Multi-array high-intensity focused ultrasound transducer

Multi-array HIFU piezo ceramic ultrasound transducers can also be divided into two types, one is pure multi-array form, and the other is multi-phase phased array focusing. A pure multi-array element generally places a plurality of piezoelectric ceramic sheets in the concave spherical surface of several tens of centimeters in a certain regularity, and the center of focusing of all the piezoelectric ceramic sheets coincides at the center of the spherical center, thereby forming a focal region. The difficulty is mainly in the installation, the position of each focusing should be completely coincident, and the electrical characteristics of each piezoelecric wafer and the stability of multiple power amplifiers are required to be completely consistent. A typical multi-array transducer has a piezoelectric wafer with a diameter of about 30 mm, which is arranged on the three different latitudes of the concave spherical surface, the number of which is 5, 1 1 , 16 respectively; at the highest latitude, four laser emitters are installed to mark the range of the ultrasound field; the center of the concave spherical surface has a circular hole for the B-ultrasonic monitoring probe to pass, and many achievements have been made in the design and development of the ultrasonic transducer. It is a multi focusing of ultrasonic transducer, a multi-element HIFU piezo for therary device, and they have been developed. 

Eight pieces piezoelectric ceramic is fixed on the transducer shell, and is positioned by a positioning taper hole and an adjusting screw. It is symmetrically arranged on a conical ring. The focusing of each high focus piezo ceramic is superposed on the axis of the conical ring by adjusting the screw to form a high-intensity ultrasonic wave. In the focal region, the ultrasonic transducer is symmetrically arranged on the conical surface by a plurality of concave spherical self-focusing transducers of different focal lengths, and the components are respectively focused on respective focal points, and distributed on a common axis to form a long focal length according to a certain regularity, it is short focal length and other focal points, thus reducing treatment time.

The meridian split-type high focus ultrasound piezo transducer is different from the former two. The piezoelectric ceramic is evenly divided into spherical caps with a meridian, and the inner surface has a radius of curvature equal to the radius of curvature of the outer surface of the matching layer, and is closely spliced into a complete continuous focusing radiating surface. Each piezoelectric ceramic has the same radius of curvature and shape, and the matching piezo layer is opening in the middle, and the installation position of B-ultrasound. The concave spherical piezoelectric ceramic is divided into a plurality of individual array along the meridional direction, and the acoustic matching layer is still a large-aperture concave spherical shell having a uniform thickness, and resonates at the working frequency together with all the piezoelectric wafers, thereby realizing focusing ultrasound field.

The focusing of the Hifu piezoelectric crystal is designed to be within the range of 50mm to 120mm. Since the treating tumor is generally inside the body, a large focal length is required. Such a large opening angle will inevitably lead to a large probe size. , the structural design of the whole machine requires consideration. The advantage is that it can reduce the damage to the human body on the ultrasonic conduction path as much as possible. At the same time, it is ensured that there is sufficient intensity and rising temperature in the focusing position, which significantly reduces the patient's pain. It is worth pointing out that many units have declared that they can achieve painless treatment while is promoting high-intensity focused ultrasound tumor treatment. The investigation found that it is in the process of Hifu piezoelectric sensor used for ultrasound therapy, it is generally necessary to perform different degrees of anesthesia on the patient. Otherwise, the patient will have obvious pain. The ultrasound waves pass through the skin surface of the human body. Generally speaking, there are different degrees of burn. High-intensity focused ultrasound transducers with full phased array can be focused .