Impact of Electromagnetic Property Variations in Breast Tissue Liquid Phantoms and Models on the Performance of UWB Radiofrequency Tumor Detection Systems

Abstract

As in many medical device systems development, the design of radiofrequency breast tumor detection systems undergoes a test phase based on the use of liquid phantoms. It is well known the difficulty in obtaining phantoms that precisely model each tissue for each frequency of interest while keeping such properties for a long time. Despite the many available studies using such phantoms, limited information is available on a systematic analysis of the effect that the use of an imprecise phantom may have on the characterization of radiofrequency systems. This work presents the design and fabrication of ultra-wideband liquid breast and tumor phantoms. The main issue with this approach is that incorrect phantom properties, as well as an incorrect frequency response, lead to assessment errors. The current research focus is mainly focused on the model of the phantom, rather than its electromagnetic properties. Typically, the EM properties of breast phantoms are accurate only in a small frequency range, and these properties are frequency dependent. To address this issue, we validated a homogeneous breast phantom with good results in terms of dielectric permittivity (1.613% < error < 3.22%) and loss tangent (error < 33%) in the wide frequency range of [1–6] GHz. The proposed phantom retains its properties for a significant period of time, degrading only 6.78% in 2 h after fabrication while exposed to the environment. When it is stored in a container, only a small variation of ±1.7% was registered after 9 months.