放射線器材學（包括磁振學與超音波學）題庫下載題庫

Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. It can also refer to absorption of other forms of energy by tissue, including ultrasound.^[1] It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).