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)Purpose To validate the predictive power for determining breast cancer risk of an automated breast density measurement system with full-fi eld digital mammography (FFDM). Materials and methods Two hundred cancers and 200 controls were imaged with FFDM. Density was measured separately on MLO and CC images using an integral automated volumetric breast density measurement system (Hologic, Quantra). For each cancer, the contralateral mammogram was used. Each cancer was matched to a control case by date of birth, age at examination and laterality of mammogram used for density determination. Breast density (percentage of fi broglandular tissue) was analyzed by Quantra. Data were analyzed by conditional logistic regression to determine the eff ect on breast cancer risk. Results The percentage of breast density ranged from 6% to 63%. Density declined signifi cantly with age (P <0.001). Overall, there was no signifi cant association of density with risk of breast cancer (P = 0.4). There was a suggestive increase in risk with dense volume higher than 35% (OR = 1.80, 95% CI = 0.96 to 3.39, P = 0.07). There was signifi cant heterogeneity by age in the eff ect of density on risk (P = 0.04). In women aged <50, density was signifi cantly associated with increased risk (P = 0.02), with odds ratios of 6.06, 3.98 and 10.59 for density volumes of 15 to 24%, 25 to 34% and ≥35% respectively, relative to those with <15%. In women aged ≥50 years there was no association of density with risk (P = 0.5). Conclusions Quantra automated volumetric breast density measurement is strongly associated with breast cancer risk in women aged under 50, but not in women aged ≥50 years or over. O2Ultrasound elastography as an adjuvant to conventional ultrasound in the preoperative assessment of axillary lymph nodes in suspected breast cancer: a pilot study K Taylor Introduction NICE guidelines recommend conventional ultrasound (CU) of the axilla as preliminary staging in patients with breast cancer. However, up to one-third of nodes showing normal morphology are metastatic on surgical histology [1]. Ultrasound elastography (UE) uses received radiofrequency data to produce an elastogram depicting tissue stiff ness. UE has been researched in the breast but there are no published data regarding UE of the axilla. Methods Fifty women attending the breast unit as symptomatic GP referrals with breast lesions sonographically suspicious of breast cancer underwent UE of the axilla simultaneously with routine CU examination. Elastograms were visually scored, strain measurements calculated and nodal perimeter and area measurements recorded. UE was compared with CU with histology as the reference standard. Results Twenty-nine nodes were histologically normal, 21 were metastatic. Normal nodes were indistinguishable from surrounding tissue on UE. Using cut-off points for biopsy selected for the study, sensitivity was 90% for UE visual scoring, 100% for strain scoring and 76% for CU. Specifi cities were 86%, 48% and 78% respectively. ROC analysis yielded AUC values ...

A new class of compact microstrip bandpass filters, the stepped impedance resonators of which are located close together at a gap of 0.1-0.2 mm, is described. Basic two and three element sections of microstrip filters, which are designed around stepped impedance impedance resonators used to implement tiny selective devices with overall sizes and characteristics comparable to those of microwave ceramic filters, are proposed. It is justified that the mentioned filters can be equipped with closely neighboring metallic shields whose heights are equal to the substrate thickness. As a consequence, these filters turn out to be thin ner. The frequency responses of experimental microstrip filters operating at frequencies of 1.75-2 GHz and manufactured on the 1 mm thick substrates with the permittivity ε r = 100 have been analyzed. The three pole microstrip filter with a shield (its operating frequency is 1.96 GHz, and sizes are 5 × 5 × 1.5 mm) has been simulated. It is demonstrated that new microstrip filters can be competitive with low sized ceramic filters in certain applications.

This paper presents the results of studies of the kinetics of the conduction current in the pulsed regime of high-resistance KTP crystals with electrical resistivity 1 5 × 10 10 Ω cm, grown from solutions in a phosphate melt by a modified Czochralski method. It is established that, when the electric field is switched on, there is slow growth of the conduction-current pulse, whose leading edge is about 5.2 ms wide. In the electrooptic modulators of Nd:YAG lasers controlled by a driver with pulsed bias, the bias-pulse width usually lies in the range 50-300 μs. The conduction current through high-resistance KTP crystals does not exceed 100 nA in such a regime, and, as shown by our experiments on lifetime, there are virtually no limits on the use of modulators based on KTP crystals associated with their electrochromic degradation.