WCST performance and schizotypal features in the first-degree relatives of patients with schizophrenia.

Since the findings concerning the Wisconsin Card Sorting Test (WCST) performance of healthy first-degree relatives of patients with schizophrenia are equivocal, it still remains unclear whether the WCST may serve as a neuropsychological indicator of vulnerability to schizophrenia. The aim of this study was to evaluate whether the first-degree relatives' schizotypal features could account for these discrepancies. The subjects were 24 schizophrenic probands, 49 of their first-degree relatives and 41 normal controls.

Dose resolution in radiotherapy polymer gel dosimetry: effect of echo spacing in MRI pulse sequence.

In polymer gel dosimetry using magnetic resonance imaging, the uncertainty in absorbed dose is dependent on the experimental determination of T2. The concept of dose resolution (Dpdelta) of polymer gel dosimeters is developed and applied to the uncertainty in dose related to the uncertainty in T2 from a range of T4 encountered in polymer gel dosimetry. Dpdelta is defined as the minimal separation between two absorbed doses such that they may be distinguished with a given level of confidence, p.

[Executive and amnestic functions of a group of first-degree relatives of schizophrenic patients].

Several lines of evidence seem to indicate that some neurocognitive measures could be phenotypic markers of predisposition to schizophrenia. The aim of this study was to investigate 21 patients with schizophrenia, 51 of their first-degree relatives and 46 nonpsychiatric controls, with a series of tests known to be sensitive to prefrontal cortical damage--the Trail Making Test, part B (TMT B), the Wisconsin Card Sorting Test (WCST) and a verbal fluency test (VFT)- and/or sensitive to temporo-hippocampic dysfunctions: verbal and visual memory and verbal learning tests from the Wechsler Memory Scale-Revised (Wechsler, 1987). Since parents and siblings share on average 50% of their genes with the schizophrenic proband, firstly we predicted that the first-degree relatives' performance would be at an intermediate level between patients and control subjects and secondly, we expected that a higher proportion of relatives than of control subjects would be impaired.

Research software for radiotherapy gel dosimetry.

Gel dosimetry using magnetic resonance imaging is a technique which allows measurement of three-dimensional absorbed dose distributions in radiation therapy. This paper presents details of a software tool written specifically to provide facilities to perform image processing required in research and development of gel dosimetry. Collections of magnetic resonance images can be converted into either longitudinal or transverse nuclear magnetic resonance relaxation images.