1. NAME AND TITLE

REPC: Estimation of Nuclear Reaction Effects in Proton-Tissue-Dose Calculations.

2. CONTRIBUTOR

NASA Langley Research Center, Hampton, Virginia.

3. CODING LANGUAGE AND COMPUTER

Fortran V; CYBER.

4. NATURE OF PROBLEM SOLVED

REPC reviews calculational methods for the estimation of dose from external proton exposure of arbitrary convex bodies and presents the necessary information for the estimation of dose in soft tissue. The effects of nuclear reactions, especially in relation to the dose equivalent, are retained. REPC subroutines can be used to convert existing computer programs which neglect nuclear reaction effects to include them.

5. METHOD OF SOLUTION

REPC contains a general method for the estimation of dose in arbitrary convex geometry in terms of dose conversion factors in slab geometry. These dose conversion factors for protons in tissue are then represented using buildup factors. A parametric form for the buildup factors is presented. The values for the parameters are derived from Monte Carlo calculations of various authors. All necessary information for estimation of dose and dose equivalent for proton irradiation of convex objects of arbitrary shape is contained in REPC. This method has the advantage that existing proton dose calculations in which nuclear reactions are neglected can be directly converted by substitution of the dose conversion factors presented in REPC.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running times for REPC.

8. COMPUTER HARDWARE REQUIREMENTS

REPC was designed for the CYBER computer.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

J. W. Wilson and G. S. Khandelwal, "Computer Subroutines for the Estimation of Nuclear Reaction Effects in Proton-Tissue-Dose Calculations," NASA TM X-3388 (June 1976).

J. W. Wilson and G. S. Khandelwal, "Proton-Tissue-Dose Buildup Factors," Health Physics Vol. 31 (August 1976) 115-118.

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code.

12. DATE OF ABSTRACT

February 1983.