Beam characteristics in two different proton uniform scanning systems: a side-by-side comparison.

Purpose: To compare clinically relevant dosimetric characteristics of proton therapy fields produced by two uniform scanning systems that have a number of similar hardware components but employ different techniques of beam spreading.

Methods: This work compares two technologically distinct systems implementing a method of uniform scanning and layer stacking that has been developed independently at Indiana University (IU) and by Ion Beam Applications, S. A.