Ralf Kollhoff

TL;DR: Both versions of two-dimensional ionization chamber arrays, together with the developed treatment plan verification strategy, have been found to provide a suitable and easy-to-handle quality assurance instrument for IMRT.

TL;DR: The DAVID system is presented, which is able to perform permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution while the patient is treated, and the values measured are stored as reference values after the dosimetric verification of an IMRT plan.

TL;DR: To investigate the attenuation of a carbon-fiber tabletop and a combiboard, alongside with the depth-dose profile in a solid-water phantom, transmission factors for tabletops and accessories directly interfering with the treatment beam should be measured and implemented into the treatment-planning process.

TL;DR: This work investigated and confirmed the ability of a large-area parallel-plate ionisation chamber, with a sensitive volume shaped as a flat cylinder of 81.6 mm diameter and 2 mm thickness, to perform the integration over the full lateral dose profile of narrow photon beams with side lengths up to 5 cm.

TL;DR: The unshielded Si diode PTW 60012, used for accurate measurements of the transversal dose profiles of narrow photon beams, has been investigated with regard to its linearity, photon energy dependence and spatial resolution and shows a slight supralinearity.