Electrical properties of phantoms for mimicking breast tissue

Abstract

In order to test and calibrate an EIT (Electrical Impedance Tomography) system, many researchers rely on phantoms mimicking breast tissues. These phantoms are usually made of saline solutions, agar and/or vegetables, allowing the user to set the conductivity of the material by changing the salt concentration. Due to that fact that the dispersion behavior in the vicinity of megahertz is fundamental to detect carcinoma, this work aims to propose a phantom composed by a mixture of agar and gelatin (emulating the normal tissue) and a piece of carrot (emulating the carcinoma). It also investigates the frequency dependence from 1 to 10,000 kHz. The proposed phantom showed capability to mimic some absolute and relative electrical parameters used to detect cancer according to the literature. The differences in the impedance modulus were found to be more dispersive in the mimic carcinoma tissue type than the normal mimic one. It is simple to prepare, low cost, has similar electrical properties to the ones that have been used in the literature, better mechanical properties and longer life time. It can be concluded that gelatin-agar gel may have a high potential to be used as a breast tissue phantom.

Characterizing mechanical and medical imaging properties of polyvinyl chloride‐based tissue‐mimicking materials

“…Various phantoms are manufactured using polysaccharides, agar, agarose and gelatin . However, water evaporation and bacterial growth are the major limitations to the long‐term preservation of biopolymers, and phantoms constructed from these materials . Chemically synthesized polymers are more stable and durable than biopolymers, but they show a certain degree of deviation from human tissues due to the lack of water …”

Proposal of a Lab Bench for the Unobtrusive Monitoring of the Bladder Fullness with Bioimpedance Measurements

“…According to Kandadai et al [ 42 ], the electrical conductivity of the agar phantom can be adjusted by doping it with sodium chloride (NaCl). Hence, agarose based tissue substitutes have been widely used in the literature to mimic several organs (brain, thyroid gland, breast [ 35 ]), for many applications, such as ultrasound imaging. In addition to being non-expensive, agar is not hazardous and easy to prepare.…”

“…Few phantoms for electrical impedance have been reported. They reproduce head [ 32 , 33 ] breast [ 34 , 35 , 36 ] or thorax [ 37 ].…”

Fundamentals, Recent Advances, and Future Challenges in Bioimpedance Devices for Healthcare Applications

“…Advances in more accurate body models and in technology to provide increased stability and SNR will lead to an improvement in image resolution [26,373]. Many researchers use phantoms that mimic body tissues to calibrate and test EIT systems [374]. As the intracellular compartment can only be observed at high frequencies, EIT usually needs a high bandwidth that is affected by the parasitic capacitance of the cables and switches.…”