Spectroscopic thermoacoustic imaging of water and fat composition

Abstract

During clinical studies, thermoacoustic imaging (TAI) failed to reliably identify malignant breast tissue. To increase detection capability, we propose spectroscopic TAI to differentiate samples based on the slope of their dielectric absorption. Phantoms composed of different ratios of water and fat were imaged using excitation frequencies between 2.7 and 3.1 GHz. The frequency-dependent slope of the TA signal was highly correlated with that of its absorption coefficient (R2 = 0.98 and p < 0.01), indicating spectroscopic TAI can distinguish materials based on their intrinsic dielectric properties. This approach potentially enhances cancer detection due to the increased water content of many tumors.

An Integrated Simulation Approach and Experimental Research on Microwave Induced Thermo-Acoustic Tomography System

“…Thermo-acoustic pressure waves, induced via local heat deposition by microwave energy absorption, can be described via the thermo-acoustic wave equation [16,17], i.e.,…”

“…Thus, the thermal confinement condition [14] is satisfied. Under thermal stress confinement, the heating function can be rewritten in a form with product separated contribution of the spatial H( r) and temporal δ(t ) parts [16,17].…”

“…Some experimental MITAT systems have been developed and been reported [12,13,[15][16][17]. In order to validate the performance of the integrated simulation approach, we have developed a MITAT system.…”

“…Two-and three-dimensional (2-D and 3-D) imaging of breast tissue phantoms or real breast tissue specimens have been investigated [14][15][16][17]. In the study of MITAT techniques, a fast and accurate simulation approach is necessary to help designing and optimizing system.…”

System Development of Microwave Induced Thermo-Acoustic Tomography and Experiments on Breast Tumor

“…Neglecting magnetic losses, Equation (4) indicates that the intrinsic contrast in thermo-acoustic tomography is dominated by electric losses in the imaged sample. In early breast cancer detection, the physical parameters (β, C V , v s ) have low variation in soft tissue and can usually be neglected for contrast [22]. Thus, the objects with high conductivity have higher energy absorption than tissue with lower conductivity.…”