Study type: Medical/biological study (experimental study)

In vitro studies of microwave-induced cataract: separation of field and heating effects. med./bio.

Published in: Exp Eye Res 1983; 36 (1): 75-90

Aim of study (acc. to author)

To investigate the effects of pulsed microwave irradiation on rat eye lens in vitro.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Modulation type: pulsed
Exposure duration: continuous for 5 min
Exposure 2: 915 MHz
Modulation type: CW
Exposure duration: continuous for 5 min

Exposure 1

Main characteristics
Frequency 915 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 5 min
Modulation
Modulation type pulsed
Pulse width 10 µs
Rise time 100 ns
Additional info

Average power was set by variation of the pulse repetition rate.

Exposure setup
Exposure source
Chamber The lens temperature was maintained to ± 0.25°C by a thermostatically controlled glass holder circulating saline around the lens.
Setup The lens holder was placed in the waveguide at one quarter wavelength from the shorting plate, i.e. in the E-field maximum, with the lens approx. at the center of the waveguide.
Sham exposure A sham exposure was conducted.
Additional info Exposures were performed at 37, 39, and 41°C. Sham exposures were conducted at identical temperatures of circulating coolant with microwave power off. Some exposures even lasted 20 min, e.g., 60 W at 37°C.
Parameters
Measurand Value Type Method Mass Remarks
power 24 kW peak value measured - 20-24 kW
power 6 W mean measured - -
SAR 120 mW/g mean measured - -
power 20 W mean measured - -
SAR 400 mW/g mean measured - -
power 60 W mean measured - -
SAR 1,200 mW/g mean measured - -

Exposure 2

Main characteristics
Frequency 915 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 5 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 6 W mean measured - -
SAR 120 mW/g mean measured - -
power 20 W mean measured - -
SAR 400 mW/g mean measured - -
power 60 W mean measured - -
SAR 1,200 mW/g mean measured - -

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No morphological changes could be observed in unexspoed control samples. Pulsed microwave exposure was carried out under different controlled temperatur conditions (37°C and 39°C) and at different SAR values. Several kinds of damage could be detected by electron microscopy, such as holes, foam, large globules and capsular damage. At the higher temperature of 39°C the damages were more extensive. The amount of damage also increased in proportion to the SAR values.

Study character:

Study funded by

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