Dielectric properties of colon polyps, cancer, and normal mucosa: <i>Ex vivo</i> measurements from 0.5 to 20 GHz

Guardiola, M.; Buitrago, S.; Fernández‐Esparrach, Glòria; O'Callaghan, J.M.; Romeu, J.; Cuatrecasas, Míriam; Córdova, Henry; Ballester, Miguel Ángel González; Cámara, Óscar

doi:10.1002/mp.13016

Cited by 41 publications

(52 citation statements)

References 53 publications

(119 reference statements)

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“…Biological tissues feature inherent dielectric properties, which are often expressed in terms of permittivity and conductivity, based on the interaction of an external field with the electric dipole moment of the samples [Volkov and Prokhorov, ]. Over the last few decades, the open‐ended coaxial probe method [Athey et al, ; Bobowski and Johnson, ] has been explored as a means to measure the dielectric properties of the tissues [Gabriel et al, ; Li et al, , ; Guardiola et al, ; Mirbeik et al, ]. The results indicated that the dielectric properties of human cancer tissues and the corresponding normal tissues are often quite different.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries

Sun

Cai

et al. 2020

Bioelectromagnetics

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The dielectric properties of normal and tumor human tissues have been widely reported in recent years. However, the dielectric properties of intrathoracic lymph nodes (LNs) have not been reported. In this communication, we measured the dielectric properties (i.e., permittivity and conductivity) of ex vivo intrathoracic LNs obtained from lung cancer surgeries. Results show that the permittivity and conductivity of metastatic LNs are higher than those of normal LNs over the frequency range of 1 MHz-4 GHz. Statistically significant differences are observed at single specific frequencies (64, 128, 298, 433, and 915 MHz and 2.45 GHz). Our study provides the basic data to support future-related research and fills the research gap on the dielectric properties of LNs in the lungs. Bioelectromagnetics. 2020;41:148-155.

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Section: Introductionmentioning

confidence: 99%

Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries

Sun

Cai

et al. 2020

Bioelectromagnetics

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“…1. This design is widely used in [16] Not available yet a ADR (Adenoma Detection Rate) is most important indicator of quality in colonoscopy and measures the proportion of colonoscopies in which at least one adenoma is found. This increase is referenced to conventional colonoscopy.…”

Section: System Requirements and Challengesmentioning

confidence: 99%

“…Robustness is one of the main requirements for using a MI system in a clinical environment that is especially rich in electromagnetic interferences and noise, which can lead to errors in the measured data. For this application, the frequency range 5-8 GHz gives the highest contrast among healthy colon, different types of polyps and cancer [15,16]. Furthermore, realtime, computationally-efficient and accurate imaging algorithms are required.…”

Section: System Requirements and Challengesmentioning

confidence: 99%

“…To this aim, advanced computer vision techniques [13] and new imaging modalities exploiting other mechanisms of contrast, different from the optical one, should be investigated. Mads et al [14] proposed near infrared Raman spectroscopy and we recently investigated the applicability of microwave imaging (MI) [15,16]. Table I shows the main features of the different technologies being used to improve conventional colonoscopy.…”

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confidence: 99%

“…This scattering is then collected by the receiving antennas and transformed into images of the body's permittivity profile using MI algorithms. We recently demonstrated that the complex permittivity correlates with the degeneration grade of colon polyps [15,16]; the more similar to cancer, the higher the relative permittivity and conductivity. The maximum contrast between healthy mucosa and cancer was obtained between 5 and 8 GHz and was 30-100% for the relative permittivity and conductivity, respectively.…”

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confidence: 99%

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Design and Evaluation of an Antenna Applicator for a Microwave Colonoscopy System

Guardiola

Djafri

Challal

et al. 2019

IEEE Trans. Antennas Propagat.

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This paper presents a design of a compact antenna applicator for a microwave colonoscopy system. Although colonoscopy is the most effective method for colorectal cancer detection, it suffers from important visualization restrictions that limit its performance. We recently reported that the contrast between healthy mucosa and cancer was 30-100% for the relative permittivity and conductivity respectively at 8 GHz, and the complex permittivity increased proportionally to the degeneration rate of polyps (cancer precursors). The applicator is designed as a compact cylindrical array of eight antennas attached at the tip of a conventional colonoscope. The design presented here is a proofof-concept applicator composed by one transmitting and one receiving cavity backed U-shaped slot antenna elements fed by an L-shaped microstrip line. The antennas are low profile and present a high isolation at 8 GHz. The antenna performance is assessed with simulations and experimentally with a phantom composed by different liquids.

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Deep learning‐based reconstruction of in vivo pelvis conductivity with a 3D patch‐based convolutional neural network trained on simulated MR data

Gavazzi

Berg

Savenije

et al. 2020

Magnetic Resonance in Med

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Purpose To demonstrate that mapping pelvis conductivity at 3T with deep learning (DL) is feasible. Methods 210 dielectric pelvic models were generated based on CT scans of 42 cervical cancer patients. For all dielectric models, electromagnetic and MR simulations with realistic accuracy and precision were performed to obtain and transceive phase ( ϕ ± ). Simulated and ϕ ± served as input to a 3D patch‐based convolutional neural network, which was trained in a supervised fashion to retrieve the conductivity. The same network architecture was retrained using only ϕ ± in input. Both network configurations were tested on simulated MR data and their conductivity reconstruction accuracy and precision were assessed. Furthermore, both network configurations were used to reconstruct conductivity maps from a healthy volunteer and two cervical cancer patients. DL‐based conductivity was compared in vivo and in silico to Helmholtz‐based (H‐EPT) conductivity. Results Conductivity maps obtained from both network configurations were comparable. Accuracy was assessed by mean error (ME) with respect to ground truth conductivity. On average, ME < 0.1 Sm −1 for all tissues. Maximum MEs were 0.2 Sm −1 for muscle and tumour, and 0.4 Sm −1 for bladder. Precision was indicated with the difference between 90 th and 10 th conductivity percentiles, and was below 0.1 Sm −1 for fat, bone and muscle, 0.2 Sm −1 for tumour and 0.3 Sm −1 for bladder. In vivo, DL‐based conductivity had median values in agreement with H‐EPT values, but a higher precision. Conclusion Anatomically detailed, noise‐robust 3D conductivity maps with good sensitivity to tissue conductivity variations were reconstructed in the pelvis with DL.

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Dielectric properties of colon polyps, cancer, and normal mucosa: Ex vivo measurements from 0.5 to 20 GHz

Cited by 41 publications

References 53 publications

Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries

Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries

Design and Evaluation of an Antenna Applicator for a Microwave Colonoscopy System

Deep learning‐based reconstruction of in vivo pelvis conductivity with a 3D patch‐based convolutional neural network trained on simulated MR data

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