Mobile chest radiography remains the most appropriate test for critical care patients with cardiorespiratory changes and with patients who have chest tubes and lines as a monitoring tool, and to detect complications related to their use. However, one of the most frequent issues recognized radiographically with patients in critical care is chest tubes and lines malposition. This can be related to technical quality reasons which can affect their appearance in the chest radiography. This research considers how the technical quality of the ICU/CCU chest radiography can impact upon the appearance of chest tubes/lines and how that appearance can impact on the decision making. Results show that the methods used in the chest phantom experiment to estimate the degree of angulation have a large effect upon the appearance of anatomical structures, but it does not have a particularly large effect upon the apparent changes of tube/line position central venous catheter and endotracheal tube (CVC, ETT). The study also shows that there was a little difference between the two image processing algorithms, apart from the visualisation of sharp reproduction of the trachea and proximal bronchi, which was significantly better using the standard algorithm compared to the inverted algorithm. The two methods used to estimate the degree of angulation and the apparent position of the CVC/ETT on 17 mobile chest radiographs provide limited useful information to the image interpreter in estimating the degree of angulation and degree of malpositioning of the tube and line.