Experimental Investigation of the Necessity for Extra Flat Field Corrections in Quality Control of Digital Mammography

Pöyry, P; Zanca, Federica; Bosmans, Hilde

doi:10.1007/11783237_64

Cited by 4 publications

(3 citation statements)

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“…Based on this, pixel values could provide even more accurate results than estimation based on tube output measurements. However the drop in pixel values in the very first exposure after a longer time interval noted by Pöyry et al (2006) and also seen in our measurements was not related to a lower air kerma. This phenomenon was captured only once because in other cases some exposures were carried out before our measurements, and it should therefore be further investigated before drawing final conclusions.…”

Section: Discussionsupporting

confidence: 69%

“…To be able to use pixel values for air kerma estimation, the repeatability of the detector response needs to be evaluated. Variation in pixel values with the same manual exposure setting but in separate exposures has been observed (Pöyry et al 2006). However, Pöyry et al did not measure air kerma levels in their study and it was not clear whether the changes were based on the detector properties or real changes in the tube output level.…”

Section: Discussionmentioning

confidence: 97%

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Determining air kerma from pixel values in digital mammography

et al. 2009

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The pixels in digital detectors used in x-ray imaging can be considered as small dose meters. In mammography, the image detector area is commonly only partly covered by tissue and the incident air kerma could be monitored by using pixel values from the detector elements in the unattenuated primary beam area. The measured air kerma could be used for patient dose estimation. The air kerma and radiation quality dependence of the response of pixel values within a large exposure range for two direct digital detector types was experimentally investigated for this purpose. Using these calibration results, air kerma was measured from clinical images and compared with tube output calculation. The differences between the two methods were typically below 2% and measurements based on pixel values can therefore be recommended.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 97%

Determining air kerma from pixel values in digital mammography

et al. 2009

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“…On our system, a flat field correction is applied by the system itself and image inhomogeneity was not a problem. Attempting to make the measurements at the same location from subsequent images would have suffered from variations in tube output and detector response [22]. The variations between separate exposures are larger than the local variations within the central part of an image.…”

Section: Analysis Of Imagesmentioning

confidence: 97%

Experimental investigation on the choice of the tungsten/rhodium anode/filter combination for an amorphous selenium-based digital mammography system

et al. 2007

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The signal difference-to-noise ratio (SDNR) between aluminium sheets and a homogeneous background was measured for various radiation qualities and breast thicknesses to determine the optimal radiation quality when using a Novation DR mammography system. Breast simulating phantoms, with a thickness from 2 cm to 7 cm, and aluminium sheet, with a thickness of 0.2 mm, were used. Three different combinations of anode/filter material and a wide range of tube voltages were employed for each phantom thickness. Each radiation quality was studied using three different dose levels. The tungsten (W) anode and rhodium (Rh) filter combination achieved the specified SDNR at the lowest mean glandular dose for all the phantom thicknesses and X-ray tube voltages. The difference between the doses for different anode/filter combinations increased with the phantom thickness. For a 5-cm phantom, with a peak tube voltage of 27 kV and a SDNR of 5, the mean glandular dose associated with the use of W/Rh was reduced by 49% when compared to the molybdenum/molybdenum (Mo/Mo) anode/filter combination and by 33% when compared to Mo/Rh. Based on these measurements, the use of the W/Rh anode/filter can be recommended. It remains important, however, to select the appropriate dose level.

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Sample manuscript for an optical readout infrared imaging system based on polarization to eliminate stray light

Zhang

Cheng

Zhang

et al. 2013

Journal of Applied Physics

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In the optical readout uncooled infrared imaging technology, the stray light produced by the reflection of the optical component surfaces is acquired together with the effective signal light by the charge coupled device (CCD, the dynamic range of CCD is limited), which reduces the dynamic range of the effective signal light. In this paper, we present a polarized optical readout system to eliminate the stray light. Shading experiments show that, in the new system, the stray light is filtered out up to 86% and the dynamic range of the effective signal light significantly increase by 50%. Infrared Imaging experiments show that the noise equipment temperature difference value decreases by 35%, and the infrared imaging performance is greatly improved.

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Experimental Investigation of the Necessity for Extra Flat Field Corrections in Quality Control of Digital Mammography

Cited by 4 publications

References 1 publication

Determining air kerma from pixel values in digital mammography

Determining air kerma from pixel values in digital mammography

Experimental investigation on the choice of the tungsten/rhodium anode/filter combination for an amorphous selenium-based digital mammography system

Sample manuscript for an optical readout infrared imaging system based on polarization to eliminate stray light

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