Reduced tube voltage for pediatric contrast material-enhanced CT reduces radiation dose and maintains image contrast. Image noise increases, but the effect is minimal in smaller phantoms. An additional reduction in tube current further reduces radiation dose.

An x-ray fluorescence system with a synchrotron radiation source was used to quantify the levels of iron, copper and zinc in breast tissue specimens. Healthy tissue and breast carcinomas were investigated as an aid to understanding the mechanisms of breast cancer and as a possible complementary diagnostic tool. Eighty samples were measured in total. Twenty samples were matched pairs, i.e. 20 tumour samples with 20 corresponding healthy tissue specimens taken at a distance from the tumour. The remaining 40 samples consisted of 20 excised tumours and 20 healthy specimens from breast reduction surgeries. The levels of the elements of interest were quantified via calibration models constructed using the XRF response from standard solutions. The statistical analysis of the results indicates elevation of the levels of all three trace elements in the tumours. The effect is more prominent for copper and zinc while the contrast between healthy and diseased tissue is enhanced when comparing the independent specimens rather than the paired samples. Specifically, the ratio of mean tumour to mean healthy concentration for iron was 1.6 for the paired samples and 2.7 for the non-paired samples. The ratios describing copper content were 3.1 for paired and 3.6 for non-paired samples while for zinc they were 2.4 and 4.4 respectively.

No abstract

In vitro neutron activation analysis (NAA) was performed on malignant and adjacent normal tissue from 46 human female breast tumours. The objective was to investigate the chemical environment of the tissues within which microcalcifications develop and to develop a method for discrimination between malignant and normal breast tissue. The elements Al, Br, Ca, Cl, Co, Cs, Fe, K, Mn, Na, Rb and Zn were significantly higher in the cancer tissues (all p < 0.001; except for Co, p < 0.003, Wilcoxon signed-ranks test). In addition, a significant correlation (0.80, Spearman rank correlation) was found for Rb and Zn in tumour tissues. Present results are supported by the findings of others. The relevance of elevated concentrations of these elements in cancer breast tissue remains a matter of conjecture. Evidence suggests that there is a connection both with increased cellular activity and blood supply and the formation of microcalcifications in malignant breast tissues. This study suggests an association between the elemental composition of breast tissues and the formation of breast particles. That is, elevations of elemental concentration and clustered calcifications in breast are possibly related.

Regional variations in collagen arrangement show that the highly ordered layers of the articular cartilage are the most important elements in supporting high variable loads. In lesions changes occur in the deep tissue whilst the overlying cartilage appeared normal. We therefore suggest that the interface region is a key element in the early stages of the disease.