Stephan Kloeck

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PURPOSE To investigate dosimetric characteristics of a new linear accelerator designed to deliver flattened, as well as flattening filter-free (FFF), beams. To evaluate the accuracy of beam modeling under physical conditions using an anisotropic analytical algorithm. METHODS AND MATERIALS Dosimetric data including depth dose curves, profiles, surface(More)
PURPOSE To evaluate the potential usage of flattening filter-free (FFF) photon beams in the treatment of prostate cancer. METHODS AND MATERIALS Volumetric-modulated arc therapy (VMAT) treatment planning was performed for 7 patients using TrueBeam(®) linear accelerator and photon beams with (X6, X10) and without (X6FFF, X10FFF) flattening filter.(More)
PURPOSE To investigate the clinical application of flattening filter free (FFF) beams at maximum dose rate for stereotactic body radiotherapy (SBRT). METHODS AND MATERIALS Patients with tumors in the lung or abdomen were subjected to SBRT using 6 MV FFF or 10 MV FFF beams. For each patient, three plans were calculated using 6 MV flattened, 6 MV FFF, and(More)
PURPOSE To evaluate PTV margins for hypofractionated IGRT of prostate comparing kV/kV imaging or CBCT. PATIENTS AND METHODS Between 2009 and 2012, 20 patients with low- (LR), intermediate- (IR) and high-risk (HR) prostate cancer were treated with VMAT in supine position with fiducial markers (FM), endorectal balloon (ERB) and full bladder. CBCT's and(More)
OBJECTIVE Quality assurance data from five centres were analysed to assess the reliability of RapidArc radiotherapy delivery in terms of machine and dosimetric performance. METHODS A large group of patients was treated with RapidArc radiotherapy and treatment data recorded. Machine quality assurance was performed according to Ling et al (Int J Radiat(More)
PURPOSE Outcome in locoregionally advanced laryngeal carcinoma and hypopharyngeal carcinoma after conventional radiation techniques is known for modest disease control and considerable late toxicity. Considering the lack of standardization in prescription dose for intensity-modulated radiotherapy (IMRT), we aimed to compare the results after our methods of(More)
PURPOSE To perform comparative planning for intensity-modulated radiotherapy (IMRT) and proton therapy (PT) for malignant pleural mesothelioma after radical surgery. METHODS AND MATERIALS Eight patients treated with IMRT after extrapleural pleuropneumonectomy (EPP) were replanned for PT, comparing dose homogeneity, target volume coverage, and mean and(More)
PURPOSE To compare contribution and accuracy of delivery for two flattening filter free (FFF) beams of the nominal energy 6 and 10 MV and a 6 MV flattened beam for early stage lung cancer. METHODS For each of 11 patients with stage I nonsmall cell lung cancer three volumetric modulated arc therapy plans were prepared utilizing a 6 MV flattened photon beam(More)
PURPOSE Tumor motion increases safety margins around the clinical target volume and leads to an increased dose to the surrounding healthy tissue. The authors have developed and evaluated a one-dimensional treatment couch tracking system to counter steer respiratory tumor motion. Three different motion detection sensors with different lag times were(More)
Recently, there has been an increased interest in flattening-filter-free (FFF) linear accelerators. Removal of the filter results in available dose rates up to 24 Gy min(-1) (for nominal energy 10 MV in depth of maximum dose, a source-surface distance of 100 cm and a field size of 10×10 cm2). To guarantee accurate relative and reference dosimetry for the(More)