A method for determining the information capacity of x-ray imaging scintillator detectors by means of luminescence and modulation transfer function measurements

Kandarakis, I.; Cavouras, D.; Κανελλόπουλος, Ε.; Nomicos, C.; Panayiotakis, George

doi:10.1007/bf02513261

Cited by 11 publications

(4 citation statements)

References 17 publications

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“…MTF was determined by the square wave response function (SWRF) (BARNES, 1979;ICRU, 1986;KANDARAKIS et al, 1999), employing an MTF test pattern* and film**, it is of value to mention that CdPO3CI:Mn exhibits higher spectral compatibility (matching factor) with this film (0.737) than currently used phosphors (0.52 for GdzOzS:Tb), and it is adequately high for producing highquality, low quantum noise images. The pattern-screen-film systems corresponding to each screen were irradiated with X-rays of 50 120kVp.…”

Section: Experimental Partmentioning

confidence: 99%

Integrated model for estimating phosphor signal and noise transfer characteristics on medical images: application to CdPO3Cl:Mn phosphor screens

Cavouras

Kandarakis

Panayiotakis

et al. 2002

Med. Biol. Eng. Comput.

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An integrated model describing the signal and noise transfer characteristics of the objective image quality and information content in phosphor-produced images is presented. In the context of this model, important imaging parameters, namely optical gain, modulation transfer function, noise transfer function, detective quantum efficiency and information capacity were experimentally evaluated using seven laboratory-prepared CdPO3Cl:Mn test phosphor screens of varying coating thickness. This phosphor has been previously shown to exhibit high spectral compatibility properties with the films and optical sensors used in digital imaging systems. Experiments were performed using 50-120 kVp X-rays produced by a medical X-ray unit. Results showed that, for thick screens, optical gain attained peak values close to 200 optical photons per incident X-ray at 50 kVp. The noise transfer function was higher than the modulation transfer function. For the thin screen of 21 mg cm-2, the modulation transfer function was 0.25 at 100 line pairs mm-1, and the corresponding noise transfer function was 0.4. The detection quantum efficiency peak value was 0.22 at 50 kVp. These values are within acceptable performance limits, and, given the phosphor material's high spectral compatibility and medium temporal response, CdPO3Cl:Mn could be considered for use in X-ray detectors of static radiography imaging.

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Section: Experimental Partmentioning

confidence: 99%

Integrated model for estimating phosphor signal and noise transfer characteristics on medical images: application to CdPO3Cl:Mn phosphor screens

Cavouras

Kandarakis

Panayiotakis

et al. 2002

Med. Biol. Eng. Comput.

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“…7) corresponding to each foot area was obtained using Equation 3 (see appendix for derivation). The spatial frequencies (u and v) are denoted by cycles per distance, 34 and for this analysis, since the image size (distances) were in terms of pixels, the spatial frequencies were represented by cycles per pixel.…”

Section: Calculation Of New Diagnostic Parameter Power Ratiomentioning

confidence: 99%

Optical Pedobarography for Assessing Neuropathic Feet in Diabetic Patients—A Review

Patil

Charanya

Prabhu

2002

The International Journal of Lower Extremity Wounds

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The use of optical pedobarography is presented in this article. The limitations of the analytical methods using peak pressures as a parameter for assessment of foot at risk of plantar ulcers are indicated. A new method, which takes into consideration the actual plantar pressure distribution using the power ratio PR (the ratio of high-frequency power to the total power in the walking foot pressure image distribution)and relates it to 3 levels of sensation loss is described. PR is able to detect early loss of foot sensation characterized by a loss of sensation level of 4.5 gm. The methods available in the literature for management of foot ulcers by proper footwear design, and their limitations, are discussed. A new method of individualized footwear based on matching the softness of the footwear insole with the softness of normal foot sole soft tissue (having durometer reading of 20 degrees Shore) and optimum insole thickness (12 mm) is helpful in the prevention of plantar ulcers.

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“…In 1977 and 1978, Gutzler investigated the efficiency of the phosphor under low-energy electron bombardment [4,5]. Y 2 O 2 S:Tb thin film and bulk material were synthesized and the luminescent properties and temperature dependence of cathodoluminescence were investigated [6][7][8] applications of X-ray imaging [10][11][12]. However, details of relationship between the doping concentration of terbium in yttrium oxysulfide have not been investigated.…”

Section: Introductionmentioning

confidence: 99%

The effect of terbium concentration on the luminescent properties of yttrium oxysulfide phosphor for FED application

Kang

Liu

2007

Journal of Luminescence

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A method for determining the information capacity of x-ray imaging scintillator detectors by means of luminescence and modulation transfer function measurements

Cited by 11 publications

References 17 publications

Integrated model for estimating phosphor signal and noise transfer characteristics on medical images: application to CdPO3Cl:Mn phosphor screens

Integrated model for estimating phosphor signal and noise transfer characteristics on medical images: application to CdPO3Cl:Mn phosphor screens

Optical Pedobarography for Assessing Neuropathic Feet in Diabetic Patients—A Review

The effect of terbium concentration on the luminescent properties of yttrium oxysulfide phosphor for FED application

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