The EM energy absorption in different rat model exposed to microwave irradiation / 中华放射医学与防护杂志

ABSTRACT

Objective To find out the relationship between the weight and whole body averaged SAR. and the relationship between the weight and the EM energy absorption in rat model exposed to 3 GHz microwave irradiation.Methods Based on 3D rat NMR images,a rat EM model consisting of 45 tissues was established, then by changing the size of model cell,16 models of which the sizes varied from 9 cm to 24 cm, and the weights from 16 g tO 334 g correspondingly were established too.Using FDTD method,the induced electric fields in these rat models were calculated,and then SAR and EM energy absorption have been obtained accordingly.Results The relationship between the weight and the whole body averaged SAR of rat model exposed to 3 GHz microwave irradiation can be divided into three sections,and each of them can be fitted into one line.In small rat section, SAR changed sharply;in middle rat section,SAR changed moderately;in large rat section,SAR changed litflely.The relationship between the weight and the EM energy absorption of rat model were fitted into one quadratic polynomial curve.The EM energy absorption was almost identical when the model is small,with the increasing of the weight,the EM energy absorption also increases,but the increasing ratio of the energy is less than that of the weight.Conclusions Larger rat absorbs more EM energy,but gets less SAR.Exposed to the same irradiation,the dose differences of larger rat is much less than that of smaller rat because of the changes in body weight,so the larger rat is to be recommended.