Influence of tissue mass and exposure duration on correlation between radio frequency energy absorption and induced temperature elevation

The potential risk of tissue heating that may occur from radio frequency (RF) energy absorption during medical procedures is well recognized and regulatory bodies have established or recommended limits on specific absorption rate (SAR) of RF energy. The limits are expressed in terms of 1 g or 10 g of tissue. There has been growing concern about the relationship between SAR and tissue temperature elevation, and the appropriateness of 1g or 10 g averaging tissue mass. This paper examines these issues using an anatomical model of the human body exposed to the field produced by an MRI apparatus.