metab_invgamma: Fit the Inverted Gamma Function for Modelling Parent...

In mathesong/kinfitr: Kinetic Modelling of PET Time Activity Curves

Fit the Inverted Gamma Function for Modelling Parent Fraction.

Description

This function fits the inverted integrated gamma function to parent fraction data.

Usage

metab_invgamma(
  time,
  parentFraction,
  fit_ppf0 = FALSE,
  fit_delay = FALSE,
  lower = list(a = 0.8, b = 0.3, c = 0, d = 0, delay = -30),
  upper = list(a = 1.1, b = 3, c = 20, d = 1e+06, delay = 30),
  multstart_lower = NULL,
  multstart_upper = NULL,
  multstart_iter = 1000
)

Arguments

time	Time in seconds.
parentFraction	Measured values of parent fraction.
fit_ppf0	Should the starting plasma parent fraction be fitted? Otherwise, it is set to 1. Defaults to FALSE.
fit_delay	Should the delay of the plasma parent fraction be fitted? Otherwise, it is set to 0. Defaults to FALSE.
lower	Named list of the lower limits.
upper	Named list of the upper limits.
multstart_lower	Named list of the lower starting limits.
multstart_upper	Named list of the upper starting limits.
multstart_iter	Number of fits to perform before deciding on an optimal.

Value

An nls fit object.

References

Finnema SJ, Nabulsi NB, Mercier J, Lin SF, Chen MK, Matuskey D, Gallezot JD, Henry S, Hannestad J, Huang Y, Carson RE. Kinetic evaluation and test–retest reproducibility of [11C] UCB-J, a novel radioligand for positron emission tomography imaging of synaptic vesicle glycoprotein 2A in humans. Journal of Cerebral Blood Flow & Metabolism. 2018 Nov;38(11):2041-52.

Examples

## Not run: 
pf <- bd_getdata(blooddata, output = "parentFraction")
metab_invgamma(pf$time, pf$parentFraction)

## End(Not run)

mathesong/kinfitr documentation built on Jan. 15, 2024, 11:07 p.m.