Aims and objectives The main objective in digital radiography is to obtain appropriate image quality that is sufficient for precise diagnosis with radiation dose to the patient as low as possible (ALARP)[1]. This goal is demonstrated by the radiation protection principle (ALARP) which must be performed to control radiation dose to patients during the radiography examinations [2]. Various imaging techniques\protocols have been utilised in chest radiography. In addition, various X-ray image receptors and X-ray machines from a range of manufacturers are available and their performance could be different [3-5]. Consequently, these factors could lead to a variation in image quality and radiation dose between X-ray units for the same radiography examination. View article