caliPER: A software for blood-free parametric Patlak mapping using PET/MRI input function

•caliPER is an adaptable image processing software for extracting image-derived input functions and generating parametric maps of irreversible PET tracer uptake.•Anatomical (T1- weighted/T2-weighted/time-of-flight angiography) MRI carefully aligned to PET provides a robust approach for delineation of vessels on PET, eliminating the need for serial blood sampling for input functions.•Application of caliPER in modelling glucose uptake in patients with Frontotemporal dementia, demonstrates the feasibility of absolute quantification of cerebral metabolic rate of glucose in clinical populations.