Particle Beam Therapy: A Quick View

Abstract

In recent years, proton and heavy ion therapy have increasingly interested both researchers and clinicians due to their desirable characteristics of definite range, high LET beams and Bragg peak. These heavy charged particles continuously interact with their travelling medium and deposit energy in large clusters, the size of which increases with decreasing energy of beam, as they traverse through a medium until they come to a stop. These beams deposit the greatest amount of energy near the end of their range. As a result, the beam profile has very typical features of definite range and rapid fall-off. The peak of highest dose is called the Bragg peak. The biggest disadvantage of proton beams is the very narrow range of the Bragg peak (in mm), which is insufficient to encompass deep-seated tumours. This requires the Bragg peak to be extended over a larger volume and is called spread-out Bragg peak which has a lower dose at the entrance, a flat region of spread-out peak and a rapid dose fall-off at the end of its range.