Magnetic enhancement of electron dose distribution in a phantom.

We have measured the effect of a 10-kG magnetic field on the dose distribution of electrons in a polystyrene phantom. Isodensity plots and depth-dose curves are presented for 22- and 28-MeV electron beams with and without the magnetic field applied. The measurements show that magnetic fields as low as 10 kG can produce a substantial modification of the absorbed dose distribution. When compared with the zero-magnetic-field distribution of the same energy, the magnetic field significantly improves the Dmax- surface dose ratio and increases the fall off in dose past the Dmax region.