Silicone rubber with lead-acid composite as alternative radiation filter in digital radiography (DR)

Abstract

Digital Radiography (DR) uses poly-energy x-rays beams, where low-energy x-rays are easily absorbed by the tissues and do not contribute to the image, therefore the low energy x-rays should be removed from the beam. The use of the radiation filter is an effective method for minimizing low-energy. The purpose of the research was to produce an alternative radiation filter for protecting organs and minimizing the dose received by patients while maintaining the quality of the image in DR examination. In this study, the radiation filters were made from Silicone Rubber-Lead Acid (SR-Pb), with the dimension of 17 x 17 x 0.6 cm3. The Pb percentage in the SR-Pb was varied from 0 to 5 wt%. To find out the feasibility of SR-Pb as a radiation filter, the dose reduction was measured using a solid-state detector (the Piranha detector, RTI Electronics, Sweden). For image quality assessment, images of the foot phantom were visually analyzed. The contrast-to-noise ratio (CNR) and signal-to-noise-ratio (SNR) values of the CDR TOR phantom with and without an SR-Pb radiation filter were measured. By the addition of Pb wt%, the foot image is still in the readable range. Analysis from the TOR CDR phantom, provided that there is no significant different between CNR and SNR value with and without SR-Pb radiation filter. The addition of Pb wt% slightly reduced the CNR and increased the SNR. SR-Pb 5 wt% decreased dose down to about 50%. This study has successfully developed the SR-Pb as an alternative radiation filter for the protection in DR examination, especially for indications that do not require an excellent low-contrast image, for example in the bone examination.