Non-Invasive Microwave-Based Imaging System for Early Detection of Breast Tumours

Abstract

This work introduces a microwave-based system able to detect tumours in breast phantoms in a non-invasive way. The data acquisition system is composed of a hardware system which involves high-frequency components (antennas, switches and cables), a microcontroller, a vector network analyser used as measurement instrument and a computer devoted to the control and automation of the operation of the system. Concerning the software system, the computer runs a Python script which is in charge of mastering and automatising all the required stages for the data acquisition, from initialisation of the hardware system to performing and saving the measurements. We also report on the design of the high-performance broadband antenna used to carry out the measurements, as well as on the algorithm employed to build the final medical images, based on an adapted version of the so-called Improved Delay-and-Sum (IDAS) algorithm improved by a Hamming window filter and averaging preprocessing. The calibration and start-up of the system are also described. The experimental validation includes the use of different tumour models with different dielectric properties inside the breast phantom. The results show promising tumour detection capabilities, even when there is low dielectric contrast between the tumoural and healthy tissues, as is the usual case for dense breasts in young women.

Microwave Imaging System Based on Signal Analysis in a Planar Environment for Detection of Abdominal Aortic Aneurysms

“…The radiating power in the antennas, considering the RF system losses and the radiation efficiency of the antenna, is higher than –7.8 dBm. It should be noted that this emission power is sufficiently low so that the proposed system can be deemed harmless to the users [ 17 , 20 ].…”

“…This is a non-ionizing technology that utilizes a very low emission power—more than 100 times lower than the power emitted by current mobile phones and roughly 100 times lower than the limits imposed by the SAR (Specific Absorption Rate) regulations, which all the electromagnetic emissions in biological contexts must comply with [ 15 , 16 , 17 ]—thus ensuring the full safety of these systems and the consequent possibility of using them repeatedly [ 18 ]. Currently, we can find several MWI devices and prototypes for different medical applications, including breast cancer detection [ 19 , 20 , 21 ], dynamic image building for cardiovascular systems [ 22 ], brain tumor classification [ 23 ], fast image building after cerebrovascular accident [ 24 , 25 ], or brain-shift detection during brain tumor surgery [ 18 ].…”

Multifrequency Microwave Radiometry for Characterizing the Internal Temperature of Biological Tissues

“…The measured voltages for each radiometer are listed in Table 7. Table 8 lists the temperatures calculated using the equations from ( 16)- (18), and the values are compared with an external measurement using an infrared thermometer pointing at the rear face of the load. A great consistency between the provided values by the radiometer and external measurements is observed.…”

“…The system is basically composed of a probe antenna followed by a sensitive receiver, as shown in Figure 1. Recently, there has been growing interest in MWR, and significant results were demonstrated within the biomedical field, focusing on anomalies in breast, brain, carotid artery, back pain or diabetic foot, among others [17,18]. Furthermore, MWR can complement superficial temperature measurements provided by infrared sensors, in cases in which a high risk of the appearance of skin ulcers is present, such as diabetic foot patients [19,20].…”

Low-Cost Direct-Writing of Silver-Based Ink for Planar Microwave Circuits up to 10 GHz

“…In particular, printed antennas are widely used as part of smart sensing systems [20] and PE techniques have further extended their use to numerous applications [21]- [26]. More recently, effort is being invested in the development of non-invasive medical diagnostic techniques based on microwave imaging systems, with printed antennas as the primary sensing elements [27], [28], which offer a cost-effective and promising medical imaging solution but currently present some challenges for use in clinical settings [29].…”