To address the need for high-resolution imaging in lung nodule detection and overcome the limitations of the shallow imaging depth associated with high-frequency ultrasound and the complex structure of lung tissue, we successfully integrated 50 MHz ultrasound transducers with 18-gauge biopsy needles. Featuring a miniaturized size of 0.6 × 0.5 × 0.5 mm³, the 50 MHz micromachined 1-3 composite transducer was tested to perform mechanical scanning of a nodule within a lung-tissue-mimicking phantom in vitro. The high-frequency transducer demonstrated the ability to achieve imaging with an axial resolution of 30 μm for measuring nodule edges. Moreover, the integrated biopsy needle prototype exhibited high accuracy (1.74% discrepancy) in estimating nodule area compared to actual dimensions in vitro. These results underscore the promising potential of biopsy-needle-integrated transducers in enhancing the accuracy of endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNA) for clinical applications.

Functional electrical stimulation (FES) is a vital method in neurorehabilitation used to reanimate paralyzed muscles, enhance the size and strength of atrophied muscles, and reduce spasticity. FES often leads to increased muscle fatigue, necessitating careful monitoring of the patient’s response. Ultrasound (US) imaging has been utilized to provide valuable insights into FES-induced fatigue by assessing changes in muscle thickness, stiffness, and strain. Current commercial FES electrodes lack sufficient US transparency, hindering the observation of muscle activity beneath the skin where the electrodes are placed. US-compatible electrodes are essential for accurate imaging and optimal FES performance, especially given the spatial constraints of conventional US probes and the need to monitor muscle areas directly beneath the electrodes. This study introduces specially designed body-conforming US-compatible FES (US-FES) electrodes constructed with a silver nanowire/polydimethylsiloxane (AgNW/PDMS) composite. We compared the performance of our body-conforming US-FES electrode with a commercial hydrogel electrode. The findings revealed that our US-FES electrode exhibited comparable conductivity and performance to the commercial one. Furthermore, US compatibility was investigated through phantom and in vivo tests, showing significant compatibility even during FES, unlike the commercial electrode. The results indicated that US-FES electrodes hold significant promise for the real-time monitoring of muscle activity during FES in clinical rehabilitative applications.

Lung cancer is the leading cause of cancer death worldwide with estimated over 230,000 being diagnosed in USA annually. Due to the poor 5-year survival rate (18.6%) for lung cancer, it is vital for the early-stage lung cancer diagnosis and therapy with curative intervention, which can dramatically reduce the mortality. Ultrasound ablation has been reported as a promising technique taking the advantages of acoustic impedance differences between the nodule tissue and normal lung tissue and the ability to focus acoustic energy with ultrasound array for focused high power and precise focal zone control. Yet, endoscopic ultrasound transducers still face the challenge of insufficient power output due to dimension constraints. Thus, in this work, we developed a miniaturized, multidirectional ultrasound transducer with an overall dimension of 2.2 × 2.2 × 6.0 mm³ for fitting in modern bronchoscopy procedures to target peripheral pulmonary lesions. Meanwhile, with a two-layer stack design, the multi-directional transducer was more efficient in generating high power with a small form factor design that is capable of inducing temperature rise to over 65 °C in 3 min for tissue ablations. For the in-vitro test, a temperature sensitive color-changing material has been demonstrated for mimicking the nodule with surrounding inflated bovine lung tissues. The ablated lesion size was first estimated with a thermal camera and then demonstrated with the color variation area. With a lesion size of 7.3 × 4.2 × 3.1 mm³ in vitro at a depth of 4 mm, the potential of the device for lung nodule treatment was validated.

Biopsy procedures are essential for definitive cancer diagnosis but remain limited by the risk of accidental blood vessel puncture, which can lead to hemorrhage and procedural failure. Conventional imaging guidance often provides insufficient vascular contrast, making vessel avoidance during needle insertion challenging. A rotational oblique spectral ultrasound (ROSUS) imaging system was developed to improve vessel detection and needle guidance during biopsy procedures. The device integrates a high-frequency PMN-PT 1–3 composite transducer mounted at a 45° angle within the 18-gauge needle tip, enabling simultaneous forward- and side-looking capability. By combining synchronized rotational–axial scanning with multifrequency signal ratio (MFSR) processing, ROSUS achieved volumetric images with blood–tissue contrast ratio improvement over 1.2 dB compared to conventional B-mode signal processing while maintaining high spatial resolution of 85 µm and 424 µm in axial and lateral directions, respectively. These results demonstrate that frequency-domain spectral processing can improve vessel and tissue differentiation, offering an 18-gauge needle-integrated platform for safer and more accurate biopsy needle-based procedures.