Radiofrequency electromagnetic fields have no effect on the in vivo proliferation of the 9L brain tumor

The intracranial 9L tumor model was used to determine if exposure to a radi ofrequency (RF) electromagnetic field similar to those used in cellular tel ephone has any effects on the growth of a central nervous system tumor. Fis cher 344 rats implanted with different numbers of 9L gliosarcoma cells were exposed to 835.62 MHz frequency-modulated continuous wave (FMCW) or 847.74 MHz code division multiple access (CDMA) RF field with nominal slot-averag e specific absorption rates in the brain of 0.75 +/- 0.25 W/kg, The animals were exposed to the RF field for 4 h a day, 5 days a week starting 4 weeks prior to and up to 150 days after the implantation of tumor cells. Among s ham-exposed animals injected with 2 to 10 viable cells (group 1), the media n survival was 70 days, with 27% of the animals surviving at 150 days. The median survival length and final survival fraction for animals injected wit h 11 to 36 viable cells (group 2) were 52 days and 14%, respectively, while the values for those injected with 37 to 100 cells (group 3) were 45 days and 0%. The animals exposed to CDMA or FMCW had similar survival parameters , and the statistical comparison of the survival curves for each of the gro ups 1, 2 and 3 showed no significant differences compared to sham-exposed c ontrols. (C) 1999 by Radiation Research Society.