Arterial input function

Each data-point in the AIF curve represents a measurement of tracer-concentration from an artery obtained from each of these image time-frame acquired over time, with external corrections applied to it.

[citation needed] A population-based input function generally relies on the dataset previously obtained by other researchers in a specific set of populations, and average values are used.

In a neuroinflammation study, the author using a population-based input function in healthy volunteers and liver-transplanted patients imaged using [18F]GE-180 PET.

[citation needed] However, Blake et al.[16] derived a semi-population based method from healthy postmenopausal women imaged using [18F]NaF for bone studies[16] based on the observation that the later part of the arterial input function can be constructed from the venous blood samples, as the venous and arterial blood concentration of tracer is equal 30 minutes after the injection.

These errors are corrected using late venous blood samples,[4][10] and the resulting curve is called an arterial input function (AIF).