Logan_tstar: Tstar Finder: Logan Plot

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

Tstar Finder: Logan Plot

Description

Function to identify where t* is for the Logan Plot.

Usage

Logan_tstar(
  t_tac,
  lowroi,
  medroi,
  highroi,
  input,
  filename = NULL,
  inpshift = 0,
  vB = 0.05,
  frameStartEnd = NULL,
  gridbreaks = 2
)

Arguments

t_tac	Numeric vector of times for each frame in minutes. We use the time halfway through the frame as well as a zero. If a time zero frame is not included, it will be added.
lowroi	Numeric vector of radioactivity concentrations in a target tissue for each frame. This should be from a ROI with low binding.
medroi	Numeric vector of radioactivity concentrations in a target tissue for each frame. This should be from a ROI with medium binding.
highroi	Numeric vector of radioactivity concentrations in a target tissue for each frame. This should be from a ROI with high binding.
input	Data frame containing the blood, plasma, and parent fraction concentrations over time. This can be generated using the blood_interp function.
filename	The name of the output image: filename_Logan.jpeg
inpshift	Optional. The number of minutes by which to shift the timing of the input data frame forwards or backwards. If not specified, this will be set to 0. This can be fitted using 1TCM or 2TCM.
vB	Optional. The blood volume fraction. If not specified, this will be ignored and assumed to be 0 prior to parameter estimation using the following equation: C_{T}(t) = \frac{C_{Measured}(t) - vB\times C_{B}(t)}{1-vB}
frameStartEnd	Optional: This allows one to specify the beginning and final frame to use for modelling, e.g. c(1,20). This is to assess time stability.
gridbreaks	Optional. The size of the grid in the plots. Default: 2.

Value

Saves a jpeg of the plots as filename_Logan.jpeg

Author(s)

Granville J Matheson, [e-mail]

Examples

## Not run: 
Logan_tstar(t_tac, lowroi, medroi, highroi, input,
  filename = "demonstration",
  inpshift = onetcmout$par$inpshift, vB = 0.05, gridbreaks = 4
)

## End(Not run)

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