FASTMAP (Functional Analysis Software Tool for MRI and PET) is a free, open source, multi-platform tool developed in Qt/c++; visit https://www.nmr.mgh.harvard.edu/~jbm/fas... for more information. Fastmap provides an intuitive GUI for 4-dimensional imaging display, preprocessing (smoothing, alignment, reslicing, partial volume correction, …), and time-series analysis for MRI (T1, T2, ADC, DTI, fMRI) and PET (reference tissue models, SUV). Use of the Qt libraries enables multi-platform support, multi-threading, high-level access to the file system, etc. Analysis can be performed interactively or automated from the command line for many common functions.