Classification of compressed breast shapes for the design of equalization filters in x-ray mammography.
Classification of compressed breast shapes for the design of equalization filters in x-ray mammography.
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压缩乳房形状分类，用于 X 射线乳房 X 射线照相术中均衡滤波器的设计。
DOI：
10.1118/1.598272
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发表时间：
1998
期刊：
影响因子：
3.8
通讯作者：
Nick Petrick
中科院分区：
文献类型：
--
作者：
M. Goodsitt;H. Chan;Bob Liu;Shankar V. Guru;A. Ray Morton;Shyam Keshavmurthy;Nick Petrick
我们正在开发一种外部滤波器方法，用于均衡乳房X射线摄影中的X射线曝光。每个过滤器都经过专门设计，以匹配压缩的乳房边缘的形状，并优先衰减乳房周边区域的X射线束。实际上，这种方法应该只需要使用有限数量的定制过滤器。据推测，这将是可能的，如果压缩乳房可以分为有限数量的形状。进行研究以确定形状的数量。根据乳腺X线照片中受压乳房外边界的抛物线外观，用多项式方程y = ax 2 + bx 3和y = ax 2 + bx 3 + cx 4拟合边界。比较了这些方程的拟合优度。在K-Means聚类过程中采用a，B和a，B，c系数将470个CC视图和484个MLO视图边界分类为2-10个聚类。给定聚类内的边界的平均系数定义了“滤波器”形状，并且各个边界被平移和旋转以最佳地匹配该滤波器形状。计算单个边界和“滤波器”之间的平均均方根差以及这些差的标准差。用上述多项式方程重新拟合最佳移位和旋转的边界，并绘制用于聚类成功的视觉评估。两种多项式拟合都是适当的，2系数方程的均方根误差约为2 mm，3系数方程的均方根误差约为1 mm。虽然3-系数方程对原始边界的拟合是上级的，但对通过聚类确定的“过滤器”边界的匹配没有显著改善。开发和利用了各种改进的聚类方法，但没有一种聚类方法有重大改进。结果表明，3或4个滤波器形状可能适用于每个乳腺摄影投影（CC视图和MLO视图）。为了解释在被分类为具有特定形状的乳房的外围区域处观察到的暴露的广泛变化，可能有必要对薄、中等和厚乳房使用不同的滤波器。即使有了这个额外的要求，也应该可以根据需要使用少量的滤波器。
We are developing an external filter method for equalizing the x-ray exposure in mammography. Each filter is specially designed to match the shape of the compressed breast border and to preferentially attenuate the x-ray beam in the peripheral region of the breast. To be practical, this method should require the use of only a limited number of custom built filters. It is hypothesized that this would be possible if compressed breasts can be classified into a finite number of shapes. A study was performed to determine the number of shapes. Based on the parabolic appearance of the outer borders of compressed breasts in mammograms, the borders were fit with the polynomial equations y = ax2 + bx3 and y = ax2 + bx3 + cx4. The goodness-of-fit of these equations was compared. The a,b and a,b,c coefficients were employed in a K-Means clustering procedure to classify 470 CC-view and 484 MLO-view borders into 2-10 clusters. The mean coefficients of the borders within a given cluster defined the "filter" shape, and the individual borders were translated and rotated to best match that filter shape. The average rms differences between the individual borders and the "filter" were computed as were the standard deviations of those differences. The optimally shifted and rotated borders were refit with the above polynomial equations, and plotted for visual evaluation of clustering success. Both polynomial fits were adequate with rms errors of about 2 mm for the 2-coefficient equation, and about 1 mm for the 3-coefficient equation. Although the fits to the original borders were superior for the 3-coefficient equation, the matches to the "filter" borders determined by clustering were not significantly improved. A variety of modified clustering methods were developed and utilized, but none produced major improvements in clustering. Results indicate that 3 or 4 filter shapes may be adequate for each mammographic projection (CC- and MLO-view). To account for the wide variations in exposures observed at the peripheral regions of breasts classified to be of a particular shape, it may be necessary to employ different filters for thin, medium and thick breasts. Even with this added requirement, it should be possible to use a small number of filters as desired.
乳房X线扫描扫描均衡放射线照相。
影响因子：
3.8
作者：
Sabol,JM;Soutar,IC;Plewes,DB
通讯作者：
Plewes,DB
乳腺X线摄影中的曝光均衡技术。
影响因子：
6.7
作者：
Lam,KL;Chan,HP
通讯作者：
Chan,HP
X 射线束均衡对乳腺 X 线摄影成像的影响。
影响因子：
3.8
作者：
Lam,KL;Chan,HP
通讯作者：
Chan,HP