PET scanners
TP-1 Spatial resolution
Spatial resolution of a system defines its ability to depict two point sources as distinct in a reconstructed image. It is typically defined as the full-width at half-maximum (FWHM) of a point spread function (PSF) and is calculated from the line profile through a reconstructed image of a point source of radioactivity in air.
TP-2 Sensitivity
Sensitivity is a measure of the number of counts (coincidence detection events) per second per unit activity in the FOV of the PET scanner.
TP-3 Count rate performance
The count rate and scatter fraction performance measurement is used to evaluate the count losses of the system under varying amounts of radioactivity present in the FOV of the PET scanner.
TP-4 Accuracy of random event corrections
Assessment of the goodness of the corrections that the system applies to the data acquired after characterizing these two parameters.
TP-5 Image quality
Evaluate image quality using a phantom with hot and cold spots to simulate clinical studies. This test allows you to calculate attenuation and dispersion corrections as well as quantify absolute measurements of activity in a volume of interest.
TP-6 Energy resolution
Determines the accuracy with which the scanner can measure the energy of the 511 keV photon interactions and affects the ability to reject scatter coincidences where at least one of the two 511 keV photons has incident energy <511 keV.
TP-7 Time-of-flight (TOF)
Determine the ability of the system to calculate the difference in arrival time of the two coincident photons, and obtain information on the likely location of annihilation along the line of response (LOR).
TP-8 Stability
Evaluate the consistency of the detector system's operation and detect any incipient or sudden changes.
TP-9 Normalization
Corrects sensitivity differences caused by variations in detector efficiency, subtended solid angle, summation of data from neighboring elements, and different block separations. It is applied during the reconstruction process, correcting the images for the variation in the efficiency of the lines of response (LOR) in each slice."
TP-10 Activity concentration calibration
Assign factors that convert reconstructed events to activity in the image. These factors used in the calculation of activity concentration and SUV, correlate the pixel values in each image with the specific activity measured.
