- Tytuł:
- First positronium lifetime imaging with scandium-44 on a long axial field-of-view PET/CT
- Autorzy:
-
Mercolli, Lorenzo
van der Meulen, Nicholas P.
Schibli, Roger
Seifert, Robert
Moiseeva, Anzhelika
Stępień, Ewa
Steinberger, William M.
Moskal, Paweł
Rathod, Narendra
Sari, Hasan
Conti, Maurizio
Grundler, Pascal V.
Shi, Kuangyu
Braccini, Saverio
Rominger, Axel - Opis:
- 4Purpose: The physical properties of $^{44}$Sc, combined with its imminent clinical application, position it as a prime candidate for in vivo positronium lifetime imaging. In this study, we investigate the count statistics for ortho-positronium (oPs) measurements with $^{44}$Sc on a commercial long-axial field-of-view (LAFOV) PET/CT. Method: A NEMA image quality phantom was filled with 41.7 MBq of $^{44}$Sc dissolved in water and scanned on a LAFOV PET/CT. Three-photon events were identified using a prototype feature of the scanner and dedicated software. The lifetime of oPs was determined in the phantom spheres and in 4 $\times$ 4 $\times$ 4 mm$^{3}$ voxels. Results: All measured oPs lifetimes are compatible, within the uncertainties, with the literature values for water. The oPs lifetime is 2.65 ± 0.50, 1.39 ± 0.20 and 1.76 ± 0.18 ns in the three smallest spheres of the phantom and 1.79 ± 0.57 ns for a single voxel in the central region of the largest sphere. The relative standard deviation in the background regions of the time difference distributions, i.e., for time differences smaller than -2.7 ns, is above 20%—even for voxels inside the phantom spheres. Conclusions: Despite the favorable physical properties of $^{44}$Sc, the count statistics of three-photon events remains a challenge. The high prompt-photon energy causes a significant amount of random three-photon coincidences with the given methodology and, therefore, increases the statistical uncertainties on the measured oPs lifetime.
- Dostawca treści:
- Repozytorium Uniwersytetu Jagiellońskiego
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