Plotting PET TACs
All spreadsheet programs (MS Excel, OpenOffice, ...) can be used to plot the (x,y) curve data.
Files of TAC data can be imported to spreadsheet programs as ASCII text files, but to prevent
problems with formatting and decimal separator,
it is recommended that TAC files are first converted into HTML
table or CSV format: program tacformat can be used to
convert data files into XML or CSV format, entering
appropriate options to deal with decimal and column separators, when necessary;
at least MS Excel can then correctly import these
-mid will save the data with middle frame time.
Alternatively, program tac2xml can save data from several TAC files into a single Excel compatible XML file, with the contents of each TAC file in its own sheet. Prior to this, tacjoin can be used to combine TAC files. Additionally, program dft2html can be used to convert data files into HTML table format. These can then be opened in spreadsheet programs (also drag-and-drop works).
Simple plots can be easily made with spreadsheet programs, but use
Origin for drawing publication quality graphics.
Turku PET Centre and University of Turku have licences to Origin, please ask IT group to install
it to your PC. User's manual is available in
PET Centre Intranet > Instructions > Origin75.
Spreadsheet data can be copy-pasted from Excel into Origin worksheet.
Plotting TACs in SVG format
PET curves can be quickly drawn in SVG files and then the saved SVG files can be viewed or printed with any up-to-date web browser, or edited further, converted to other formats, or combined into composite image as explained here.
When a model or mathematical function is fitted to the time-activity curves, it is necessary to check by eye the goodness of the fit. Most in-house analysis programs can optionally save the measured data points and fitted curves in SVG format.
Alternatively, fitted curve data can be saved as data file (optionally) by most analysis programs. When mathematical functions are fitted to data and fitted parameters are saved in *.fit files, the fitted TAC can later be computed and saved in TAC format using fit2dat.
Fitted curves saved as TAC files can then be imported to spreadsheet program as above. Program tac2svg can be used to plot both the measured data and fitted curve(s) in the same graph.
Viewing PET frames
If TAC data needs to be plotted with bars representing the PET frames, program tac4frpl can be used to transform TAC files into versions that contain both frame start and and end times in the x axis. These can then be easily plotted with previously mentioned programs.
- SVG in TPC
- Regional TAC data
- Analysis models for regional TACs
- Fitting input TACs
- Fitting plasma parent fractions
Adams C: Learning Python Data Visualization. Packt Publishing, 2014. ISBN 978-1-78355-333-4.
Devert A: matplotlib Plotting Cookbook. Packt Publishing, 2014. ISBN 978-1-84951-326-5.
Janert PK: Gnuplot in Action - Understanding Data with Graphs. Manning Publications Co, 2010. ISBN 978-1-933988-39-9.
Phillips L: gnuplot Cookbook. Packt Publishing, 2012. ISBN 978-1-84951-724-9.
Rahlf T: Data Visualization with R - 100 Examples. Springer, 2017. doi: 10.1007/978-3-319-49751-8.
Updated at: 2020-05-26
Created at: 2010-08-11
Written by: Vesa Oikonen