However, it should be pointed out that μPET imaging in mice still has major limitations with regards to spatial resolution of currently available μPET scanners, attenuation correction and correct quantification, as well as anesthesia-induced changes of radiotracer uptake.
Correction of background vertical shift of the amplification curve is the prerequisite for the correct quantification.
With the use of ordered subset expectation maximization (OSEM) reconstruction and adequate correction methods, quantification of SPECT images is currently viable and attractive [4], and it enables quantification of gamma-emitting radionuclides, like 111In.
In this paper, a multielement procedure for high spatial resolution analysis of ferromanganese concretions using LA-ICP-MS is described, with emphasis on the optimisation of measuring parameters, internal standard correction and quantification by external calibration against matrix-matched standards.
Notably, after log transformation and batch effect correction, the quantification method even explains slightly more of the variation than the tissue, whereas all other factors are essentially uninformative.
Image reconstructions included all routine corrections required for quantification, such as scatter correction, attenuation correction, normalization, and dead time and decay corrections.
In order to assess metabolite recovery from the sample, internal standards are often spiked in the extraction buffer, functioning also as a correction factor for quantification [37] (Figure 1B).
Since PET/MRI holds the promise for integrated and potentially improved diagnostic accuracy in prostate cancer by combining the high soft tissue contrast of MRI with the characteristics of new tracers (e.g., PMSA), it is obvious and mandatory to have reliable attenuation correction and signal quantification for those procedures.
Deep inspiration chest CT scans should not be used for attenuation correction when PET quantification is required or intended.
