[Dosimetric validation of compensator for their use in clinical routine, in conformation radiotherapy]. / Validation dosimétrique des compensateurs physiques pour leur utilisation clinique en radiothérapie conformationnelle.

PURPOSE: The aim of this work was to establish the acquisition, calculation and 3D compensator manufacturing optimum parameters. This methodology is based on virtual simulation and 3D dosimetry. MATERIALS AND METHODS: The material used is a helicoidal CT (PQ 5000-Marconi), a virtual simulation system (AcQsim version 4-Marconi), a Treatment Planning System (Dosigray), a linear accelerator Saturne 43 (Varian, CGR), an automated milling system for compensator filters (Autimo 2.5 D-HEK), a water tank phantom (wellhofer) and an homogeneous phantom with simple patterns in order to simulate the obliquity surface of patient body. The compensator was composed by granulate tin because this material ensures a good profile modulation. The compensation plane has been calculated at 80% to dose profile. The compensator thickness profile has been calculated with different acquisition (slice thickness, pitch factor), calculation (attenuation coefficient, bixel) and fabrication parameters (drill diameter, specification of milling system). RESULTS: After this preliminary study, we have defined the optimum parameters for the compensator realization. We have observed that the slice thickness, bixel size and drill diameter are the parameters that mainly affect the profiles homogeneity. The choice of parameters with smaller dimensions S = 3 mm; B = 3 mm, F = 3 mm, improve the profiles homogeneity. Though, for manufacture times compatible with the clinical routine, the selected parameters are S = 5 mm, B = 6 mm and F = 6 mm. Compensator can be used for any type of Linac. However, one must pay attention on their realization and their positioning on the beam central axis.

An empirical approach to informed consent in ovarian cancer.

The study was designed to define and compare the professional and the reasonable-person standards for provision of information to ovarian cancer patients, and to determine if patient information priorities could be anticipated by surrogate patients. Physicians treating ovarian cancer patients, women treated for the disease, and well lay women imagining themselves to have the disease used a visual analog scale to judge the importance of 57 questions that they might want answered before treatment decisions are made. On the basis of median importance scores, all groups judged questions relating to life expectancy as most important. Overall, judgments of the patient groups agreed well with one another; doctor-patient agreement was significant but smaller than between-patient agreement. Predicting an individual's judgments from his/her group, however, was very poor for all groups. Life experience and demographic characteristics rarely improved our ability to predict an individual's judgments.

[Diagnostic value of the routine thoracic image]. / Zum diagnostischen Wert der routinemässigen Thoraxaufnahme.

A considerable part of the amount of diagnostic medical radiation exposure to the population in the industrial nations is due to chest x-rays. We correlated diagnostic gain and medical indication for the screening procedure in 1000 patients referred. In fact, in only 270 patients a specific indication was given, and in only 136 cases were there pathologic findings. Our results suggest a more restrictive policy in indicating the procedure. We give proposals for optimization.

A study of the association between Crohn's disease and psychiatric illness.

This study is an examination of the association between Crohn's disease and psychiatric illness using careful gastrointestinal evaluation, a structured psychiatric interview of known reliability and validity, and explicit diagnostic criteria for psychiatric illness. A proband sample of 50 subjects with Crohn's disease was obtained from a university clinic and a private clinic. Fifty control subjects with chronic medical illnesses obtained from the same two clinic sources were also examined. Compared with controls, a significantly greater number of the patients with Crohn's disease met criteria for some psychiatric disorder at some time in their lives, and a significantly greater number had a diagnosis of depression. A greater number of the probands reported obsessional or phobic symptoms, and the mean number of obsessional symptoms was higher in probands than in controls. We found no evidence of an interaction between psychiatric disorder and Crohn's disease. The significance of the discovered association for the treatment and natural history of Crohn's disease is discussed.

A double-blind comparison of alprazolam vs. imipramine and placebo in the treatment of major depressive disorder.

In a 6-week double-blind trial 129 outpatients with major depressive disorder received either alprazolam, imipramine or placebo. Dosage was adjustable from 0.5 mg alprazolam, 25 mg imipramine or two capsules placebo b.i.d. to 4.5 mg alprazolam, 225 mg imipramine or three capsules placebo t.i.d. Both active drugs were more effective than placebo according to all the rating scales used. Alprazolam and imipramine did not differ consistently except in the somatic symptom cluster on the Hamilton Anxiety Rating Scale. Mean final daily dosage was 2.7 mg alprazolam, 117.3 mg imipramine and 7.2 capsules placebo. Patients on alprazolam reported fewer side effects than patients on imipramine and approximately the same number as patients on placebo. Anticholinergic side effects were commonly associated with imipramine; drowsiness was the most frequent side effect with alprazolam.

A controlled study of the association between ulcerative colitis and psychiatric diagnoses.

Fifty consecutive patients with ulcerative colitis were personally examined to determine the lifetime prevalence of specific psychiatric diagnoses. A personality assessment and a tabulation of recently occurring stressful events were done. A matched control sample with chronic nongastrointestinal medical illnesses was evaluated in the same way. The two groups were compared so as to quantify the relative association and impact of psychiatric disorder in ulcerative colitis. We found no greater frequency of diagnosable psychiatric disorder in ulcerative colitis patients than in the control population. Those with ulcerative colitis and a psychiatric illness did not appear to have more serious gastrointestinal involvement, nor did severity of the ulcerative colitis predict more frequent or more serious psychiatric disorder. Personality profiles were similar in probands and controls, and there was no correlation between the frequency of potentially stressful life events within the six months prior to interview and severity of ulcerative colitis at the time of interview. We did find slightly higher levels of obsessional symptomatology in ulcerative colitis cases, but this association appeared to be weak and unrelated to the severity of the gastrointestinal disorder. Despite the fact that more than a quarter of the ulcerative colitis patients had some diagnosable psychiatric illness, the occurrence of psychiatric disorder was rarely documented in the medical charts.