The study of collimation effect of low energy X-ray for radiographic imaging

Abstract

Radiographic imaging is the preferred method in the medical and industrial field because it does not permanently alter the diagnosed or inspected object’s structure, nonintrusive, nor cause permanent damage. The present work aims to provide guidelines to improve radiographic image quality by optimizing X-ray filtration parameters, which do not involve detector replacement or modification to the existing system. The image quality was quantified using the calibrated contrast noise ratio (CNR) of the sample images obtained using a low energy X-ray source of 40 kV at the Malaysian Nuclear Agency. A sample comprising of low and high Z materials was used to represent contrabands in a baggage carrier. CNR of the images is observed by varying X-ray applied current (1 mA - 2 mA) and exposure time (1 s - 100 s). Five collimator slits with different openings (5 mm - 15 mm) were prepared and tested at different speeds (0.40 mm/s - 5.71 mm/s). From observations, X-ray filtration improves image quality at specific optimal settings of 40 kV anode voltage, 0.40 mm/s scanning speed, and 15 mm slit width opening. This finding is specifically for this system. Different system may have different response in terms of slit size, scanning speed, and other radiation parameters. This work serves as a reference for improving radiographic image quality from low to high Xray energies in medical and industrial applications.