Nine well ventilated radial transmission line (RTL) exposure chambers were placed in three racks, each rack containing one exposure chamber for each of the three exposure conditions. Each exposure chamber consisted of two parallel circular aluminium plates with 150 cm diameter and 15 cm separation. The edges of the plates were shorted with a metallic wall covered with a ring of absorbing material to reduce reflections.
Twenty-four ventilated polycarbonate cages having the shape of a truncated wedge (17 to 8.5 cm wide, 35 cm long, and 15 cm high), each containing an unrestrained rat, were placed symmetrically in the chamber with their wider end near the absorbing material. A tuneable monopole antenna at the center generated a radial plane wave. The EF was vertical (perpendicular to the plates) and the MF was circumferential, parallel to the plates.
Four groups of 72 animals each were treated as follows: cage control, MX + sham exposure, MX + 0.3 W/kg, and MX + 0.9 W/kg. The three chambers of each exposure group were always in different racks and at different rack levels.
The background ELFMF was below 0.1 µT, the static MF was 40-47 µT in the animal room. The stray RF fields at a distance of 0.15 m from the exposure chamber were 1 W/m² or lower, and far below 0.1 W/m² at a distance of 1 m.
Mess- und Berechnungsdetails
Forward and reflected powers at the input of the exposure chambers were measured with RF power meters. The whole-body average SARs for rats in the center of the cage with their noses pointing at the center of the chamber were determined based on 1) analytical calculations with homogeneous prolate spheroidal rat models and on 2) calorimetric measurements using homogeneous rat phantoms consisting of plastic flasks filled with liquid simulating muscle, and were 3) confirmed by FDTD calculations [Puranen et al., submitted]. The resulting SARs decreased linearly with increasing rat mass from 100 g to 320 g and varied with different horizontal positions. For small rats (<110 g), the highest SAR may have been 1.2 W/kg for the low-level exposure and 3.6 W/kg for the high-level exposure if the rat was standing in an upright position.
Heikkinen P et al.
Erratum to "No effects of radiofrequency radiation on 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone-induced tumorigenesis in female Wistar rats" Heikkinen P et al., Radiat Res 2006; 166 (2): 397 - 408
Zeni O et al.
Formation of reactive oxygen species in L929 cells after exposure to 900 MHz RF radiation with and without co-exposure to 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone.
Shirai T et al.
Lack of promoting effects of chronic exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular system on development of N-ethylnitrosourea-induced central nervous system tumors in F344 rats.