Conceiving THz Endometrial Ablation: Feasibility, Requirements and Technical Challenges

Abstract

Shallow-ablation of endometrial lining using microwaves has been traditionally indicated as a minimally invasive treatment option for dysfunctional uterine bleeding (DUB). Known as microwave endometrial ablation (MEA), relevant procedure is used as an alternative to hysterectomy considering its safety, simplicity and effectiveness. In lieu of the prevailing MEA techniques, it is attempted in this study to foresee the possibility of conceiving an alternative and a newer option on endometrial ablation using mm-wave/THz frequencies. Commensurate with this motivated impetus, objectively considered are merits and design issues of using electromagnetic (EM) spectrum of mm-wave/THz region toward optimal conversion of EM energy into a thermal ablative source so that, the basal layer of endometrium can be effectively destroyed in surgical contexts as necessary. Hence, the feasibility of designing appropriate TEA applicators for controlled and safe procedures so as to ablate just the unwanted tissues within a localized zone of energy field is addressed. Lastly, a quantitative analysis on the interaction of THz EM-energy versus the lossy dielectric characteristics of endometrial medium is indicated to model the underlying (THz-energy)-to-(thermal energy) transduction. Relevant prospects of conceiving TEA and the associated pros and cons are identified specific to the prospects of feasibility, requirement considerations and technical challenges.

Biomedical Applications of Terahertz Spectroscopy and Imaging

“…These findings indicate that THz radiation poses a slight potential health hazard. By contrast, a new endometrial ablation technique using THz irradiation instead of microwaves was proposed by converting the electromagnetic energy of the THz band into thermal energy [97]. Theoretical analyses showed the potential for clinical application, but technical challenges remain.…”

de Novo Radio Frequency Ablation Therapy: Application of Unexplored Electromagnetic Spectral Resources of mm-Wave/THz Band in Clinical Ablation Procedures – A Review

“…The procedure called endometrial ablation is intended to destroy the endometrium or the lining of the uterus with the goal of reducing the so-called DUB (Dysfunctional Uterine Bleeding) [16,23], also known as menorrhagia. It refers to incessant menstrual bleeding that is heavy in amount or duration and that occurs at regular intervals.…”

“…In short, while pursuing EM-based clinical ablation, it may be of interest to compare the underlying performance of using the traditional microwave frequency at f M Hz versus another frequency, say in mm-band or THz spectrum, specified as f T Hz. Then, the following explicit relations can be derived [23] using the temperature-rise details indicated earlier:…”

“…Nevertheless, it should be prudently recognized that THz radiation can change the profile of genes expression. The reason is as follows: Though THz radiation is not energetic enough to break chemical bonds and ionize biomolecules, the study in [23] reports the possibility of THz field interacting with the double-stranded DNA; and, the resulting resonant effects may allow THz waves to unzip the double strands causing genetic damage. As such, it is stressed here that while advocating TEA, the associated and desired thermal effect (EM heating) being sought for ablation may concurrently induce possible athermal effects.…”

“…Hence, RF ablation techniques have been developed at certain designated frequencies like 915 MHz and 2.45 GHz (ISM band) [23]. The use of a specific frequency and the corresponding wavelength would directly implicate the depth of penetration of EM energy and the associated volume of heating at the ablation zone of interest.…”