BAT is a targeting system used with IMRT and occasionally with standard external beam radiation. The system uses ultrasound to verify and correct the position of mobile targets. An example of an organ that moves on a daily basis is the prostate (a target). Using BAT ensures that (despite the target's mobility) the whole target volume is irradiated on a daily basis while treating the least amount of surrounding normal tissue.
BAT is used on a daily basis at the time of treatment. The ultrasound probe images the target and allows the comparison of the current target position with its position at the time of planning. Through this process the patient's position can be adjusted so the target is in the desired location for each treatment.
The use of BAT is appropriate in organs that can be visualized by ultrasound and that move. Dr. Keit will discuss with you if BAT is appropriate in your case.