Positron emission tomography (PET) [1] is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, …

We conclude that the sudden increase in temperature and humidity in PET/CT equipment room affects the performance of scanner which reflects as count deficit in the image. This impairment in the image quality may be because of bismuth germanate crystal, photomultiplier tubes, and associated electronics.

Current PET systems do not allow acquisition of positronium images. This study presents a new method that enables positronium imaging by simultaneous registration of annihilation photons and deexcitation photons from pharmaceuticals labeled with radionuclides.

The single most important physical effect in PET imaging: • The number of detected photons is significantly reduced compared to the number of positron decays in a spatially-dependent manner • For PET it is due to Compton scatter out of the detector ring • For CT it is a combination of Compton scatter and photoelectric absorption one 511 ...

2015年8月6日 · We have given an approximate estimate of the range of slow positrons in an idealized PET environment by solving Boltzmann’s equation incorporating the best available set of cross sections for low-energy positron-water scattering processes.

2005年4月18日 · PRINCIPLES OF POSITRON EMISSION TOMOGRAPHY PET is based on the detection of very small (picomolar) quantities of biological sub- stances which are labelled with a positron emitter. Most commonly used are carbon- 11, oxygen-15, nitrogen-13, and fluorine-18.

Positron emission tomography (PET) plays a central role in the molecular imaging landscape due to its high sensitivity, accurate quantification, tomographic readout, and diverse applications. While the positron-emitting 2-deoxy-2-[18 F]fluoro-D-glucose largely dominates contemporary clinical PET, PET technology/machines are readily capable of ...

PET imaging begins with the injection of a metabolically active tracera biological molecule that carries with it a positron-emitting isotope (for example, 11 C, 13 N, 15 O, or 18 F). Over a few minutes, the isotope accumulates in an area of the body for which the molecule has an affinity.

What Do We Need for PET Detector? Efficient – 511keV gamma rays are not easily stopped in detector. Excellent timing accuracy (typically a few ns) – for coincidence measurements. High detector spatial resolution – for high imaging resolution. Cost‐effective – very large detector volume is needed for practical PET systems.

2024年5月20日 · Through annihilation, the mass of an electron and the positron is converted into electromagnetic energy, which is released as two high-energy photons (511 keV) in a random direction 180º±0.25 º (non-collinearity) apart. These high energy photons have a high chance to leave the body and therefore can be detected during PET measurements (see figure).