Review of Richard Horton (2020). The Covid-19 Catastrophe: What's Gone Wrong and How to Stop it Happening Again

Zoe Hurley


Background This investigation used image data generated by an anthropomorphic phantom to determine the minimal 99m Tc rest-stress activity concentration ratio (R) able to minimize the ghosting effect in the single-day stress-first myocardial perfusion imaging, using different positions of the perfusion defect (PD), scanners and reconstruction protocols Methods A cardiac phantom with a simulated PD was imaged under different R using different gamma cameras and reconstruction algorithms The residual activity from precedent stress administration was simulated by modeling effective half-times in each compartment of the phantom and assuming a delay of 3 hours between the stress and rest studies The net contrast (NC) of the PD in the rest study was assessed for different R, PD positions and scanner/software combinations The optimal R will be the one that minimize the NC in the rest images Results The activity concentration ratio R, the position of the PD and the scanner/software combinations were all main effects with a statistically significant impact on the NC, in decreasing order of relevance The NC diminished significantly only for R values up to 2 No further improvement was observed for NC for R values above 2 and up to 3 NC was significantly higher in anteroseptal than in posterolateral positions of the PD and higher for solid-state cameras Conclusions A rest-stress activity concentration ratio R of 2 in single-day stress-first myocardial perfusion imaging is enough to achieve the maximum net contrast in the PD This ratio should be used to optimize patient's radiation exposure (J Nucl Cardiol 2020) Key Words: Myocardial perfusion imaging: SPECT AE patient radiation dose AE single-day protocol AE stress-first protocol Electronic supplementary material The online version of this article (https://doi