Effect of scatter and an antiscatter grid on the performance of a slot-scanning digital mammography system
- Imaging Research, Sunnybrook and Women's College Health Sciences Centre, 2075 Bayview Ave, Room SG12, Toronto, Ontario, M4N 3M5 (Canada)
The use of a grid increases perceptibility of low contrast objects in mammography. Slot-scan mammography provides a more dose efficient reduction of the scattered radiation reaching the detector than obtained with an antiscatter grid in screen-film or flat-panel digital mammography. In this paper, the potential of using a grid in a slot-scan system to provide a further reduction of scattered radiation is investigated. The components of the digital signal: primary radiation, off-focus radiation, scattered radiation, and optical fluorescence glare in a CsI(Tl) detector were quantified. Based on these measurements, the primary and scatter transmission factors (T{sub p},T{sub s}), scatter-to-primary ratio (SPR), signal-difference-to-noise ratio (SDNR), and the SDNR improvement factor (K{sub SDNR}) were obtained. Our results showed that the SPR ranged from 0.05 to 0.19 for breast thicknesses between 2 and 8 cm, respectively. The values of K{sub SDNR} ranged from 0.85 to 0.94. Because the slot-scanning system has an inherently low SPR, the increase in dose required when the grid is used outweighs the benefit of the small increase in SDNR. It is possible that greater benefit could be achieved by using a grid with a higher T{sub p}, such as obtained using air-core technology.
- OSTI ID:
- 20775111
- Journal Information:
- Medical Physics, Vol. 33, Issue 4; Other Information: DOI: 10.1118/1.2184445; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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