数字乳腺系统中AOP的实现

The Realization of AOP in the Digital Mammary Gland System

这篇文章描述的是数字乳腺系统中实现自动优化参数(AOP)的一个方法。是应用一个图像链模型,对应合适的X射线参数和乳房类型计算对比噪声比(CNR)和平均腺体剂量(AGD)。优化的过程包括工作点的确定。这些工作点就是对应每个CNR水平和乳房类型提供最低可行的AGD的点。在设计的AOP模式中,推荐使用的剂量指标是人群中产生的剂量,即从分布在人群中各类乳房类型计算的平均AGD值。此方法目前已应用于新型数字乳腺成像设备的自动曝光控制中。用一个低剂量的预曝光估算乳房的厚度和组成,然后索引到一个包含一套工作点的表中。此方法产生的剂量范围与最先进的胶片乳腺成像相比减少两倍。使用此方法对所有乳腺类型的对比噪声比(CNR)和剂量都可控,考虑了单一和组合两者的风险。

This paper describes a method for automatic optimisation of parameters （AOP） in digital mammography systems. Using a model of the image chain, contrast to noise ratio （CNR） and average glandular dose （AGD） are computed for possible X-ray parameters and breast types. The optimisation process consists of the determination of the operating points providing the lowest possible AGD for each CNR level and breast type. The proposed metric for the dose used in the design of an AOP mode is the resulting dose to the population, computed by averaging the AGD values over the distribution of breast types in the population. This method has been applied to the automatic exposure control of new digital mammography equipment. Breast thickness and composition are estimated from a low dose pre-exposure and used to index tables containing sets of optimised operating points. The resulting average dose to the population ranges from a level comparable to state-of-the-art screen/iflm mammography to a reduction by a factor of two. Using this method, both CNR and dose are kept under control for al breast types, both individual and colective risk. taking into consideration.