Ultrasonic Mammography with Circular Transducer Array

Abstract

Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection methods have been developed in the set-up of multi-element flat arrays with miniature transducers, where one of the array acts as a transmitter and the other one is a receiver.In the paper, a new method of the projection imaging using a 1024-element circular ultrasonic transducer array is presented. It allows the choice of a projection scanning plane for any angle around a studied object submerged in water. Fast acquisition of measurement data is achieved as a result of parallel switching of opposite transmitting and receiving transducers in the circular array and vertical movement of the array. The algorithm equalizing the length of measurement rays and the distances between them was elaborated for the reconstruction of projection images.Projection research results of breast phantom obtained by means of the elaborated measurement setup and compared with mammography simulations (acquired through overlapping of X-ray tomographic images) show that ultrasonic projection method presented in this paper (so-called ultrasonic mammography) can be applied to the woman's breast and be used as a diagnosis for an early detection of cancerous lesions. It can, most of all, be used as an alternative or complementary method to standard mammography, which is harmful because of ionizing radiation and invasive due to the mechanical compression of tissue.

Scattering by Circular Voids With Rigid Boundary: Direct and Inverse Problems for Open and Close Domains

“…In tomography problems, we often deal with many sensors emitting and receiving signals closely located to the external boundary. For example, Diffuse Optical Tomography or Radio Tomography could be mentioned [5][6][7].…”

“…3). Formally, the mathematical description would be almost identical as for Diffuse Optical Tomography [6][7][8][9], but the physical meaning of the state function, material coefficient and their units are different.…”

“…The reconstruction of the object (geometry only, without acoustical properties of the material) requires an accurate numerical model [4,6]. Moreover, it allows us to solve the inverse scattering problem, i.e., determine the parameters of the scatterer based on measurements of the incident and scattered fields taken on the external circular boundary.…”

“…Based on the Forward Problem, Dedicated iterative methods make it possible to formulate the inverse problems and solve the tomography tasks for acoustic [3,4,6]. The advantages of the acoustic or ultrasound approach for imaging, particularly in medicine, are obvious and do not demand further explanations.…”

On Precision Acoustic Wave Calculation in a Frequency Domain

“…(3) very often is treated as the Monopole Source which models a point source that radiates sound isotropically. An example of the acoustic source in 2D space might be a cross section of a cylinder with a small radius which alternately expands and contracts [4].…”