Table 1.  Peak temperatures in the skin surface and muscle induced by microwave hyperthermia at two radio frequencies. Because a warm water bolus was placed on the thigh before treatment, the baseline skin temperature increased in the 434-MHz system.
 

Baseline T
ēC

Peak T
ēC

Temperature rise
ēC

Time to peak T
min

434-MHz system

        

Skin surface

        

Mean (SD)

34.2 (1.4) *

39.2 (.5)

5.0 (1.5) *

10.7 (1.6)

Range

31.6-35.9

38.2-39.8

3.1-8.2

8.4-13. 7

Muscle

        

Mean (SD)

35.0 (1.3)

43.7 (.8) **

8.9 (1.4) **

9.9 (1.4) **

Range

33.2-37.9

42.8-45.4

6.3-11.4

8.4-12.5

2450-MHz system

        

Skin surface

        

Mean (SD)

32.3 (1.1)

39.2 (.8)

6.9 (1.5)

15.9 (7.3)

Range

30.8-33.9

38.0-40.6

4.1-8.3

4.8-30.2

Muscle

        

Mean (SD)

35.0 (.8)

41.1 (1.3)

6.1 (1.4)

20.0 (7.5)

Range

33.6-36.0

39.6-43.2

3.9-8.5

9.5-30.3
* and ** denote p < 0.05 and 0.01, respectively compared with 2450-MHz system.