Invited Talk by Prof. Michel Defrise: Time-of-flight PET reconstruction with simultaneous estimation of the attenuation factors

Prof. Michel Defrise In Vivo Cellular and Molecular Imaging ICMI, Vrije Universiteit Brussel Date: Friday, March 15, 2013 Time: 15:00 - 16:30 Location: Hörsaal Pavillon, Klinikum rechts der Isar, Ismaninger Str. 22, 81675 München

Time-of-flight PET reconstruction with simultaneous estimation of the attenuation factors

In positron emission tomography (PET), a quantitative reconstruction of the tracer distribution requires accurate attenuation correction. The attenuation correction is usually based on information obtained from transmission tomography (CT) or from MRI. We will discuss situations where such a direct measurement of the attenuation coefficient of the tissues is not available, unreliable, or incomplete. Methods to simultaneously estimate both the tracer distribution and the attenuation using only the emission time-of-flight PET data will be presented. We will first demonstrate that the attenuation is determined by the emission time-of-flight data except for a constant factor. Next, we will describe an iterative algorithm to calculate the maximum-likelihood estimator of the tracer distribution, which avoids the reconstruction of the attenuation image. Examples with simulated data and with preliminary data will illustrate the properties and limitations of this approach and the potential applications of this algorithm.