Quality assurance for grey-scale imaging.

In 1992, the American College of Radiology (ACR) recommended a specific phantom and image analysis procedure for (x-ray) mammography (American College of Radiology 1992). This event removed uncertainty in the USA regarding quality assurance (QA) in mammography. Although the phantom and analysis procedure are probably not ideal, existence of definitive recommendations has resulted in essentially 100% practice of regular QA in the clinic. The most urgent need for ultrasound (US) QA is that there exist specific recommendations from national and/or international organizations corresponding to the ACR mammography case. At the time of this writing, there continue to be a broad range of commercial phantom types available for use in US QA. Though suggested procedures for quality assurance have been published (AIUM 1995; American College of Radiology 1999), clinical facilities have not yet been given definitive guidance by authoritative organizations regarding a specific phantom or small set of phantoms that are adequate for routine QA testing. Thus, clinical personnel charged with QA are usually in a quandary regarding which phantoms to purchase and use, without confidence that those phantoms will not be rendered obsolete by future authoritative recommendations.