Study type: Medical/biological study (experimental study)

Effects of 20-MHz radiofrequency radiation on rat hematology, splenic function, and serum chemistry med./bio.

By: Wong LS, Merritt JH, Kiel JL
Published in: Radiat Res 1985; 103 (2): 186-195
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Aim of study (acc. to author)

To investigate the effects of 20 MHz radiofrequency radiation on rat hematology, spleen function, and serum chemistry.

Background/further details

Two different experiments with separate sets of rats but under identical exposure levels, each with unexposed controls were carried out.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 20 MHz
Modulation type: CW
Exposure duration: repeated daily exposure, 6 h/day, 5 days/week, for 8, 22 and 39 days
Experiment 1
Exposure 2: 20 MHz
Modulation type: CW
Exposure duration: repeated daily exposure, 6 h/day, 5 days/week, for 6 weeks
Experiment 2

Exposure 1

Main characteristics
Frequency 20 MHz
Type
Charakteristic
  • guided field
Exposure duration repeated daily exposure, 6 h/day, 5 days/week, for 8, 22 and 39 days
Additional info Experiment 1
Additional info Experiment 1
Modulation
Modulation type CW
Exposure setup
Exposure source
  • TEM cell
  • 4.75 x 9.25 x 30 ft with a 6 ft wide center conductor
Chamber Two hundred male rats (280-300 g) were divided into 40 groups and housed, five rats each, in plastic cages of 55 x 31.5 x 20 cm. Twenty cages were randomly selected for control and 20 for exposure. Ambient conditions were similar for control and exposed groups.
Setup Cages were spaced 30 cm apart and were rotated through all positions to avoid continuous exposure of a particular cage to a field higher or lower than average. Empty cages were used to fill positions from which cages of sample rats had been removed.
Sham exposure A sham exposure was conducted.
Additional info Control cages were placed in a holding rack immediately outside the TEM chamber during exposure periods.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2,686.5 V/m mean measured - ± 163.6 V/m
power density 1,920 mW/cm² mean calculated - -
SAR 0.26 W/kg mean calculated whole body worst case 0.3 W/kg
Measurement and calculation details

Fields were measured at each of the 20 cage sites using a 10-cm dipole and loop antennas. SARs could not be measured because of the low power absorption of the live, moving animals but were calculated for a 320-g rat according to [Durney et al., 1980] to be 0.12 W/kg in H-polarization, 0.17 W/kg in K-polarization and 2.49 W/kg in E-polarization. The maximum SAR was averaged from the percentage of time spent in each orientation (less than 5% upright) and the worst case was determined for all animals huddled together approximated as a single tissue mass.

Exposure 2

Main characteristics
Frequency 20 MHz
Type
Charakteristic
  • guided field
Exposure duration repeated daily exposure, 6 h/day, 5 days/week, for 6 weeks
Additional info Experiment 2
Additional info Experiment 2
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber Twenty-four male rats were randomly divided into three control and three exposed groups of four animals each. Each rat was housed in a separate cage.
Sham exposure A sham exposure was conducted.
Additional info The treatment of the groups was staggered by 1-week intervals.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2,686.5 V/m mean measured - ± 163.6 V/m
power density 1,920 mW/cm² mean calculated - -
SAR 0.26 W/kg mean calculated whole body -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Overall no significant differences between exposed and control animals were found.
In the first experimental group differences in spleen weight and in the number of erythrocytes and hemoglobin were observed. But these findings could rather be ascribed to an mycoplasmas infection of the animals than to exposure.

Study character:

Study funded by

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