Qualitative Analysis of Human Semen Using Microwaves

Abstract

Microwave engineering now a days plays a vital tool in diagnostic and therapeutic medicine. A quality evaluation of human semen at microwave frequencies using the measurements made at different intervals of time by cavity perturbation technique in the S-band of microwave spectrum is presented in this paper. Semen samples were also examined in the microscopic as well as macroscopic level in clinical laboratory. It is observed that conductivity of semen depends upon the motility of sperm and it increases as time elapses, which finds applications in forensic medicine. Accurate information about the dielectric properties of tissues and biological liquids is important for studies on the biological effects at radio and microwaves frequencies. In macroscopic level, these electrical properties determine the energy deposition patterns in tissue upon irradiation by an electromagnetic field. In microscopic level, they reflect the molecular mechanisms, which underlie the absorption of electromagnetic energy by the tissue or liquids. Knowledge of the microwave dielectric properties of human tissues is essential for the under- standing and development of medical microwave techniques. Microwave thermography, microwave hyperthermia and microwave tomography all rely on processes fundamentally determined by the high frequency electromag- netic properties of human tissues. Tissue temperature pattern retrieval in the microwave thermography is achieved using models of the underlying tissue structure, which depend particularly on the dielectric properties of the tissue (1). A recent review of published data on animal and human dielectric parameters shows that for most tissue types animal measurements are good substitute for human tissues (2). Gabriel etal., Cook and Land etal., reported the dielectric parameters of various human tissues at different RF frequencies.(3-6). Microwave study of human blood using coaxial line and wave-guide methods was carried out by Cook (7). Tissue samples of human brain at microwave frequencies were analysed using sample cell terminated transmission line methods (8). Open-ended coaxial line method allows measurements of tissue samples over a wide range of frequencies (9). Microwave medical tomography is emerging as a novel non-hazardous method of imaging for the detection of fracture, swelling and diagnosis of tumors. Active and passive microwave imaging for disease detection and treatment monitoring require proper knowledge of body tissue dielectric properties at the lower microwave frequencies (10-12). Studies on the variation of dielectric properties of body fluids and urinary calcifications at microwave frequencies have revealed that diagnosis is possible through cavity perturbation technique (13-15). The present paper reports dielectric properties of semen at microwave frequencies as well as the quantitative analysis in the clinical laboratory. It is observed that conductivity of semen depends upon the motility of sperm as well as the time elapses after ejaculation. 2. Materials and Methods The experimental set-up consists of a transmission type S-band rectangular cavity resonator, HP 8714 ET network analyser. The cavity resonator is a transmission line with one or both ends closed. The resonant frequencies are determined by the length of the resonator. The resonator in this set-up is excited in the TE10� mode. The sample holder which is made of glass in the form of a capillary tube flared to a disk shaped bulb at the bottom is placed into the cavity through the non-radiating cavity slot, at broader side of the cavity which can facilitate the easy movement of the holder. The resonant frequency fo and the corresponding quality factor Qo of the cavity at each resonant peak with the empty sample holder placed at the maximum electric field are noted. The same holder filled with known amount of sample under study is again introduced into the cavity resonator through the non-radiating slot. The resonant frequencies of the sample loaded cavity is selected and the position of the sample is adjusted for maximum perturbation (i.e., maximum shift of resonant frequency with minimum amplitude for the peak). The new resonant frequency fs and the quality factor Qs are noted. The same procedure is repeated for other resonant frequencies.