Distance between exposed object and exposure source
The subjects sat on an armchair at a distance of 70 cm in front of a loudspeaker inside a shielded, soundproof and temperature-controlled room.
The mobile phone was held by a helmet in the normal use position (antenna oriented to the temporoparietal area) at 1.5 cm from the right ear tragus. An identical phone, but without battery, was placed on the left side of the helmet to balance the weight.
Each participant attended two experimental sessions, one week apart, providing either real or sham exposure in counterbalanced order and following a double-blindparadigm. Each session lasting 85 min comprised four 10-min phases of data collecting (T0-baseline, T1, T2, T3) and between them, three 15-min phases of real or sham exposure.
SAR distribution was measured using a calibrated commercial isotropic EFsensor positioned by an automatic three-dimensional scanning system inside homogeneous anthropomorphic head-shaped and cube-shaped (20 x 20 x 20 cm³) phantoms [Guelfi et al., 1997; Lovisolo et al., 2001] both filled with a semi-liquid material electromagnetically equivalent to braintissue. The absolute uncertainty of SAR measurements was within 20%.