranium in urine, are analysed.