Physical image quality evaluation of a CCD-based x-ray image intensifier digital fluorography system for cardiac applications

Abstract

An evaluation of the physical imaging performance of a prototype CCD-based TV camera (XTV16) cardiac Digital Fluorography system is presented. A tube-based TV camera (XTV1 1) operates in parallel, via a 50% mirror, allowing a direct comparison between the two different TV image recording technologies. The MTF, Noise Power Density (NPD) spectrum and the DQE of the system have been determined. The NPD analysis has been completed in both horizontal and vertical directions and, for completeness, a two dimensional noise analysis of the system has also been carried out. An audit of the main sources of noise in the systems is presented. The effectiveness of image corrections in minimising systematic noise due to the CCD camera is demonstrated. The DQE spectra of both systems at zero frequency are X-ray quantum noise limited and they are both operating dose efficiently. The DQE spectrum in the horizontal direction of the XTV16 at high spatial frequencies is shown to be superior to that of the XTV 1 1 which may translate to improved rendition of small features in clinical images.The CCD camera system described here is now used in the Cardio-Vascular systems of a major european company.

Solid‐state fluoroscopic imager for high‐resolution angiography: Physical characteristics of an 8 cm×8 cm experimental prototype

“…In image-intensifier/video pickup tube-based systems image lag is signal dependent, 18,46,47 which makes it difficult to incorporate temporal filtering algorithms. The DQE performance of the imager is comparable with that achieved by image intensifier based fluoroscopic systems at low spatial frequencies [13][14][15][16]18,20 and show a significant improvement at mid-to high-spatial frequencies. 14 -16,18 The limiting resolution of this prototype imager is either comparable [19][20][21]48 or slightly better 22 than that reported with amorphous silicon-based flat-panel fluoroscopy devices depending on the implemented pixel pitch and the scintillator used.…”

“…Such objective measures detailing the performance of imaging systems developed for mammography [1][2][3][4] and radiography [5][6][7][8][9][10][11][12] have been reported. Similar measures of image quality for fluoroscopic imaging systems based on image intensifiers, [13][14][15][16][17] amorphous silicon, 18 -22 amorphous selenium, 7,[23][24][25][26] and CCDs coupled to scintillator using fiberoptic tapers 27,28 have also been reported.…”

“…The measured 10% presampling MTF of 3.6 cy/mm of this prototype imager was in general better than x-ray image intensifier-based systems ͑XRII͒ operating in the nonzoom mode and coupled to video pickup tubes 15,16 or chargecoupled devices. 14 -17,20 However, when XRII-based systems are operated in the zoom mode and depending on the video capture device used, 20,45 10% MTF comparable to that with this prototype imager is observed.…”