| dc.description |
Several positron emitting nuclides with applications in PET, such as <sup>76</sup>Br, <sup>124</sup>I, <sup>110m</sup>In and <sup>86</sup>Y, also emit gamma radiation in their decays. Measured coincidences between annihilation photons and this cascade gamma radiation are essentially true coincidences and the standard PET corrections do not account for them. We investigated the performance of <sup>76</sup>Br in 2D and 3D PET, the effect of the gamma radiation emitted by <sup>76</sup>Br on quantitative accuracy and the distribution of cascade gamma radiation coincidences in 2D and 3D PET sinograms. A correction method for cascade gamma radiation coincidences was implemented and evaluated. Count rate linearity was affected by the gamma radiation from the <sup>76</sup>Br decay. Spatial resolution and sphere recovery were slightly worse for <sup>76</sup>Br compared to <sup>18</sup>F. Correction for cascade gamma radiation coincidences by subtraction of a linear projection tail fit improved total correction accuracy to similar values as for positron-only emitters such as <sup>18</sup>F, and improved image contrast significantly. |
