The Comparison of Treatment Plans.

Abstract

Abstract The comparison of plans, once done by looking from one isodose plot to another, has become in hyper-dimensional planning a sophisticated matter. I have described here a number of tools that support plan evaluation and comparison, namely: 1.1. Side-by-side display of dose distributions: using color-wash to represent dose; displays on any section, transverse, sagittal, coronal, oblique; ostensive (mouse-driven cursor) interrogation of dose at a point; pan and zoom to highlight a specified volume of interest. 2.2. Dose-volume histograms: cumulative and (optionally) differential; with superposed constraint points. 3.3. Dose statistics: minimum, mean, maximum dose to a volume of interest; minimum dose received by a specified proportion of a VOI; proportion of a VOI which receives at least a specified dose; numerical score based on deviation from specified dose or dose-volume constraint. 4.4. Biophysical models: tumor control probability; normal tissue control probability. The greater complexity that this tool kit implies has, of course, its downside: although the clinician has much more useful information at his or her fingertips, it can take longer to use it. For this reason I have emphasized here the importance of speed and inter-activity in the programs and of tools to help users in the evaluation process. These are becoming increasingly available in the new generation of treatment-planning programs; pressure from the consumer is needed to keep researchers on their toes and manufacturers responsive!