THE HIT GANTRY: FROM COMMISSIONING TO OPERATION

Abstract

The patient treatment at the first 360 ◦ raster scanning heavy ion gantry of the Heidelberg Ion Therapy Facility (HIT) started in October 2012 using carbon ion and proton beams. HIT is the first dedicated proton and carbon cancer therapy facility in Europe. It uses full 3D intensity controlled raster scanning dose delivery method of pencil beams. The ion energy ranges from 48 up to 430 MeV/u (ion penetration depths of 20 to 300 mm in water). Beams are provided by a linac-synchrotron-system to four high energy beam lines: 2 horizontal patient treatment rooms; 1 horizontal experimental cave for quality assurance, development, and research work; and the heavy ion gantry. From the first commissioning the libraries of carbon and proton pencil beams at the gantry had been established with the whole variety of ion beam properties, i. e. 255 energy steps, 4 beam foci, 360 ◦ , and 10 intensities (10 6 –10 10 /spill) regarding the iso-centric beam. This paper reflects the impact of the subsequent preclinical testing including beam size/position, and dose measurements within the irradiation field of 20 × 20 cm 2 on the further improvement of the ion optical settings of the gantry high energy transfer line.