New developments in the fields of the X-ray detectors, X-ray micro/nano sources and data processing bring new possibilities for engineering practice in many applications. Nowadays it is possible to observe an object, which was difficult to image before due to limitations such as low contrast, low dynamic range, low attenuation and/or small structural dimensions. A number of compelling problems in different applications are summarized. Digital radiograms in this work are acquired using micro- and nano-focus X-ray tubes together with semiconductor digital pixelated detectors. A beam hardening correction was done for relevant radiograms and an iterative OSEM (ordered subsets) method was applied for CT reconstructions.