(FWHM) The full width at half maximum is a parameter to characterize the width of a peak on a graph. In nuclear medicine, the FWHM is used to determinate the energy resolution of gamma camera systems.

(FWTM) The width of a Gaussian or Lorentzian type curve at the tenth of its maximum height (full width at half maximum (FWHM)) and a quality measure of the sharpness of a peak (frequency peak, resolution peak) used less frequently than the FWHM measure.