[Radiography of scoliosis: comparative dosimetry between conventional technique and digital fluorography]. / Radiographie des scolioses: dosimétrie comparée entre la technique conventionnelle et la fluorographie numérique.

OBJECTIVE: Compare the irradiation delivered in conventional radiography and digital radiography by image intensifier during a scoliosis workup. PATIENTS AND METHODS: Our prospective randomized study included 105 patients, all of whom were identified according to sociodemographic parameters as well as criteria evaluating the quality of the full front spinal x-ray at PA incidence. The entry dose at the scapula and the exit dose in interorbital, thyroid, mammary, and hypogastric projection was measured by thermoluminescent dosimeters. RESULTS: The results of 71 girls and 28 boys, aged a mean 13.8 years with a mean weight of 47 kg were analyzed. At equal image quality, the entry dose was not significantly different between the two techniques; the mean exit dose reduction was 64% during digital acquisition. This reduction involved the interorbital (162%), mammary (43%), and thyroid (309%) regions. However, this system is more irradiating in the hypogastric region (34%). CONCLUSION: The dosimetric evaluation of the different imaging techniques used to explore the entirety of the spine should be part of radiologists' quality standard used to document their work and their choices.

Radiation dose to the lenses in CT of the paranasal sinuses.

The radiation dose to the lens during CT of the paranasal sinuses was measured in 20 patients. In 10 patients, a "standard" technique with axial and coronal sections was used. In the remaining 10 patients, overlapping axial sections for bidimensional reconstruction were obtained. Radiation dose was measured using thermoluminescent dosimeters. The mean dose was 22 mGy in patients who underwent "standard" CT and 42 mGy in those who underwent CT with overlapping sections. Dose was dependent on the total number of slices and of transorbital axial sections. Coronal sections did not statistically increase the radiation dose to the lenses. Although these doses were significantly below the critical dose for cataracts, CT with overlapping sections gives a considerably higher radiation dose. We recommend the bidimensional reconstruction technique only for selected cases (e.g. preoperative assessment of the roof of the ethmoid sinuses or in patients who can or should not maintain the hyperextended position required for coronal views.

[Modification of the radiosensitivity of cultured "Vero" cells by cumene hydroperoxide]. / Modification de la radiosensibilité de cellules "Vero" en cultures par l'hydroperoxyde de Cumène.

Cumene-hydroperoxide is a radical reaction promoter. Vero cells monolayers treated with this compound were irradiated with gamma-rays and their radiosensitization was compared with that of irradiated, non-treated control cells. Cumene-hydroperoxide treated cells showed a paradoxal radioresistance. We propose a possible buffer-like effect of cumene-hydroperoxide to explain these results.