Arbai Yusuf

A novel sensor design for breast cancer scanner based on Electrical Capacitance Volume Tomography (ECVT)

In this study, we proposed a novel sensor for real time 3D imaging of cancerous mass within human breast using the capacitance measurement method, namely Electrical Capacitance Volume Tomography developed earlier. The sensor works based on the fact that cancerous mass has much higher relative permittivity as compared with normal breast tissue. The electrical capacitance volume tomography (ECVT) imaging technique is capable of generating volumetric image of permittivity distribution of the breast in real time. The 3D sensor constitutes a half-sphere of sensing region to capture the whole permittivity image of the breast. The sensor consists of 24 electrodes with combined triangular and rectangular shapes. Simulated phantoms as well as actual phantom of human breast constituting paraffin as normal human breast tissue and rubber as breast cancer tissue have been used to test the reliability of the sensor system to evaluate the performance of the ECVT technique for breast cancer imaging. The reconstructed images using simulated objects as well as actual measurement using the actual phantom have shown accurate permittivity distributions. The results obtained showed a great feasibility of the 4D tomography imaging as an alternative for a robust and high speed nonradiation technique for breast cancer screening.

Hardware implementation of linear back-projection algorithm for capacitance tomography

This paper presents method to implement Linear Back Projection (LBP) algorithm in Field Programmable Gate Arrays (FPGA). Top-down approach has been adopted for the design of the hardware of LBP algorithm. The FPGA used is Xilinx Spartan 3A and the language used to design the hardware is VHSIC Hardware Description Language (VHDL). The final design is able to reconstruct a 32×32 pixel image from 8-electrode Electrical Capacitance Tomography (ECT) with speed of 23809 slice images per second and the image is shown on LCD. It could be further extended to form quasi 3D image with 32 slices at rate 744 frame-per-second.

Single signal conditioning multi electrode for ECVT data acquisition system

Data acquisition system with single signal conditioning for multi-electrode on electrical capacitance volume tomography (ECVT) was described. ECVT is a method in 3D process imaging based on electrical capacitance. The ECVT hardware is employed to measure capacitance signal from 32 electrodes as sensory module. In this investigation, one signal conditioning was used for all electrodes hence hardware construction is simplified and power consumption is relatively low. In order to achieve that, switch configuration which could form analog multiplexer with small resistance and capacitance is required. Each electrode needs 4 analog switches, so that for 32 electrodes 128 analog switches are needed. The electrode is selectable according to desired function as excitation or detection. Experiment result has shown that this ECVT system is able to accomplish capacitance measurement with resolution 0.42 fF.

Analysis of single excitation signal for high speed ECVT data acquisition system

This research investigates single excitation signal applied on ECVT (electrical capacitance volume tomography) data acquisition system (DAS). ECVT is one of tomography processes based on capacitance measurement. Excitation signals being used in the system are square and sine waves. Single wave excitation signal was injected into pair electrodes which would produce one capacitance measurement. This method lessen the time required to acquire data thus fasten the data acquisition speed. For 16 channels, 138 frame per second could be achieved. The proposed method does not decrease accuracy and sensitivity of capacitance measurement.

Development of two axis solar tracking using five photodiodes

Utilization solar panels to generate electricity were increased all over the world including Indonesia. Generally, solar panels mounted on permanent structure which the angle of sunlight direction are fixed. This installation method will reduce the efficiency of electrical energy generated by solar panels due the angle of sun direction changes every time. There are needs equipment that used to steer solar panels toward the sun, namely solar tracking. In this study, we proposed development a prototype of two-axis solar tracking using five photodiodes. Overall, solar tracking system consists of two DC motors, five photodiodes, microcontroller system, and mechanical structure. DC motors are used to driving toward azimuth and elevation, photodiode act as sun-sensor functioned to measure the angle of sunlight direction, microcontroller system functioned to process data and give signal to DC motors. The five photodiodes usage are intended to reduce the cost purchasing of sun-sensor which relatively expensive on the market. Solar tracking prototype has been tested using artificial light with an intensity is closer to the sunlight. Experiment result has shown that this solar tracking is able work very well and can follow the sun movement.

Design of capacitance measurement circuit for data acquisition system ECVT

In this research, we proposed a capacitance measurement circuit Electrical Capacitance Volume Tomography (ECVT) to perform three-dimensional image visualization. The ECVT system is consists of three main parts i.e. sensor, data acquisition system, and computer. Data acquisition system is composed of capacitance measurement circuit and microcontroller to measure an unknown capacitance inside the sensor, collect data and send it to the computer. Further, these data is used to reconstruct 3D image. The design of the circuit used a sine wave 14.6 Vp-p and 2.5 MHz of frequency injected to the electrode pair to measure an unknown capacitance inside the sensor. An experiment is performed using simulated phantom using sensor having the form of a half-sphere with combined triangular and rectangular shapes. The system is able to measure a capacitance value as low as four femto-Farads with 0.34% margin error.

Development of the data acquisition system for the 32-channel electrical capacitance volume tomography

Electrical Capacitance Volume Tomography (ECVT) is one of three-dimensional image visualization method using capacitance effect. This paper describes a data acquisition system for 32-channel electrical capacitance volume tomography based on CMOS switch technology and charge-discharge system. Test results show the data acquisition system capable to measure of a novel capacitance with 0.21 fF to 0.42 fF resolution. Data rates of this system are four frames per second for 32 channels.

Brain tumor detection using electrical capacitance volume tomography (ECVT)

In this study, for the first time, we have used the ECVT technique, developed earlier for real-time and volumetric imaging of brain activity, to detect the presence of brain tumor. The ECVT sensor system measures the capacitance of electrical signals of the brain on the cortex, and generates a volumetric map of the brain activity on the cortex and inside the brain through a tomography image reconstruction algorithm based on a Neural-Network Multi-criteria Optimization Image Reconstruction Technique (NN-MOIRT). The ECVT is able to detect brain tumors through an examination of the brain functional abnormalities, as the tumors block the propagation of neuro-signals and cause abnormalities in the brain activity image. The ECVT sensor design has been optimized for the detection of the brain tumors in different sensitivity regions of the brain. Case studies have been carried out to five volunteers suffering from different brain tumors including ependymoma, oligodendroglioma, cranio-pharyngioma, germinoma pineal, and cerebellopontine angle tumors. Comparisons with their respective CT and MRI results have also been performed. The study has shown a great feasibility of the 4D imaging technique as a complementary alternative for a high speed non-radiation technique for brain cancer detection and functional imaging.