Carbon: highly effective and surgically precise
The biologically effective dose in the tumor can be optimized by selecting the appropriate kind of ions. Many years of research at GSI have established that carbon ions are best. The maximum biological effect coincides exactly with the maximum physical dose. These effects intensify each other synergistically so that the carbon ions damage cells very effectively at their full penetration depth within the body. In protons and lighter ions the increase in biological effectiveness is small. In heavier ions it occurs too soon and tends to damage healthy tissues overlying the tumor.
Another advantage of using carbon ions is that lateral scattering in the body is much less than with protons and lighter ions. As a result, carbon ions are better suited for irradiating deep-seated tumors selectively.