Coherent scatter in diagnostic radiology
作者:
P. C. Johns,
M. J. Yaffe,
期刊:
Medical Physics
(WILEY Available online 1998)
卷期:
Volume 10,
issue 1
页码: 40-50
ISSN:0094-2405
年代: 1998
DOI:10.1118/1.595443
出版商: American Association of Physicists in Medicine
数据来源: WILEY
摘要:
Coherent scatter is often ignored in diagnostic radiology because its cross section is relatively small, and because it is assumed to be indistinguishable from primary radiation. Single‐scatter calculations, however, show that coherently scattered photons diverge sufficiently from the primary ray to degrade image contrast, and that they account for a significant fraction of the total scattered energy fluence at the image receptor. Grids and large air gaps are less effective in reducing coherent single scatter than incoherent and multiple scatter. For radiography of the abdomen, coherent first scatter comprises 10% of total scatter and 26% of the primary fluence before a grid, and on the order of 22% and 7.5%, respectively, behind a grid. Coherent first scatter comprises a higher fraction of the total amount of scatter for lower energy examinations such as mammography.
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