Evaluation of the proper level of specific absorption rate of human blood for 532 nm laser in blood low-level laser therapy

Abstract

Low-level laser has been used for a variety of clinical applications as a practical nonmedicinal treatment, due to its ability to modulate blood rheology and improve biostimulation. This article research aim was to evaluate the proper level of specific absorption rate (SAR) of human blood during low-level laser treatment. Measurements were conducted on human blood in vitro, at different laser powers (wavelength 532 nm at powers of 50, 60, 70 and 80 mW) and exposure duration. Dielectric parameters were observed as a function of frequency from 40 Hz-30 MHz by utilizing an Agilent 4294A impedance analyzer at average room temperature of 25 °C. The SAR increased steadily with increasing frequency until it attained saturation peak, and thereafter exhibited a decrease trend. The SAR values range from 0.173-1.417 W kg −1 for blood irradiated using laser power of 50 mW and range from 0.178-0.754 W kg −1 for 60 mW. These values of SAR within 5-10 min of radiation present better stimulation results. Using laser powers of 70 and 80 mW for irradiations, the SAR values within the range from 0.003-0.791 W kg −1 and 0.130-0.491 W kg −1 , respectively, were computed. The SAR values here portend high risk associated to blood than its stimulation mechanism because the blood already attained a plateau and became saturated. This causes imbalance within the blood molecules resulting in a decrease in SAR as the frequency increases. This is due to a phase lag that develops between the electric field and induced dipole alignment creating a significant drop in the SAR of blood. The rate of inhibition increases rather than stimulation since the thermal radiation becomes exceedingly high resulting in crenation and hemolyzation of the blood. Therefore, we recommend using a laser at an output of power 50 mW for 5-10 min to reach the maximum capacity of SAR for more absorption and optimal stimulation.

Influence of Na+ disorder on cytoplasmic conductivity and cellular electromagnetic (EM) energy absorption of human erythrocytes (PONE-D-21-36089)

“…High electromagnetic field intensity emitted from X-ray equipment may increase cytoplasmic conductivity and consequently SAR of HRBC in case of hyponatremia or hypernatremia or even in normal blood. Increase of SAR values of blood at 37°C ranging from 0.173–1.417 W kg −1 by irradiation with 532 nm laser power of 50 mW for 5–10 min has been reported [ 49 ].…”

Biostimulation Effects and Temperature Variation in Stimulated Dielectric Substance (Diabetic Blood Comparable to Non-Diabetic Blood) Based on the Specific Absorption Rate (SAR) in Laser Therapy

“…The smeared of exposed blood for more than 15 minutes produce unsatisfactory results. Where there are free intracellular Ca +2 concentrations that affect the efflux of K + ions [12,16], it results in the crenation of the blood cells as in Figure 4. This is due to excess free radicals that caused changes in the molecular chemical structures as well as confirmation by altering H-bonds of membrane proteins [1,18,19].…”

“…where δ is called the loss angle, tan δ is called dielectric loss tangent and for low-loss dielectrics, δ is very small, σ is the conductivity of the blood (S/m), ε 0 is the permittivity of free space (8.854×10 −12 F/m), ω = 2π f ( f is the frequency in Hz), ρ is the density of the blood (kg/m 3 ) and ε r is the relative permittivity. |E| 2 is the electric field strength (field amplitude) (V 2 /m 2 ) of the wave (beam) [9,16,17]. The wave energy is proportional to the square of the amplitude (E 2 ), where the amplitude is proportional to pressure.…”

“…It is unlikely for a significant temperature increase in the brain to occur as a result of perfusion but SAR limits in any 1 g of head tissue may be exceeded. The SAR values are relative to measured temperature changes which had a sharp increase in absorbed heat especially at the place near the ear skull due to constantly used of mobile phones [4,7,8,14,15,16,17].…”

Therapeutic exposure of diabetic blood using 532 nm-wavelength low level laser through electrical impedance spectroscopy (EIS).

“…An Impedance analyser (Agilent 4294 A) of 40 Hz-30 MHz frequency range was used for the blood impedance measurements [6][7] by connecting the electrodes of the designed cuvettes to it though medium Kelvin clip lead. Records of blood capacitance and loss-energy of the samples were obtained, then further analysis and evalaution for the dielectric properties; dielectric permittivity 𝜀 ′ , loss 𝜀 ′′ , conducttivity and blood impedance.…”