The Profile of Delay Erasure Time and Imaging Plate Sizes to Dark Noise Evaluation in Carestream Computed Radiography System

Abstract

Increasing delay time between erasure and image acquisition can lead to the appearance of dark noise on the Computed Radiography (CR) imaging plate (IP). The purpose of this study is to investigate the time delay of the last erasure that can be affected in dark noise appearance of four sizes Carestream CR’s imaging plate in Radiology Laboratory of Poltekkes Kemenkes Semarang. This study used a quantitative experimental method. Each size of IP was exposed with one of Hand, Cranium, Chest, and Abdomen anthropomorphic phantom, read on CR, and left for 0 hours, 1 hour, 3 hours, 6 hours, 9 hours, 12 hours and 24 hours to produce blank images. The blank images after post-processing were evaluated with qualitative and quantitative criteria. Qualitative criteria produced uniformity images, without ghost images artifact. While quantitative criteria were determined by the exposure index value, pixel value, and pixel value standard deviation calculated by ImageJ. The results of this study showed that all of the IPs did not pass the criteria. Dark noise appeared in 0 hours after the last erasure shown from un-uniformity images, ghost images artifact, PV, and PVSD were overpassed the standard values. Dark noise has increased the time delay between last erasure and subsequent use. The imaging plate must be erased before it acquires the next images.