Mask collimation meets high-efficient data acquisition: A novel design of a low-dose-CT-scanner for breast-imaging.

A novel designed x-ray CT scanning geometry is proposed. Composed of a specially designed tungsten collimation mask and a flat panel detector, which is placed inside the mask, this scanning geometry provides high efficient data acquisition allowing dose reduction potential by a factor of two. In recent years a first prototype of the CTDOR geometry (CT with Dual Optimal Reading) has been evaluated. It consisted of a discontinuous ring of detectors fixated on X-Ray absorbing material. The source and an outer detector were mounted on a gantry rotating around the inner static detector and the patient. Despite many drawbacks, resulting images have shown promising potential of dual reading. Based on those results, the present work presents further development and improvement of the recommended scanner geometry. The main idea consists of collimating the X-ray beam through a specially designed shielding mask thereby reducing radiation dose and structuring data without compromising image quality. An especially developed high precision laser-beam cutting process assures an accurate mask crafting with tungsten shielding and window sizes of 300μm. Additionally, simulation data were obtained with Monte Carlo calculations to test the dose reduction potential of the scanning device. Retaining advantages of the CTDOR geometry such as 3D-capability, built-in capacity of scatter correction and radiation structuring, a high-precision manufactured collimation mask of novel designed CT-scanner enables high resolution images for breast-imaging in low energy ranges