Spatiotemporal reconstruction of list-mode PET data

Thomas E. Nichols, Jinyi Qi, Evren Asma, Richard M. Leahy

Research output: Contribution to journalArticlepeer-review

151 Scopus citations


We describe a method for computing a continuous time estimate of tracer density using list-mode positron emission tomography data. The rate function in each voxel is modeled as an inhomogeneous Poisson process whose rate function can be represented using a cubic B-spline basis. The rate functions are estimated by maximizing the likelihood of the arrival times of detected photon pairs over the control vertices of the spline, modified by quadratic spatial and temporal smoothness penalties and a penalty term to enforce nonnegativity. Randoms rate functions are estimated by assuming independence between the spatial and temporal randoms distributions. Similarly, scatter rate functions are estimated by assuming spatiotemporal independence and that the temporal distribution of the scatter is proportional to the temporal distribution of the trues. A quantitative evaluation was performed using simulated data and the method is also demonstrated in a human study using 11C-raclopride.

Original languageEnglish (US)
Pages (from-to)396-404
Number of pages9
JournalIEEE Transactions on Medical Imaging
Issue number4
StatePublished - Apr 2002


  • Calibration
  • Conjugate gradient methods
  • Estimation
  • Poisson processes
  • Smoothing methods
  • Spline functions

ASJC Scopus subject areas

  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Electrical and Electronic Engineering
  • Computer Science Applications
  • Computational Theory and Mathematics


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