Computer programs for the radioactive microsphere technique. Determination of regional blood flows and other haemodynamic variables in different experimental circumstances.

Computer programs in FORTRAN IV have been designed to calculate regional blood flow values from injections of gamma radiation-emitting radioactive microspheres. The first program PRSO constitutes a file containing the names of organs, organ groups and systemic haemodynamic variables and data about the isotopes in use. The second program PRSI transfers the data of the particular experiment concerning protocol, systemic haemodynamic variables, organ weights, number of vials belonging to each organ and the radioactivity from each vial into a data file that is subsequently analyzed by the third program PRSII. One of 5 data conditions which later directs calculations in PRSII is determined by PRSI. PRSII deducts background radioactivity, decomposes the spectrum from the mixture of up to 6 nuclides using the "stripping' method, and corrects for isotope decay during the counting period. Depending upon the data condition, PRSII calculates one or more of the following variables: (i) cardiac output (CO); (ii) the distribution of CO; (iii) regional blood flow values and tissue vascular resistances; (iv) the distribution of blood flow within an arterial bed; (v) arteriovenous anastomotic blood flow; (vi) some specified systemic haemodynamic variables; and (vii) blood flow ratios. The systemic and regional haemodynamic data belonging to experiments are saved for later statistical analyses (e.g., mean, standard error of the variables, changes from the base line, comparison between two groups of experiments) by other programs. PRSO, PRSI and PRSII can be operated by investigators with little or no special training in computer use.