Calibrating cancer radiotherapy beams using light and sound

Doctors shrink tumors with radiation therapy, but a badly calibrated beam can cause serious complications. Scientists in NIST’s Radiation Physics Division in the Physical Measurement Laboratory (PML) are developing a new set of techniques that could someday take the place of current standards. Their proof-of-concept work demonstrates a potentially better way to calibrate a radiotherapy beam by measuring subtle changes in the temperature of a phantom, or proxy for a person, using ultrasound or optical light.