COMKAT: Compartment model kinetic analysis tool

Compartment models are the basis for most physiologically based quantificat ion of nuclear medicine data. Although some software packages are available for this purpose, many are expensive, run on relatively few types of compu ters or are of limited capability, and cannot be extended because of the un availability of source code. Consequently, institutions with modeling exper tise often develop software for themselves, which has the disadvantages of lack of standardization and possible replication of effort. Therefore, gene ral-purpose compartment modeling software distributed with source code woul d be a welcome resource for the nuclear medicine community. Methods: We for mulated a mathematic framework within which compartment models containing u nimolecular and bimolecular (receptor saturation) kinetics can be described . We implemented this framework within MATLAB and call the resultant softwa re COMKAT (Compartment Model Kinetic Analysis Tool). Results: COMKAT simpli fies the process of defining and solving standard: blood flow,F-18-FDG, and receptor models as well as models of a user's own design. In particular, C OMKAT automatically defines and implements state, analytic sensitivity, and Jacobian equations. Given these, COMKAT can perform simulations in which m odel outputs are solved for specified parameter values, thereby allowing th e user to predict how sensitive data are to these parameters. In addition, COMKAT can be used to estimate values for the parameters by fitting model o utput to experimental data. COMKAT is equipped with command-line and graphi c user interfaces from which the user can access these features. Examples o f these applications are presented along with validation and performance su mmaries. Conclusion: COMKAT is-a useful software tool and is available with out cost to researchers, at www.nuclear.uhrad.com/comkat.