Air-Coupled Ultrasonic Probe Integrity Test Using a Focused Transducer with Similar Frequency and Limited Aperture for Contrast Enhancement

Air-coupled ultrasonic probes require a special design approach and handling due to the significant mismatch to the air. Outer matching layers have to be soft so can be easily damaged and excitation voltages might cause the degradation of electrodes or bonding between the layers. Integrity inspection is desired during design, manufacturing, and exploitation. Spatial distribution of a transduction efficiency over piezoelement surface is proposed as a convenient means for the air-coupled probe integrity inspection. Focused transducer of similar center frequency is used to scan the surface of the inspected probe. However, such approach creates a challenge, i.e., area of the scanning beam is much smaller than the total receiving area of the inspected probe, therefore, contrast and imaging resolution are significantly degraded. Masking aperture made from cardboard and felt, placed at the focal point was proposed as solution. Far-range sidelobes were suppressed down to the noise floor (−50 dB) and the near-range sidelobes were reduced down to −17 dB. The proposed modification allows to use a similar frequency focused transducer. Probe integrity inspection can be carried out at significantly enhanced contrast and lateral resolution. Natural and artificial defects can be detected by the use of the proposed method.

Age- and Gender-Specific Risk of Thyroid Cancer in Patients With Familial Adenomatous Polyposis

Context: The cribriform-morula variant of papillary thyroid carcinoma (CMV-PTC) is a rare variant of PTC and is associated with familial adenomatous polyposis (FAP). However, the incidence and the nature of CMV-PTC among FAP patients have not been well characterized. Objective: The aim of this study was to determine the incidence and characteristics of thyroid cancer screened by neck ultrasonography for FAP patients. Design, Patients, and Intervention: A total of 129 FAP patients were included in this study. Neck ultrasonography was performed using a 12.0-MHz transducer probe. Germline APC gene mutation was examined for by the protein truncation test or DNA sequencing methods. Results: Twenty-one patients (16.3%) had solid nodules, and 24 patients (18.6%) had benign cystic nodules. In total, PTC was found in 11 patients (16% of the women and 0% of the men), 8 of which were CMV-PTC and the rest were classical PTC. In 17 female patients with thyroid nodules, CMV-PTC occurred in 8 of 9 patients who were 35 years age or younger but in none of the 8 patients who were older than 35 (P = .0004 by Fisher’s exact test). The APC germline mutations in 8 patients with CMV-PTC were present at the 5′ side of the profuse type of FAP region (codons 1249–1330). Conclusions: The prevalence of CMV-PTC in FAP patients was higher than previously reported and this type of tumor was found preferentially in younger (under age 35) female patients with FAP in this cohort.

The Influence of Sensitivity Field of Dual Transducer Probes on Accuracy of Discontinuity Sizing and Evaluation in Terms of Testing of Forgings According to EN 10228-3

The article presents results of research on the impact of sensitivity distribution of double transducer probes, which are often used in non-destructive ultrasonic testing of components such as forgings. Distribution of sensitivity measured in two orientations, parallel and perpendicular to the plane of separation of a double transducer probe has been tested and analyzed. A significant influence of orientation of a probe on echo envelope of an artificial point discontinuity has been studied. It has revealed great differences in length and shape of an echo envelope, depending on a type of probe and orientation of a probe separation plane to the moving direction. Eventually, the analysis of practical consequences of dual transducer probes usage for characterization of a type, dimensioning and evaluation of internal discontinuities, in accordance to the methodology specified in EN 10228, has been conducted.

Flexible Linear Array with Curvature Sensor

A 1-MHz compact and flexible linear array transducer probe with a curvature sensor was developed to be shaped directly in human body curvatures. This transducer will be used for human bone imaging, in an attempt to substitute x-ray radiography. The curvature sensor, based on strain gauge construction, is embedded in the same flexible polymer matrix of the transducer. This sensor measures the curvature of the unknown surface and determinates the actual position of the emitter/receiver ceramics during scanning, in order to use the focal time-delay law. This avoids problems related to beam distortions and enhances the sensitivity of the transducer. A phantom simulating cortical human bone was used to test the transducer. As a result, images of cortical bone phantom were obtained.