Beam quality independent attenuation phantom for estimating patient exposure from x-ray automatic exposure controlled chest examinations

Abstract

The periodic assessment of exposures in diagnostic radiology is an important part of a comprehensive quality assurance program. The most frequent radiologic examination conducted in the United States is chest radiography. Automatic exposure controlled (AEC) techniques are often used for this exam, and a standard patient-equivalent chest phantom is useful when estimating patient exposures on such systems. This is of particular importance if exposures are to be compared among AEC systems with different entrance x-ray spectra. Such a phantom has been developed to facilitate surveys of the average patient exposure from AEC posteroanterior chest radiography. The phantom is relatively lightweight and easily transportable, sturdy and made of readily available and relatively inexpensive materials (Lucite and aluminum). It accurately simulates the primary and scatter transmission through the lung-field regions of a patient-equivalent anthropomorphic phantom for x-ray spectra typically used in chest radiography. A clinical evaluation has been conducted to verify the patient equivalence of the phantom. Measurements of patient entrance skin exposure were obtained for a large number of patients on a variety of x-ray systems operated in the AEC mode using one or both lung-field detectors. Comparison of these data with exposure estimates derived from the phantom indicate that the phantom attenuates the x-ray beam in such a way that it can be employed to accurately and consistently estimate the mean exposure of the average patient under a variety of radiographic conditions. The design, development, and evaluation of the patient-equivalent attenuation phantom is described.

Contrast-detail evaluation and dose assessment of eight digital chest radiography systems in clinical practice

“…The CDRAD object was placed in a LucAl phantom [6]. This phantom simulates lung transmission characteristics and is constructed from slabs of polymethylmethacrylate (PMMA) and aluminum.…”

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system

“…The overall thickness of the phantom is 267.1 mm, with a total of 4.1 mm Al, 73 mm PMMA and a 190-mm air gap sandwiched between the front and back sheets of PMMA. The positions and geometry of the relevant compartments have been shown to provide accurate simulation of the primary and scatter transmission through the lung field of an average patient equivalent to an anthropomorphic chest phantom (Radiology Support Devices, Long Beach, CA) in the diagnostic energy range imaged in a PA orientation [35]; the phantom has subsequently been endorsed in the USA by the Food and Drug Administration [36]. We used the original version of the phantom in this study [23] but have also used a slightly modified version of it in previous work with some success [37][38][39].…”

Evaluation of a commercial cardiac motion phantom for dual‐energy chest radiography

“…For comparison, the duration of AEC exposures during annual testing using the LucAl chest phantom (Center for Devices and Radiological Health, Silver Spring, MD) (7) is shown for each machine. The LucAl chest phantom is designed to rpresent an adult of average dimensions (22.5 cm thick thorax).…”