Light Diffusion in Photographic Layers: Its Influence on Sensitivity and Modulation Transfer*

Belder, Marijke De; Kerf, J. De; Jespers, J.; Verbrugghe, R. G. L.

doi:10.1364/josa.55.001261

Cited by 24 publications

(7 citation statements)

References 1 publication

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“…11 However, the experimental determination of optical parameters, s and a , in the near-infrared region has been scarce and results vary significantly, for example, for the skin tissues. 5,8,10 Two values of s and two beam profiles of F͑͒ have been used in our simulations to investigate the dependence of the light propagation on these parameters. For results presented in this paper, we chose s ϭ 10 ͑mm Ϫ1 ͒ or 5 ͑mm Ϫ1 ͒ and a ϭ 0.5 ͑mm Ϫ1 ͒ and limited our photon tracking in a considered region of the tissue with Ϫ0.5 mm Յ x ͑or y͒ Յ 0.5 mm and 0 Յ z Յ 1.5 mm unless otherwise specified.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…The new propagation direction of the photon in the 3-D space after the scattering is determined by two angles, and , with respect to the incident direction of the photon before scattering. The scattering angle is the angle between the incident and the scattered directions governed by the Henyey-Greenstein distribution function 9 and is needed to satisfy ͗cos ͘ ϭ g. 10 The azimuthal angle is randomly chosen to determine the projection of the new direction in the plane perpendicular to the incident direction. Before the photon is allowed to propagate further after a scattering event, the total distance L traversed by the photon along its trajectory is calculated to test if it exceeds the predetermined L a .…”

Section: Methodsmentioning

confidence: 99%

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Monte Carlo simulation of converging laser beams propagating in biological materials

Song

Dong

et al. 1999

Appl. Opt.

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A new method of Monte Carlo simulation has been developed to simulate the spatial distribution of photon density of converging laser beams propagating in a turbid medium such as the phantom of biological tissue. This method can be used to obtain steady-state light distribution in the tissue phantom for a continuous-wave laser beam. We have calculated the steady-state distribution of the photon density and found important features that are uniquely related to the propagation of the converging beams in the tissue phantom.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Monte Carlo simulation of converging laser beams propagating in biological materials

Song

Dong

et al. 1999

Appl. Opt.

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“…The variations in energy deposition depth, light generation, and light transport processes determine how signal and noise are transferred through the phosphor screen. Many investigators have studied the effect of light transport on the overall image quality of photographic [1][2][3][4] and radiographic [5][6][7][8][9][10][11][12][13] imaging systems. Among them, it was Lubberts 13 who demonstrated that the normalized frequency-dependent correlated noise transfer function of an homogeneous screen is not proportional to the normalized modulation transfer (MTF) at the output of the screen.…”

Section: Introductionmentioning

confidence: 99%

Lubberts effect in columnar phosphors

et al. 2004

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Noise transfer in granular x-ray imaging phosphor screens is not proportional to the square of the magnitude of the signal transfer when the transfer properties are considered for the entire screen thickness, unless appropriately weighted at each depth of interaction. This property, known as the Lubberts effect, has not yet been studied in columnar structured screens because of a lack of a generalized description of the depth-dependent light transport. In this paper, we investigate the signal and noise transfer characteristics of columnar phosphors used in digital mammography detectors using DETECT-II, an optical Monte Carlo light transport simulation code. We first validate our choice of optical parameters for the description of granular and columnar screens using published normalized modulation transfer (MTF) experimental data. Our calculations of MTF match empirically measured MTFs for a granular film/screen analog system, and for an indirect x-ray digital imaging system with CsI:Tl screen representative of digital mammography systems. Using the depth-dependent spread functions and collection efficiencies, we calculate the signal and noise transfer functions and the Lubberts fraction, which is the ratio of the signal transfer function to the noise transfer function, for different screen thicknesses of granular and columnar phosphors. We find that the Lubberts fraction of a 85 microm granular screen model corresponding to a Gd2O2S:Tb screen is similar to the fraction for a 100 microm columnar CsI:Tl screen.

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“…The stochastic variations in energy deposition depth, light generation, and light transport processes determine how signal and noise are transferred through the detector. Many investigators have studied the effect of light transport on overall image quality of photographic (Berg, 1969; De Belder et al , 1965; DePalma and Gasper, 1972; Wolfe et al , 1968) and radiographic (Cavouras et al , 2000; Drangova and Rowlands, 1986; Gasper, 1973; Kandarakis and Cavouras, 2001; Lubberts, 1968; Van Metter and Rabbani, 1990; Nishikawa and Yaffe, 1990; Swank, 1973; Antonuk, 2002; Swindell et al , 1991; Wowk et al , 1994) imaging systems. Early work on scintillator screens relied on assumptions that allowed analytical solutions.…”

Section: A Review Of Light Transport Simulation Toolsmentioning

confidence: 99%

Modelling the transport of optical photons in scintillation detectors for diagnostic and radiotherapy imaging

2017

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Computational modelling of radiation transport can enhance the understanding of the relative importance of individual processes involved in imaging systems. Modelling is a powerful tool for improving detector designs in ways that are impractical or impossible to achieve through experimental measurements. Modelling of light transport in scintillation detectors used in radiology and radiotherapy imaging that rely on the detection of visible light plays an increasingly important role in detector design. Historically, researchers have invested heavily in modelling the transport of ionizing radiation while light transport is often ignored or coarsely modelled. Due to the complexity of existing light transport simulation tools and the breadth of custom codes developed by users, light transport studies are seldom fully exploited and have not reached their full potential. This topical review aims at providing an overview of the methods employed in freely available and other described optical Monte Carlo packages and analytical models and discussing their respective advantages and limitations. In particular, applications of optical transport modelling in nuclear medicine, diagnostic and radiotherapy imaging are described. A discussion on the evolution of these modelling tools into future developments and applications is presented.

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Light Diffusion in Photographic Layers: Its Influence on Sensitivity and Modulation Transfer*

Cited by 24 publications

References 1 publication

Monte Carlo simulation of converging laser beams propagating in biological materials

Monte Carlo simulation of converging laser beams propagating in biological materials

Lubberts effect in columnar phosphors

Modelling the transport of optical photons in scintillation detectors for diagnostic and radiotherapy imaging

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