Radiographic quality control devices.

Abstract

In this study, we evaluate eight radiographic quality control (QC) devices, which noninvasively measure the output from a variety of diagnostic x-ray production systems. When used as part of a quality assurance (QA) program, radiographic QC devices help ensure that x-ray equipment is working within acceptable limits. This in turn helps ensure that high-quality images are achieved with appropriate radiation doses and that resources are used efficiently (for example, by minimizing the number of repeat exposures required). Our testing focused on the physical performance, ease of use, and service and maintenance characteristics that affect the use of these devices for periodic, routine measurements of x-ray system parameters. We found that all the evaluated models satisfactorily measure all the parameters normally needed for a QA program. However, we did identify a number of differences among the models--particularly in the range of exposure levels that can be effectively measured and the ease of use. Three models perform well for a variety of applications and are very easy to use; we rate them Preferred. Three additional models have minor limitations but otherwise perform well; we rate them Acceptable. We recommend against purchasing two models because, although each performs acceptably for most applications, neither model can measure low levels of radiation. This Evaluation covers devices designed to measure the output of x-ray tubes noninvasively. These devices, called radiographic quality control (QC) devices, or QC meters, are typically used by medical physicists, x-ray engineers, biomedical engineers, and suitably trained radiographic technologists to make QC measurements. We focus on the use of these devices as part of an overall quality assurance (QA) program. We have not evaluated their use for other applications, such as acceptance testing. To be included in this study, a device must be able to measure the exposure- and kVp-related characteristics of most x-ray systems. At minimum, it must be able to make routine QC measurements of general radiographic, fluoroscopic, and most mammographic equipment. We prefer that it also be usable with dental x-ray systems, more advanced mammography systems (see the supplementary article on page 103), and computed tomography (CT) systems. The device may be a single unit, or it may be a kit consisting of multiple components that, when combined, can perform all the relevant measurements. The evaluated devices are designed to assess only x-ray production systems, not x-ray detection systems such as image intensifiers and film. Those types of systems are typically assessed using test phantoms and other tools that produce test images, which can be quantitatively measured and compared against standards.