EGS Application - The Human Body
The experiment described below shows how accurately EGS can model features within the human body. This is an excerpt from the article entitled "EGS, A Technology Spinoff to Medicine" from the Beam Line, Spring 1991 issue.
Using a 20-MeV accelerator, scientists at the National Research Council of Canada (NRCC) placed small cylinders of aluminum and air within a large tank of water and irradiated them with electrons (see picture below ).
Measurements were made at various locations in the water, particularly near the surface of the cylinder, and computer simulations were performed using EGS. In the results presented in the figures below, the smooth curves represent the measured data and the histograms are EGS calculations.
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A typical depth-dose curve in a homogenous "phantom" of water -- i.e., containing no voids or solid materials -- is shown in the figure at left. The other two curves demonstrate how an aluminum cylinder attenuates, and an air cylinder enhances, the dose along the central axis within the phantom. |
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The radial dose profile at various locations downbeam from the air cylinder was also measured and the results are shown in the final set of figures at at left. Clearly the dose perturbations caused by discontinuities are well predicted by EGS, lending considerable confidence to the ability of the program to simulate the passage of electrons through the human body. |
