Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

ST: Fachverband Strahlen- und Medizinphysik

ST 5: Imaging with Ionizing Radiation I

ST 5.1: Talk

Thursday, March 17, 2011, 10:00–10:15, POT 112

Simulation of grating-based X-ray phase contrast tomography — •Klaus Achterhold, Julia Herzen, and Franz Pfeiffer — Department of Physics (E17) and Institute of Medical Engineering (IMETUM), Technische Universität München, Germany

Grating-based X-ray phase contrast tomography proved to achieve better contrast in soft tissue than conventional X-ray absorption. The real part of the refractive index of the tissue results in a slight deflection of the X-rays. These tiny angles of approximately 20 nrad can be detected by a combination of a phase and absorption gratings. With an absorption grating near the anode of a conventional X-ray tube the method is applicable as part of a medical device. Hence X-ray phase contrast can be used in the detection of soft tissue pathologies e.g. breast tumor in mammography. The application in the clinics demands the lowest dose for the patient though the best contrast to noise ratio (CNR). To accomplish this, we simulated the imaging varying the height and pitch of the gratings for a given power and spectrum of the X-ray tube. Source, detector and grating distances were under the constraint of the dimensions of a putative computer tomograph. Optimal combinations where found for maximal CNR. The results will be important for the design and implementation of the X-ray phase contrast method in commercial CT devices.