[Evolution of the use of the portal imaging device: prospective study over three years]. / Evolution des concepts d'utilisation de l'imagerie électronique: étude prospective sur trois périodes.

PURPOSE: To describe the evolution of the use of the electronic portal imaging device (EPID) over three periods. MATERIAL AND METHODS: From 1990, as part of the quality assurance research programs, the radiotherapy department of the G.-F. Leclerc Centre of Dijon used EPID systems in a prospective fashion. During the first of the three periods (PER 1:1990-1993), the study consisted of analysis criteria determination, software efficiency improvement and a selection of patients who could benefit from the method. Eight hundred and forty-five images of 40 patients were analysed qualitatively and quantitatively. Two verifications per week were planned, and the action level for correction was 10 mm. Head and neck images were also displayed in 'cinema' presentation for internal movements analysis. From 1994 to 1995 (PER 2), off-line procedure (OLP) based upon early correction of the systematic error and the rules calculated from our previous experience were tested for checking the brain, head and neck (LOC 1: 396 images) and many of the pelvic irradiations (LOC 2: 260 images). A double-exposure procedure and/or movie loop presentation was reserved for other patients. During the last period (PER 3: 1996-1997), the OLP procedure was routinely performed in 54 patients (images: 321 LOC 1, 680 LOC 2). RESULTS: LOC 1: deviations of < 3 mm increased from 75.5% during PER 1 to 81% during PER 2 to 83% during PER3. Conversely, deviations of 3-5 mm dropped from 19.5 to 13%, while deviations of more than 5 mm remained stable, around 5%. The actual standard error of the mean deviation observed was 2 mm. LOC 2: deviations of < 5 mm were observed in 81% of the cases during PER 1 and in 91% during PER 3 (89.5% in PER 2). These good results led to a decrease in deviation of 5 to 7 mm (11 to 6%) and also to a significant drop in deviations of more than 7 mm, 8 to 3% respectively. The actual precision obtained was 2.5 mm +/- 3 mm SD. CONCLUSIONS: The OLP based upon the early correction of the systematic error led to a significant increase of setup accuracy of patients irradiated for the brain, head and neck, and especially for pelvic lesions.

[Assessment of the use of electronic portal imaging]. / Bilan de l'utilisation de l'imagerie électronique.

Improvement in the accuracy of the positioning of the patient during external irradiation is one of the most important issues of the last decades, due to the detrimental impact of the misplacements on treatment outcome. Since 1990, the evolution of the technologic environment has led to a full integration of the portal imaging devices into linac technology. It offers a real on-line verification tool for "high-dose, high-accuracy" treatments. This overview based upon data from the literature describes the different types of imaging devices, the strategies of use and the results obtained. It also considers the use of imaging devices as an in vivo dosimeter.

Polysomnography scoring for sleep apnea. Use of a sampling method.

The all-night polysomnogram is used to assess the severity of sleep apnea by the quantitative analysis of a number of respiratory and sleep parameters. Because precise scoring of these parameters is a time-consuming process, we studied the effect of scoring varying percentages of polysomnograms on the accuracy of estimating sleep apnea severity. Twenty adult all-night polysomnograms with apnea-hypopnea (AH) indexes ranging from 1.0 to 67.8 were scored in the following manner: every 30-s epoch (100% scoring), every other epoch (50% scoring), every fourth epoch (25% scoring), every sixth epoch (16.7% scoring), every eighth epoch (12.5% scoring), and every tenth epoch (10% scoring). Each method was then compared with 100% scoring. For each parameter we established criteria for classifying studies as having a mild, moderate, or severe degree of abnormality. The number of studies correctly categorized for the following parameters was: (1) AH index, 20/20 for 50 and 25% scoring, 19/20 for 16.7 and 10% scoring, and 18/20 for 12.5% scoring; (2) AH time, 20/20 for 50, 25, and 16.7% scoring, 17/20 for 12.5% scoring, and 18/20 for 10% scoring; (3) mean AH duration, 20/20 for 50, 25, and 12.5% scoring, 18/20 for 16.7% scoring, and 15/20 for 10% scoring; (4) mean event percent O2 saturation, 20/20 for 50 and 25% scoring, 18/20 for 16.7 and 12.5% scoring, and 17/20 for 10% scoring; (5) longest AH, 19/20 for 50% scoring, 18/20 for 25% scoring, and 15/20 or less for 16.7, 12.5, and 10% scoring; (6) lowest percent O2 saturation, 19/20 for 50% scoring, 17/20 for 25% scoring, and 15/20 or less for 16.7, 12.5, and 10% scoring.(ABSTRACT TRUNCATED AT 250 WORDS)

Pasteurella multocida lung abscess. A case report and review of the literature.

A 65-year-old man was seen with an asymptomatic solitary pulmonary nodule of at least five months' duration. Culture of a percutaneous needle aspirate yielded Pasteurella multocida. Surgical resection of the lesion showed an acute and chronic lung abscess histologically, and culture again yielded P multocida. The potential for this rare human respiratory tract pathogen to cause indolent, necrotizing parenchymal pulmonary infection in an asymptomatic patient is thus documented. The roentgenographic appearance of the lesion mimicked a primary carcinoma.

[The dose response relations in geotropic and phototropic stimulation: Comparison of mono-with dicotyledonous plants]. / Die Dosis-Wirkungsrelationen bei geotroper und phototroper Reizung: Vergleich von Mono- mit Dicotyledonen.

The increase in the geotropic curvatures of Avena coleoptiles and Lens epicotyls is linear and proportional to the time of stimulation. With low stimulation the sensitivities of both objects are equal; with longer stimulation the curvature of Avena coleoptiles is somewhat greater.To increased phototropic irradiance Lens epicotyls react with a first and a second positive curvature. Between the two ranges of curvature (from about 10,000 up to 1,000,000 lx · sec) they are phototropically insensitive; negative curvatures never occur. The same reaction is shown by 12 other dicotyledonous plants (Brassica napus, Brassica oleracea subsp. capitata, Brassica oleracea subsp. bullata, Lepidium sativum, Vicia villosa, Sinapis alba, Cucumis sativus, Linum usitatissimum, Helianthus annuus, Agrostemma githago, Raphanus sativus, Convolvulus tricolor) and by 3 other monocotyledonous plants (Hordeum distichon, Secale cereale, Triticum aestivum). In the first positive reaction the phototropic sensitivities of Avena coleoptiles and Lens epicotyls are equal, in the second positive reaction Avena coleoptiles are more sensitive. For Lens epicotyls (for Avena coleoptiles, too) the reciprocity law is valid in the first positive reaction, but not in the second positive reaction.