PET system calibration and attenuation correction

Standard system calibration and attenuation correction in PET has high statistical noise and is susceptible to wild fluctuation, especially in low count studies. A two-part remedy is proposed involving first an estimation of machine related factors and second a smoothing of calibrated transmission scan. The key to the first part is statistical modelling and estimation of the blank scan sinogram data, which capture the detector nonuniformities and geometric effects. Machine-calibrated transmission data approximately reflect pure attenuation effects, which is a smooth function plus some Poisson noise, so noise reduction is achieved by a smoothing step. The proposed technique is illustrated with studies on the GE Advance PET Scanner