Methods to calculate the lens efficiency in optically coupled CCD x-ray imaging systems

Hong Liu, Andrew Karellas, Lisa J. Harris, Carl J. D'orsi

Research output: Contribution to journalLetterpeer-review

50 Scopus citations


In lens-coupled CCD x-ray imaging, the lens efficiency is of critical importance for attaining an x-ray quantum-noise-limited system. However, the equations and the associated parameters of this process have not always been used properly in some of the literature. This can result in the incorrect estimation of the signal-to-noise ratio (SNR). In practice, it is found more convenient to use lens-coupling efficiency equations which assume that the scintillating screen is an extended Lam-bertian source, since the number of light photons emerging from various scintillating screens has been measured and reported by several investigators. This communication examines several of the most common types of lens-coupling efficiency equations and explains how to use them correctly with other parameters to calculate the SNR of a lens-coupled CCD x-ray imaging system.

Original languageEnglish (US)
Pages (from-to)1193-1195
Number of pages3
JournalMedical physics
Issue number7
StatePublished - Jul 1994


  • CCD imaging
  • lens efficiency
  • signal-to-noise ratio

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging


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