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P Charnock

Publications and source records attributed to P Charnock.

2 recordsLinked to original sources

Evaluation and testing of computed radiography systems.

The implementation of film replacement digital radiographic imaging systems throughout Europe is now gathering momentum. Such systems create the foundations for totally digital departments of radiology, since radiographic examinations constitute the most prevalent modality. Although this type of development will lead to improvements in the delivery and management of radiological service, such widespread implementation of new technology must be carefully monitored. The implementation of effective QA tests on installation, at periodic intervals and as part of a routine programme will aid this process. This paper presents the results of commissioning tests undertaken on a number of computed radiography imaging systems provided by different manufacturers. The aim of these tests was not only to provide baseline performance measurements against which subsequent measurements can be compared but also to explore any differences in performance, which might exist between different units. Results of measurements will be presented for (1) monitor and laser printer set-up; (2) imaging plates, including sensitivity, consistency and uniformity; (3) resolution and contrast detectability; and (4) signal and noise performance. Results from the latter are analysed in relationship with both system and quantum noise components.

Computers↗

Unilateral ovariectomy during pregnancy in well-nourished and undernourished rats: effects on placenta and fetal body and brain growth.

The possibility that maternal unilateral ovariectomy, which is said to enhance fetal growth, might also ameliorate the harmful of undernutrition was investigated. Maternal undernutrition throughout pregnancy and unilateral ovariectomy on day 13 of pregnancy were investigated separately and in combination in primigravid rats with respect to male and female placental and fetal growth. Undernutrition increased the number of fetal resorptions in the 3rd week of pregnancy and depressed placental and fetal weights in both sexes, although there was some relative sparing of fetal brain weight. Unilateral ovariectomy of well-nourished mothers on day 13 of pregnancy caused significant increments in placental weight, and fetal body and brain weight in both sexes, but not in fetal length. None of these effects were observed in underfed mothers; that is, unilateral ovariectomy was ineffective in ameliorating the consequences for the fetus of maternal undernutrition. In none of the groups was there a significant relationship between fetal body weight and the number of fetuses, although in the undernourished litters significant negative correlations between fetal body weight and total number of placentae (normal and supernumerary) were found.

Animals↗