RTPFIT: A program to fit the extended general field equation to therapy unit data

✍ Scribed by J.J. Weinkam; R.A. Kolde

• Publisher: Elsevier Science
• Year: 1973
• Weight: 854 KB
• Volume: 3
• Category: Article
• ISSN: 0010-468X
• DOI: 10.1016/0010-468x(73)90007-x

✦ Synopsis

The first formula for computing dose distribution was developed by Sterling et al. for the Eldorado A therapy unit at 80 cm ssd. This formula later evolved into the General Field Equation which was applicable over the entire range of source skin distances. Recently, this equation has been extended to fit the dose distributions of a wide variety of therapy units, including cobalt units, linear accelerators, and betatrons.

Fitting the Extended General Field Equation to dose data is a complex task involving the use of nonlinear regression. This paper describes a software package to perform this task, The system is implemented on an IBM 360.

The procedure can readily accept either directly measured dose data or digitized data from manufacturer-supplied isodose charts.

In addition to the basic task of fitting the equation to the dose data, the program performs a comparison of the computed and observed dose values and an analysis of the error distribution.