Technical progress of SPECT/CT has in the last years been impressive, including, in particular, the option to quantify tracer uptake in absolute units, the introduction of semi-conductor detectors, and the development of multimodal image reconstruction methodology (Ritt et al. 2014).
We first estimate the "absolute" cost of amino acid synthesis by examining the sensitivity of nutrient uptake in the cell to small absolute changes in the stoichiometric requirement of each amino acid for growth in the FBA model.
However, tetrofosmin is cleared more rapidly from the liver and the absolute uptake in the heart is lower.
Estimates of incremental health impact are subject to the variation in current treatment uptake, as both the absolute and relative (i.e. in relation to alternative interventions) health impact of an intervention will vary if the treatment uptake of the same or other interventions change.
As expected, overall uptake was low and there was a marked difference in the absolute amount of NP uptake in the presence and absence of serum (∼2-fold higher uptake without serum).
However this comes at the cost of around a tenfold reduction in the absolute tumor uptake and a tenfold increase in renal retention of radioactivity.
A strength of this study lies in the large dataset of individual level records included in the final analysis (n = 205, 541), which made it possible to detect absolute differences in uptake in the magnitude of 1 to 2% and also take into account other demographic characteristics that could have confounded the effects of the intervention groups on uptake.
To assess the volume of [F]FMISO uptake in tumours, different absolute thresholds were used, ranging from 1.2 to 3.0.
Compared to measuring DPD uptake in absolute units, visual evaluation of skeletal scintigraphies for change in tumor metabolism yielded inconsistent results in up to 42 % of the cases.
Compared to measuring uptake in absolute units, visual evaluation of skeletal scintigraphies for change in tumor metabolism yields inconsistent results in roughly one third of the cases.
