Angiogenesis-promoting effect of LIPUS on hADSCs and HUVECs cultured on collagen/hyaluronan scaffolds.

Angiogenesis refers to blood vessel formation through endothelial cell migration and proliferation. Angiogenesis is crucial and beneficial for wound healing and tissue regeneration. In the current study, we prepared porous collagen and collagen/hyaluronan (Col/HA) scaffolds composed of collagen (7 mg/mL) and hyaluronan (HA) (0.

Alternative approach of cell encapsulation by Volvox spheres.

Volvox sphere is a bio-mimicking concept of a biomaterial structure design able to encapsulate chemicals, drugs and/or cells. The aim of this study was to prepare Volvox spheres encapsulating AML12 liver cells and mesenchymal stem cells (MSCs) via a high voltage electrostatic field system. The results demonstrated that AML12 liver cells and MSCs could be successfully encapsulated into the inner spheres and the outer sphere of the Volvox spheres.

Temperature feedback based heating strategy for ultrasound thermal surgery.

Phased array transducer has the ability to generate multiple-focus pattern by adjusting the driving signal of individual element of the array. For the treatment of large target volume, several multiple-focus pattern could be used by using temporal switching technique among these power patterns. Typically, to obtain a uniform thermal dose, properly adjust the power level within the target volume is important.

Zero-crossing tracking technique for noninvasive ultrasonic temperature estimation.

Objective: The purpose of this study was to investigate the feasibility of a zero-crossing tracking (ZCT) technique for temperature estimation using ultrasound images.

Methods: The backscattered ultrasound radio frequency (RF) echo from a heated region experiences time shifts, which have been identified as causing a gross effect on sound speed changes and thermal expansion. The ZCT technique tracks the shifts in the zero-crossing instants between preheated and postheated A-lines to estimate the echo shifts caused by local temperature changes.

Instantaneous frequency-based ultrasonic temperature estimation during focused ultrasound thermal therapy.

Focused ultrasound thermal therapy relies on temperature monitoring for treatment guidance and assurance of targeting and dose control. One potential approach is to monitor temperature change through ultrasonic-backscattered signal processing. The current approach involves the detection of echo time-shifts based on cross-correlation processing from segmented radiofrequency (RF) data.

Split-focused ultrasound transducer with multidirectional heating for breast tumor thermal surgery.

This study investigated the feasibility of using a split-focused ultrasound transducer to perform thermal surgery on breast tumors, based on a multidirectional heating scheme. The transducer is a square section of a sphere with a radius of 10 cm. The transducer was tilted such that its acoustic beam was 45 degrees relative to the rib surface, and its focal zone was arranged by a shift of 6 mm away from the center of the planning target volume.

Investigation of a cylindrical ultrasound phased-array with multiple-focus scanning for breast tumor thermal therapy.

The purpose of this study is to investigate the feasibility of a cylindrical ultrasound phased-array with multiple-focus scanning strategy to produce a uniform heating for breast thermal therapy. In this study, a breast is surround by a 1-MHz cylindrical ultrasound phased-array consists of 200 elements with a radius of 10 cm and a height of 2 cm. To prevent overheating in the normal tissue, a scanning region of 1 cmt x 1 cm was selected as a single heating unit.

A novel strategy to increase heating efficiency in a split-focus ultrasound phased array.

Focus splitting using sector-based phased arrays increases the necrosed volume in a single sonication and reduces the total treatment time in the treatment of large tumors. However, split-focus sonication results in a lower energy density and worse focal-beam distortion, which limits its usefulness in practical treatments. Here, we propose a new heating strategy involving consecutive strongly focused and split-focus sonications to improve the heating efficiency.

Thermal therapy for breast tumors by using a cylindrical ultrasound phased array with multifocus pattern scanning: a preliminary numerical study.

The purpose of this study is to investigate the feasibility of using a 1 MHz cylindrical ultrasound phased array with multifocus pattern scanning to produce uniform heating for breast tumor thermal therapy. The breast was submerged in water and surrounded by the cylindrical ultrasound phased array. A multifocus pattern was generated and electrically scanned by the phased array to enlarge the treatment lesion in single heating.

Contrast-agent-enhanced ultrasound thermal ablation.

The small thermal lesions induced when using high-intensity focused ultrasound (HIFU) to ablate tumors results in long treatment duration. In this study, the effect of using ultrasound contrast agent (UCA, Definity) to enhance the ultrasound (US) thermal effects and, thus to enlarge the lesion size, was studied in transparent tissue phantoms insonified by 1.85-MHz US with acoustical powers of 28.

Investigation of a scanned cylindrical ultrasound system for breast hyperthermia.

This paper investigates the feasibility of a scanned cylindrical ultrasound system for producing uniform heating from the central to the superficial portions of the breast or localized heating within the breast at a specific location. The proposed system consists of plane ultrasound transducer(s) mounted on a scanned cylindrical support. The breast was immersed in water and surrounded by this system during the treatment.

One-dimensional phased array with mechanical motion for conformal ultrasound hyperthermia.

This paper investigates the feasibility of conformal heating for external ultrasound hyperthermia by using a phased array transducer with mechanical motion. In this system, a one-dimensional phased array is arranged on a shaft and moves along the shaft, while dynamically focusing on the planning target volume (PTV) with numerous focal spots. To prevent overheating in the intervening tissue between the skin and the PTV, the shaft and the phased array are rotated together to enlarge the acoustical window.