A challenge for high-precision radiation therapy: The case for photons

The sophistication of Hadron facilities led to major technical and conceptu al advances in the treatment immobilization, reproducability, planning and execution. Some of these developments have had a pivotal impact on conventi onal treatments, which can now approach the dose localization advantage of protons in the majority of clinical situations. While the biological advant ages of neutrons may finally be combined with excellent dose localization i n Heavy Ion Facilities, modern surgical or systemic treatment methods may r educe high LET advantages. Clinical trials still need to define the relativ e merits of these approaches in their most modern implantation. The advanta ge gap has certainly been narrowed by recent developments in conventional t herapy.