Flexible and Efficient Crossed-Grid System for General Radiography

描述（由申请人提供）：众所周知，常规的防散射网格在普通放射照相中控制散射的能力有限。近年来，由于使用效率较低（细、线密度高、铅含量低）的栅格，以及患者的体型不断增大，这个问题变得更加严重。因此，放射图像质量往往不足以回答有关创伤和其他临床领域的问题，患者需要接受额外的更高剂量，更昂贵的成像检查。在许多情况下，如果有更好的放射成像系统，这些额外的检查就可以消除，医疗保健费用也可以降低。我们提出了一个粗糙的，高比率的空气空间网格耦合到一个正交排列的低比率传统网格。总之，这些将有效地消除散射，并将具有与常用电网相当的初级传输。低比例网格与一系列源到图像距离（sid）兼容。粗糙的网格将有清晰的网格条，允许可变的sid和角度视图。为了建立一个紧凑和临床可接受的系统，粗网格只能移动一小段距离来模糊网格线。已经证明，这可以通过采用准梯形x射线管电流波形来实现。

DESCRIPTION (provided by applicant): It is known that conventional anti-scatter grids are limited in their ability to control scatter in general radiography. In recent years this problem has been aggravated by the use of less efficient (thin, high line density, low lead content) grids, and the increasing size of patients. As a result, radiographic image quality is often insufficient to answer questions concerning trauma and other clinical areas, and patients undergo additional higher dose, more expensive imaging exams. In many instances these additional exams could be eliminated and health care costs reduced if a better radiographic imaging system were available. We propose a coarse, high-ratio air interspace grid coupled to an orthogonally aligned low-ratio conventional grid. Together, these will effectively eliminate scatter and will have a primary transmission comparable to commonly used grids. A low-ratio grid is compatible with a range of source-to-image distances (SIDs). The coarse grid will have articulating grid slats, permitting variable SIDs and angled views. In order to build a compact and clinically acceptable system, the coarse grid can only move a short distance to blur out grid lines. It has been demonstrated that this can be accomplished by employing a quasi-trapezoidal x-ray tube current waveform. In Phase I we propose to demonstrate that an appropriate quasi-trapezoidal x-ray tube current waveform can be obtained in general radiography. In Phase II we propose to design and construct a compact and high efficiency crossed-grid system, interface it to an x-ray generator, and demonstrate that it can control scatter much more effectively than a conventional grid. The system will be able to accommodate general radiography, chest radiography, angled projections, tomography, and a range of SIDs. It can be used with either screen-film or digital image receptors, and will improve tomosynthesis and dual energy applications. RELEVANCE TO PUBLIC HEALTH: General radiography (x-ray images) plays an important role in health care delivery. Scattered radiation degrades image quality; social and technical trends have aggravated this problem in recent years. We propose a scatter control system that greatly increases the image quality of x- ray images without increasing patient dose.