Variation in dielectric properties due to pathological changes in human liver

Abstract

Dielectric properties of freshly excised human liver tissues (in vitro) with several pathological conditions including cancer were obtained in frequency range 100 MHz-5 GHz. Differences in dielectric behavior of normal and pathological tissues at microwave frequencies are discussed based on histological information for each tissue. Data presented are useful for many medical applications, in particular nanosecond pulsed electroporation techniques. Knowledge of dielectric properties is vital for mathematical calculations of local electric field distribution inside electroporated tissues and can be used to optimize the process of electroporation for treatment planning procedures.

Minimum information for dielectric measurements of biological tissues (MINDER): A framework for repeatable and reusable data

“…At the same time, dielectric data analysis is conducted. The dielectric data may be fitted to numerical models for use in simulations and ease in reporting . Common models include the Debye and the Cole‐Cole models .…”

“…The dielectric data may be fitted to numerical models for use in simulations and ease in reporting . Common models include the Debye and the Cole‐Cole models . The model parameters are optimised to match the data using techniques such as the least‐squares method or the genetic algorithm .…”

“…However, clinical confounders have been relatively uninvestigated to date and may introduce a significant level of additional uncertainty into the dielectric data . While not an exhaustive list, clinical confounders that have been identified in the literature are: the tissue source; animal age and weight; the use of anaesthesia/drugs; physiological parameters (blood flow, blood oxygenation, blood pressure, heart rate, respiration rate); in‐vivo vs ex‐vivo measurements; time since death/excision; the sample temperature and cooling or warming of the sample; sample dehydration and blood loss; contamination or artificial drying of surface; quality of probe‐sample contact; probe‐sample pressure; the sensing depth and sample size; tissue sample heterogeneity; the technique for marking measurement location on the tissue sample; sample or data exclusion criteria; pathologist methodology; and the histological analysis technique . Confounders can also be introduced when the dielectric data is reported in the form of models, due to the choice of model type; the number of poles used in the model; the fitting algorithm used to obtain the model parameters; and the accuracy of the fitting technique …”

Membrane permeabilization of mammalian cells using bursts of high magnetic field pulses

“…However, these applications require direct contact between the applicator, electrodes and the biological sample. Therefore, despite many applications, the methodology has considerable limitations such as the dependence of PEF distribution on the dielectric properties of the sample (Corovic et al, 2013; Peyman et al, 2015; Campana et al, 2016a; Liu et al, 2016), presence of electrochemical reactions in the electrode-electrolyte or tissue interfaces (Pataro et al, 2015) and the possibility of electrical breakdown between the electrodes (Guenther et al, 2015; Rubinsky et al, 2016). …”

Variation in the dielectric properties of freshly excised colorectal cancerous tissues at different tumor stages

“…Lazebnik et al [] reported that the difference in dielectric properties between malignant and normal adipose‐dominated breast tissues was considerable, with up to a 10:1 difference, whereas the difference between malignant and normal glandular/fibroconnective tissues in the breast was no greater than approximately 10%. In addition, dielectric characteristics may change significantly under various pathological states [Peyman et al, ] at different locations [Surowiec et al, ; Swarup et al, ], particularly between different stages of tumor development [Swarup et al, ]. One previous study by Swarup et al [] revealed an obvious increasing trend of dielectric properties with growing tumor staging in fibrosarcoma tissue.…”