In the quantification of the CNS concentration of low BBB permeable radiolabeled ligand, the linearity of measured radioactivity concentration from a low level and the contribution of intravascular radioactivity must be considered significant.
This indicates that the contribution of vascular radioactivity at later times became less than in the first few minutes.
The contribution of vascular radioactivity to the regional brain target TACs was corrected prior to analysis, assuming a 5%% blood volume.
To remove the contribution of intravascular radioactivity from the measured brain concentration, Equation 1 can be applied to estimate the net brain concentration Ct(t) using Vb obtained from integration plot analysis (Equation 3).
Thus, a significant contribution of nonspecific radioactivity to the FDG signal at the very early time of 1 h after injection of FDG-labeled cells is unlikely.
We investigated the contribution to radioactivity concentrations from naturally occurring radioactive materials (NORM), including uranium, thorium, actinium, radium, lead, bismuth, and polonium isotopes, to the total radioactivity of hydraulic fracturing wastes.
Contributions of Medical Physics are presented from the early discovery of radioactivity, development of first imaging devices, computers and emission tomography to recent development of hybrid imaging.
The amount of 99mTc metabolites retained in the heart was 12.5 times lower than the values observed with the labeled injected cells (0.21±0.05 vs. 2.62±0.39, respectively) indicating that the contribution of free 99mTc to total myocardium radioactivity can indeed be disregarded.
Take the case of Marie Curie, who discovered two radioactive elements and pioneered the field of radioactivity.
Consider the case of radioactivity.
