The relationship between localised SAR in the arm and wrist current

Area of Science:

• Biophysics
• Computational Electromagnetics
• Medical Physics

Background:

• Understanding radiofrequency (RF) energy absorption in human tissues is crucial for safety assessments.
• The lower arm, particularly the wrist, presents unique anatomical challenges for SAR calculations due to its composition.
• Induced currents in biological tissues are a key factor in evaluating potential health effects of electromagnetic fields.

Purpose of the Study:

• To calculate the specific energy absorption rate (SAR) in the lower arm using the NORMAN voxel model.
• To investigate the distribution and magnitude of SAR values for induced currents ranging from 100 kHz to 80 MHz.
• To analyze the impact of wrist anatomy on current channeling and localized SAR.

Main Methods:

• Utilized the NRPB anatomically realistic voxel model named NORMAN.
• Performed electromagnetic calculations to determine SAR for induced currents.
• Averaged SAR values over 10 g and 100 g of tissue as a function of wrist current.

Main Results:

• The narrow cross-section and low muscle content of the wrist region were observed.
• Significant current channeling occurred through the high-conductivity muscle tissue in the wrist.
• This channeling resulted in high, localized SAR values within the wrist region.

Conclusions:

• The anatomical structure of the wrist significantly influences current distribution and SAR.
• Localized high SAR values in the wrist warrant specific attention in exposure assessments.
• The study provides valuable data for evaluating the safety of RF exposure in the lower arm.