To clarify the relationship between whole body average specific absorption rate (SAR) and the rectal temperature elevation in rabbits and to estimate the threshold for inducing a behavioral sign due to microwave provoked thermal stress.The main aim of the study also was to conduct acute dosimetry for high thermal loads due to microwave energy (the experimental conditions were determined with a computational code for electromagnetic-thermal dosimetry via a numeric rabbit phantom).
Rabbits were chosen because of their high susceptibility to heat stress, since they have few sweat glands, and experience difficulty in eliminating excess body heat.
The study was performed with 14 unanesthetized and 10 anesthetized rabbits.
In the current international guidelines for human exposure to microwaves, the limit value is determined by the whole body average SAR value. Although it is known that absorbed microwave energy causes the behavioral sign of thermal stress, the relationship of whole body average SAR with temperature/temperature elevation has not been sufficiently investigated.
Exposure | Parameters |
---|---|
Exposure 1:
2.45 GHz
Exposure duration:
until the core temperature of the rabbit reached 41.5 °C
|
|
Exposure 2:
2.45 GHz
Exposure duration:
until the core temperature of the rabbit reached 41.5 °C
|
|
24 experiments were performed first on anesthetized (10) and then on unanesthetized (14) rabbits. The article does not say how many rabbits were exposed to the individual exposure conditions.
Frequency | 2.45 GHz |
---|---|
Type | |
Charakteristic | |
Exposure duration | until the core temperature of the rabbit reached 41.5 °C |
Exposure source | |
---|---|
Distance between exposed object and exposure source | 1 m |
Setup | rabbit placed in a 10 m x 8 m x 6.5 m anechoic chamber with the bottom of the chamber covered with absorber material; rabbit positioned so that it was irradiated from the lateral side |
Measurand | Value | Type | Method | Mass | Remarks |
---|---|---|---|---|---|
power density | 100 W/m² | spatial average | calculated | - | incident power density |
power density | 220 W/m² | spatial average | calculated | - | incident power density |
SAR | 1.18 W/kg | average over mass | calculated | whole body | for an incident power density of 100 W/m² |
SAR | 1.3 W/kg | average over mass | calculated | whole body | SAR value that caused behavioral signs of stress |
Frequency | 2.45 GHz |
---|---|
Type | |
Charakteristic | |
Exposure duration | until the core temperature of the rabbit reached 41.5 °C |
Exposure source |
|
---|---|
Distance between exposed object and exposure source | 1.2 m |
Setup | rabbit placed in a 10 m x 8 m x 6.5 m anechoic chamber with the bottom of the chamber covered with absorber material; rabbit positioned so that it was irradiated from the lateral side |
Measurand | Value | Type | Method | Mass | Remarks |
---|---|---|---|---|---|
power density | 730 W/m² | spatial average | calculated | - | incident power density |
power density | 980 W/m² | spatial average | calculated | - | incident power density |
SAR | 1.18 W/kg | average over mass | calculated | whole body | for an incident power density of 100 W/m² |
SAR | 1.3 W/kg | average over mass | calculated | whole body | SAR value that caused behavioral signs of stress |
The data suggest that a core temperature elevation of 1°C is an estimate of the threshold inducing complex behavioral signs of microwave-induced thermal stress in rabbits for different whole body exposure average SAR values and exposure durations. The whole body exposure average SAR value required for microwave-induced behavioral signs in rabbits was estimated as approximately 1.3 W/kg for 2.45 GHz microwaves.
This website uses cookies to provide you the best browsing experience. By continuing to use this website you accept our use of cookies.