University of Washington

Division of Nuclear Medicine

Introduction to PET Physics

[Table of contents] [List
of figures] [List of
tables]

[References] [List
of abbreviations] [Copyright
notice]

1. Introduction2. The physical principles of PET

2.1 Introduction

2.2 Positron emission and annihilation

2.3 Coincidence detection and electronic collimation

2.4 Photon interactions in human tissue and correction for gamma-ray attenuation

2.5 Types of coincidence events3.1 Principles of operation

3.2 Sensitivity to true coincidence events

3.3 Sensitivity to scattered events

3.4 Sensitivity to random events

3.5 Effect of camera geometry4.1 Introduction

4.2 Notation and mathematical theorems used

4.3 Analytic image formation in 2D PET

4.4 Filtered Back-Projection in 3D and 3D-RP5.1 Introduction

5.2 Scintillators and scintillation detectors

5.3 Pulse processing

5.4 Coincidence processing

5.5 Dead-time

5.6 Block detectors

5.7 Camera configurations in PET6. Corrections for quantitative PET in 2D and 3D mode

6.1 Introduction

6.2 Attenuation correction

6.3 Correction for random coincidences

6.4 Scatter correction

6.5 Detector normalisation

6.6 Dead-time correction

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Positron emission and annihilation

Coincidence detection in a PET camera

Variation of point source response function (psrf) with position P in SPECT and in PET

Coincidence detection in an attenuating object

Types of coincidences in PET

Axial cut-away view of a multi-ring PET camera (not to scale) operating in 2D mode, showing direct and cross-plane rebinning

Axial cut-away view of a PET camera in 2D and 3D mode showing how the number of possible LORs can increase when the septa are removed

Predicted sensitivity from the number of LORs used in 2D and 3D mode

Effect of septa removal on sensitivity to scattered coincidences

Effect of septa removal on sensitivity to single events

3D co-ordinate system for a full-ring PET camera

Projections generated from a single central point source (3 projections shown)

Back-projections of a point source. With finite numbers of back-projection angles, "star" artefacts are seen

The Ramp and Hanning filters

Parallel projections in 2D. Note that he LORs become closer together towards the edge of the FOV. To correct for this, the data must be re-sampled (

arc corrected) prior to reconstructionParallel projections in 3D

Axial cut-away diagram of a PET camera operating in 3D mode, showing the extent of the projection sets as a function of angle j

Features of a typical energy distribution for electrons involved in interactions with 511 keV photons

Features of a typical energy distribution measured by a scintillation detector system exposed to 511 keV photons

Schematic diagram showing coincidence processing in a PET camera

A block detector

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Examples of radiotracers and their applications

Properties of commonly used positron emitting radio-isotopes

Notation for spatial and Fourier quantities

Examples of scintillators and their properties

Last revised by:

Revision date:12 Jan 1999