Comparison of scandium-44 g with other PET radionuclides in pre-clinical PET phantom imaging

Abstract

PurposeThe decay characteristics of radionuclides in PET studies can impact image reconstruction. 44gSc has been the topic of recent research due to potential theranostic applications and is a promising radiometal for PET imaging. In this study, the reconstructed images from phantom measurements with scandium in a small-animal PET scanner are compared with 18F and two prominent radiometals: 64Cu and 68GaMethodsThree phantoms filled with 18F, 64C, 68Ga, and 44gSc were imaged in the Siemens Inveon PET scanner. The NEMA image quality phantom was used to determine the recovery coefficients (RCs), spill-over ratios (SORs), and noise (%SD) under typical pre-clinical imaging conditions. Image contrast was determined using a Derenzo phantom, while the coincidence characteristics were investigated using an NEC phantom. Three reconstruction algorithms were used, namely filtered back projection (FBP), ordered subset expectation maximization (OSEM), and maximum a-posteriori (MAP).ResultsImage quality parameters were measured for 18F, 64Cu, 68Ga, and 44gSc respectively; using FBP, the %SD are 5.65, 5.88, 7.28, and 7.70; the RCs for the 5-mm rod are 0.849, 1.01, 0.615, and 0.825; the SORs in water are 0.0473, 0.0595, 0.141, 0.0923; and the SORs in air are 0.0589, 0.0484, 0.0525, and 0.0509. The contrast measured in the 2.5-mm rods are 0.674, 0.637, 0.196, and 0.347. The NEC rate with 44gSc increased at a slower rate than 18F and 68Ga as a function of activity in the field of view.Conclusion44gSc demonstrates intermediate behavior relative to 18F and 68Ga with regard to RC and contrast measurements. It is a promising radionuclide for preclinical imaging.

High yield cyclotron production of a novel 133/135La theranostic pair for nuclear medicine

“…However, positrons emitted by 132 La have a much higher 1.29 MeV average and 3.67 MeV maximum energy compared to 133 La positron emissions, which have a low, more desirable 0.463 MeV average and 1.02 MeV maximum positron energy. Since higher positron energies are correlated with lower PET imaging spatial resolution 14 , 15 , this implies that 133 La would have superior PET imaging quality compared to 132 La.…”

“…The 132 La 465 keV (76%) and 567 keV (14.7%) high abundance gamma rays are within a typical 350–650 keV PET scanner energy window used to detect the 511 keV annihilation gamma rays 15 , which could lead to excess spurious coincidences within the scanner timing window, and interfere with image quality. 133 La has no gamma rays with energies within a typical PET scanner energy window, which should result in no spurious coincidences.…”

Measurement and modeling of proton-induced reactions on arsenic from 35 to 200 MeV

“…EMPIRE, CoH, and ALICE underpredict the high-energy pre-equilibrium tail for 72 As relative to TALYS and TENDL, though the former trio of codes have the better energy placement of the compound peak centroid. The production of 44g Sc (t 1/2 = 3.97 (4) h [83]) is of general interest as an emerging radiometal for nuclear imaging and theranostic purposes [3,82,84,85].…”

Dual Probes for Positron Emission Tomography (PET) and Fluorescence Imaging (FI) of Cancer

“…Some of the most commonly used radionuclides discussed in this review include 18 F, 64 Cu, 68 Ga, 89 Zr, and 124 I ( Table 1 ) [ 13 ]. However, some recent advances have led to the development of more exotic radionuclides for research, such as 44g Sc, 132 La, and 133 La ( Table 1 ) [ 14 , 15 , 16 , 17 ]. The physical half-life of the radionuclide should generally match the biological half-life of the radiotracer in vivo.…”