Modified Tissue‐Phantom Ratios are an analogous quantity to Tissue‐Air Ratios for beam energies greater than 2MV. Direct measurement of Modified Tissue‐Phantom Ratios is a tedious and error prone process, and may be avoided by applying an unfolding procedure to Central Axis Depth Dose Data. The method requires that a small range of Modified Tissue‐Phantom Ratios be obtained by direct measurement.
Summary
A method for generating MTPR data from PDD has been described. Results of the application of the method to an 8MV X‐ray beam have been tabulated.
The principal areas in which experimental errors exist have been indicated, and their magnitude given as a between classes error histogram.
The method of pivotal unfolding is recommended as an accurate and time saving procedure for the generation of Modified Tissue‐Phantom Ratios.