@CONFERENCE\{IMM2007-05372,
    author       = "B. B{\"{o}}dvarsson and L. K. Hansen and G. M. Knudsen and C. Svarer",
    title        = "Estimation of time activity curves from positron emission tomography with {NMF} and Bootstrap",
    year         = "2007",
    keywords     = "{NMF,} Bootstrap, {PET}",
    pages        = "S101",
    booktitle    = "Human Brain Mapping 2007 Chicago",
    volume       = "36",
    series       = "",
    editor       = "NeuroImage",
    publisher    = "",
    organization = "",
    address      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/5372-full.html",
    abstract     = "Measurement of the cerebral input function in terms of the arterial plasma input time activity curve (TAC) is required for assessment and validation of the quantification of receptor binding parameters on the basis of dynamic positron emission tomography (PET) images and kinetic models [4]. A vascular input {TAC} can be estimated using non-negative matrix factorization (NMF) [1] [2]. The scaling of the estimated {TAC} is found by making assumptions on the mixing matrix in the {NMF} model. 

To estimate how precise the estimated curve are, a resampling scheme called Bootstrap[3] is applied to the {NMF} estimated TACs. The Bootstrap gives error bars on the curves and this can be used to validate the precision of the solution. Correlation with the sampled {TAC} is used to estimate the number of components in the {NMF}."
}