An Investigation of Microwave Tomography Technique to Detect Brain Tumour Through Cross-Section Imaging at Frequency 0.5 GHz to 1.5 GHz

The growing significance of cancerous tissue including brain tumour requires a fast and efficient technology detection. The most current technologies being applied for brain imaging system are Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI). Whilst these two detection applications are very well established, both systems are expensive, time and space consuming, and raise safety issues to patients due to the radiation and strong magnetic effects. This research aims to assess the feasibility and potential performance of microwave tomography (MWT) for brain imaging with a particular focus on brain tumour detection. The study was conducted using Finite Element Model software, COMSOL Multiphysics to develop a 2D modelling of an antenna array and measure the scattered electric field by solving forward problem. MATLAB software will be used as an inverse problem solver to reconstruct 2D images of the tumour by using Linear Back Projection (LBP) algorithm.

Localización de emuladores de carcinomas en modelos experimentales de mama mediante tomografía de impedancia eléctrica basada en linear back projection

Introducción: La medición y caracterización de la impedancia eléctrica de los tejidos biológicos permite distinguir entre tejidos sanos y patológicos. El uso de técnicas como la tomografía de impedancia eléctrica es muy utilizada en pruebas clínicas a través de diversas aplicaciones. En este trabajo se emplea el método Linear Back Proyection (LBP) para reconstruir imágenes a partir de la medición de impedancia eléctrica con el objetivo de localizar emuladores de carcinoma insertados en modelos de agar-agar con forma de mama femenina.Método: Un arreglo anillar de ocho electrodos fue empleado para realizar mediciones de impedancia en siete modelos de agar-agar con forma de mama femenina. Se diseñó y simuló en el software COMSOL un corte transversal de una mama femenina sana (sin emuladores) que representa el plano de medición del arreglo anillar de electrodos. Se calcularon los mapas de sensibilidad de cada par de electrodos a lo largo de la medición de impedancia utilizando los datos de la distribución de conductividad del modelo simulado. Finalmente, la reconstrucción de la imagen de tomografía eléctrica para cada modelo se obtuvo aplicando el algoritmo LBP a los valores de impedancia eléctrica medidos en el arreglo anillar de electrodos.Resultados: Se calcularon los mapas de sensibilidad a partir de las mediciones de impedancia obtenidas de cada modelo experimental considerado. Como resultado se generó una matriz de sensibilidad que caracteriza la distribución de los potenciales eléctricos dentro del plano de medición simulado en COMSOL. La zona de localización obtenida fue correcta para todos los modelos experimentales con emuladores de carcinomas insertados fuera del centro del arreglo anillar de electrodos.Discusión o Conclusión: De acuerdo con los resultados obtenidos del proyecto descrito, la metodología propuesta permite la generación de imágenes para localizar emuladores de carcinoma con diámetros aproximados de 1 cm, ello a través de un enfoque no iterativo. Por lo anterior, la localización no requiere una alta complejidad computacional. La localización de un emulador de carcinoma insertado en la zona central del modelo de mama femenina no se obtuvo correctamente debido a la baja sensibilidad de la configuración anillar de los electrodos en dicha zona.

On the Use of a Rotatable ECT Sensor to Investigate Dense Phase Flow: A Feasibility Study

This paper presents the feasibility study of dynamic flow measurements using the concept of a rotatable electrical capacitance tomography (ECT) sensor. The experiment considered horizontal flow in a pneumatic conveying flow loop in the case of dense phase flow. Slugs and settled layers were imaged and a comparison was made between no rotation or rotation of the sensor for two image reconstruction schemas: linear back projection (LBP) and non-linear iterative back projection. Data were evaluated both qualitatively and quantitatively by estimating the solids concentration level for different hue levels.

Anomaly Detection Using Electric Impedance Tomography Based on Real and Imaginary Images

This research offers a method for separating the components of tissue impedance, namely resistance and capacitive reactance. Two objects that have similar impedance or low contrast can be improved through separating the real and imaginary images. This method requires an Electrical Impedance Tomography (EIT) device. EIT can obtain potential data and the phase angle between the current and the potential measured. In the future, the device is very suitable for imaging organs in the thorax and abdomen that have the same impedance but different resistance and capacitive reactance. This device consists of programmable generators, Voltage Controlled Current Source (VCCS), mulptiplexer-demultiplexer potential meters, and phase meters. Data collecting was done by employing neighboring, while reconstruction was used the linear back-projection method from two different data frequencies, namely 10 kHz and 100 kHz. Phantom used in this experiment consists of distillated water and a carrot as an anomaly. Potential and phase data from the device is reconstructed to produce impedance, real, and imaginary images. Image analysis is performed by comparing the three images to the phantom. The experimental results show that the device is reliable.

Simulasi Rekonstruksi Citra Pada Sensor Brain ECVT (Electrical Capacitance Volume Tomography) dengan Metode ILBP (Iterative Linear Back Projection)

<p>The purpose of this study is to simulate the sensor 32-channel Brain ECVT image reconstruction using ILBP (Iterative Linear Back Projection) methods. ECVT is a dynamic volume imaging technique that utilizes non-linear difference of electric field distribution to determine the distribution of permittivity in the sensing area. ECVT has measured the capacitance of data as a result of changes in the permittivity distribution between the electrode pairs. ECVT device consists of three main parts: helmet-shaped sensors, DAS (Data Acquisition System), PC for display and image reconstruction process. Simulation of sensor design using COMSOL Multiphysics 3.5 software, while the process of image reconstruction and analysis of the results using Matlab software 2009a. The principle of ECVT includes two stages of data collection capacitance of electrodes (forward problem) and image reconstruction from the measured capacitance (inverse problem). In the study, the simulation of image reconstruction was done by varying the object position, the number of objects and charge density of the object. From the simulation results showed that the reconstructed image with ILBP method is influenced by several parameters: the object's position in the sensor,charge density value of the object, an alpha value and the number of iterations was selected.</p>

Towards 3D-Electrical Capacitance Tomography for Interface Detection

The application of three-dimensional electrical capacitance tomography (3D-ECT) for the in situ monitoring of a hard boundary or interface has been investigated using imaged phantoms that simulate real-life processes. A cylinder-in-tube phantom manufactured from polyethylene (PE), a low di-electric and non-conductive material, was imaged using the linear back projection (LBP) algorithm with the larger tube immersed at varying intervals to test the ability of the technique to image interfaces axially through the sensor. The interface between PE and air is clearly imaged and correlates to the known tube penetration within the sensor. The cylinder phantom is imaged in the centre of the sensor; however, the reduction in measurement density towards the centre of the ECT sensor results in reduced accuracy. A thresholding method, previously applied to binary systems to improve the imaged accuracy of a hard boundary between two separate phases, has been applied to the 3D-ECT tomograms that represent the PE phantom. This approach has been shown to improve the accuracy of the acquired image of a cylinder of air within a non-conductive PE tube.