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ST: Fachverband Strahlen- und Medizinphysik

ST 6: Heavy Ion Therapy and Related Basic Research II

ST 6.2: Vortrag

Dienstag, 26. Februar 2008, 11:45–12:00, H 2033

Evaluation of motion tracking by cell survival measurements — •Alexander Schmidt¹, Christoph Bert¹, Nami Saito¹, Naved Chaudhri¹, Cläre von Neubeck¹, Gheorghe Iancu¹, Dieter Schardt¹, and Eike Rietzel^1,2 — ¹GSI, Abt. Biophysik, Planckstr. 1, 64291 Darmstadt, Germany — ²Siemens Medical Solutions, Particle Therapy, Hofmannstr. 26, 91052 Erlangen, Germany

At GSI patients with stationary tumors are treated with a rasterscanned carbon ion beam. For moving targets interplay possibly deteriorates the dose distribution because target motion and scanner motion interfere. Several motion mitigation techniques are proposed to solve this problem (see Bert et al., this conference). We use a fully integrated 3D online motion compensation system (see Saito et al., this conference) to track target motion of phantoms which includes adaptation of the Bragg peak position.

To validate motion tracking with biological systems we conducted a series of repetitive experiments with hamster cells grown in wellplates. The wellplates were placed on a sliding table to induce lateral as well as longitudinal motion. Irradiations were performed with stationary wellplates and by tracking moving wellplates. Multiple samples were irradiated to gain statistics.

As a result, we observed no significant difference in cell survival between the motion compensated measurements in comparison to a stationary reference irradiation. We conclude that our motion compensation system allows correct delivery of the biologically effective dose to moving phantoms.