Applications of Microwaves in Medicine

Abstract

Advances and updates in medical applications utilizing microwave techniques and technologies are reviewed in this paper. The article aims to provide an overview of enablers for microwave medical applications and their recent progress. The emphasis focuses on the applications of microwaves, in the following order, for 1) signal and data communication for implants and wearables through the human body, 2) electromagnetic energy transfer through tissues, 3) noninvasive, remote or in situ physical and biochemical sensing, and 4) therapeutic purposes by changing tissue properties with controlled thermal effects. For signal and data communication and wireless power transfer, implant and wearable applications are discussed in the categories of pacemakers, endoscopic capsules, brain interfaces, intraocular, cardiac and intracranial pressure sensors, neurostimulators, endoluminal implants, artificial retina, smart lenses, and cochlear implants. For noninvasive sensing, remote vital sign radar, biological cell probing, magnetic resonance and microwave imaging, biochemical, blood glucose, hydration and biomarker sensing applications are introduced. For therapeutic uses, the developments of microwave ablation, balloon angioplasty, and hyperthermia applications are reviewed. The scopes of this article mainly concentrate on the research and development efforts in the past 20 years. Recent review articles on specific topics are cited with accomplishment highlights and trends deliberated. At the end of this article, a brief history of the IEEE Microwave Theory and Techniques Society (MTT-S) Biological Effects and Medical Applications committee and the contributions by its members to the promotion and advancement of microwave technologies in medical fields are chronicled.

Vivaldi Tapered Slot Antenna for Microwave Imaging in Medical Applications

“…To guarantee that the degree of electromagnetic field exposure is within acceptable limits, it is crucial to note that the SAR exposure levels must comply with safety norms and laws. The VTSA's SAR value, which was determined in this work at 0.326 W/kg, is within acceptable bounds and may be employed as a biological detector in an imaging system [4], [18].…”

“…The air anomaly has a much lower relative permittivity value than water, making it easier for the antenna to detect and produce a shift in the S-parameter values. This demonstrates the TSA design's effectiveness in detecting anomalies in the water phantom object [4], [18]. When comparing simulation results with real experiments in microwave imaging, it is common to observe slight differences between the two graphs.…”

Comparative analysis of energy transfer mechanisms for neural implants

“…Safety standards are also set by organizations like the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers (IEEE) ( SCENIHR, 2008 ) These entities aim to minimize bio-effects such as tissue heating by enforcing Specific Absorption Rate (SAR) limits which accounts for tissue electrical conductivity, electric field intensity, and tissue mass ( Chiao et al, 2023 ). The IEEE’s C95.1 Standard, for instance, limits the 10-g averaged SAR to 1.6 W/kg over a 6-min period.…”

A Tuned Microwave Resonant System for Subcutaneous Imaging

“…Frequent X-ray exposure may create additional risks. To increase screening accuracy, magnetic resonance imaging (MRI) has been used to provide a second modality of imaging to reduce the rate of false negatives [ 10 ], especially for those at high risk. The instrument costs and operation requirements are higher than those of mammography.…”