dvr {tacmagic}

Distribution volume ratio (DVR) for one or more ROIs

Description

This calculates the DVR using the non-invasive reference Logan method for all TACs in a supplied tac file. It uses DVR_ref_Logan if a target ROI is specified, otherwise will calculate DVR for all ROIs with DVR_ref_all_Logan()

Usage

dvr(
  tac,
  model = "logan",
  target = NULL,
  ref,
  k2prime,
  t_star,
  error = 0.1,
  method = "trapz"
)

Arguments

tac

The time-activity curve data from load_tac() or tac_roi()

model

Only model currently available is "logan"

target

Optional - otherwise will calculate DVR for all regions

ref

Required – The reference region, e.g. "cerebellum"

k2prime

Required – A fixed value for k2' must be specified (e.g. 0.2)

t_star

Required – If 0, t* will be calculated using find_t_star()

error

For find_t_star()

method

Method of integration, "trapz" or "integrate"

Details

For other model parameters, directly call DVR_ref_Logan().

Value

Data frame with calculated DVRs

References

Logan, J., Fowler, J. S., Volkow, N. D., Wang, G.-J., Ding, Y.-S., & Alexoff, D. L. (1996). Distribution Volume Ratios without Blood Sampling from Graphical Analysis of PET Data. Journal of Cerebral Blood Flow & Metabolism, 16(5), 834-840. https://doi.org/10.1097/00004647-199609000-00008

See Also

Other Logan plot functions: DVR_all_ref_Logan(), DVR_ref_Logan(), plot.ref_Logan()

Examples

f <- system.file("extdata", "AD06.tac", package="tacmagic")
fv <- system.file("extdata", "AD06_TAC.voistat", package="tacmagic")
AD06_tac <- load_tac(f, format="PMOD")
AD06_volume <- load_vol(fv, format="voistat")
AD06 <- tac_roi(tac=AD06_tac, volumes=AD06_volume, ROI_def=roi_ham_pib(),  
                merge=FALSE, PVC=FALSE)  

AD06_DVRs <- dvr(AD06, ref="cerebellum", k2prime=0.2, t_star=23)

AD06_DVR <- dvr(AD06, target="frontal", ref="cerebellum", 
             k2prime=0.2, t_star=23)