Calypso® by Varian involves using radiofrequency transponders which are surgically placed in tumours to track and adjust radiation treatment beams due to natural movements of the body, such as breathing.
Radiation therapy for cancer treatment requires the accurate delivery of radiation to the tumour, with as little radiation as possible delivered to the surrounding healthy tissues and organs.
Even when you are lying stationary during radiation therapy, the organs in your body move slightly when you breathe in and out. The precise position of the organs in your body can also shift slightly from day to day due to natural variations in your body. For example, the precise location of a tumour of the prostate can change very slightly depending how full your bladder is or how much gas is present in the rectum.