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20 April 2005 Scatter in digital mammography: antiscatter grid versus slot-scanning
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We are investigating the advantage of scatter removal by the slot-scanning method compared to antiscatter grids. We carry out model calculations for the signal-to-noise ratio simulating different geometrical settings for slot-scan systems. The results are compared with those for standard nonscanning mammography systems with and without anti-scatter grid. Monte Carlo simulations are performed in order to get a realistic amount of scatter radiation as input for the model estimates. We present the results as function of the compressed breast thickness equivalent to the scatter fraction. It is demonstrated that a perfect slot-scan system with 100% transmission of primary radiation and 100% suppression of scattered radiation improves SNR2, and correspondingly reduces dose, by a factor of less than 1.8, compared with conventional anti-scatter grids and otherwise the same detector DQE. For realistic geometry the advantage is considerably smaller. The advantage of scatter removal by employing a slot-scanning method is moderate because the scatter fraction is relatively low in mammography. For breast thickness up to 5 cm it turns out that it is advantageous to work without a grid due to the low scatter fraction, which questions a scatter reduction method in that region at all. The model can be used as a simple design tool.
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T. Mertelmeier and P. Bernhardt "Scatter in digital mammography: antiscatter grid versus slot-scanning", Proc. SPIE 5745, Medical Imaging 2005: Physics of Medical Imaging, (20 April 2005);

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