Recent advances in X-ray photoconductors for direct conversion X-ray image detectors

Recent research on flat panel X-ray image detectors has shown their potential for replacing existing X-ray film/screen cassettes and capturing X-ray images electronically, thus enabling the clinical transition to digital radiography. The present work examines the imaging properties of a number of potential X-ray photoconductors for these new X-ray image detectors. The X-ray sensitivity is discussed in terms of the absorption efficiency, electron–hole pair creation energy (ionization energy), and charge transport and trapping limited collection efficiency. X-ray photoconductor properties of various semiconductors are compared and critically discussed with special attention to stabilized a-Se and HgI2, currently the most promising materials.