A theoretical study on evaluating brain tumor changes in tumor treating fields therapy by impedance detection

TL;DR

This paper explores using impedance detection to monitor brain tumor changes during TTFields therapy, offering a potential real-time alternative to MRI.

Contribution

The study proposes and validates a novel method for real-time tumor monitoring using TTFields electrodes as impedance sensors.

Findings

Impedance amplitude changes can detect tumor size variations with resolution over 1mm.

Signal-to-Noise Ratio exceeds 40 dB at typical TTFields parameters.

Impedance detection could continuously assess TTFields treatment efficacy.

Abstract

TTFields is a novel FDA-approved technology utilized for treating glioblastoma multiforme (GBM) within the brain. Presently, the effectiveness of therapy is evaluated through MRI imaging at random two-month intervals. Electrical impedance is an important and effective parameter for reflecting changes in tissue properties. In TTFields treatment for brain tumors, electrodes attached to the scalp deliver electric field energy to the tumor region. We hypothesize that these electrodes can also serve as sensors to detect impedance changes caused by tumor alterations in real time, thus continuously assessing the effectiveness of the treatment. In this work, we propose and scrutinize this hypothesis by conducting an in silico study to confirm the potential feasibility of the proposed concept. Our results indicate that the impedance amplitude change measured between opposing TTFields electrode arrays utilizing voltage and frequency of 50 V and 200 kHz (typical TTFields treatment parameters), has enough resolution (> 1mm) and Signal-to-Noise Ratio (> 40 dB) to evaluate tumor size change in the head. The impedance detection technique may be a significant augmentation to TTFields cancer treatment, enabling the continuous evaluation of safety and efficacy throughout the procedure.

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