AAPM task group report 305: Guidance for standardization of vendor-neutral reject analysis in radiography.

Reject rate analysis is considered an integral part of a diagnostic radiography quality control (QC) program. A rejected image is a patient radiograph that was not presented to a radiologist for diagnosis and that contributes unnecessary radiation dose to the patient. Reject rates that are either too high or too low may suggest systemic department shortcomings in QC mechanisms. Due to the lack of standardization, reject data often cannot be easily compared between radiography systems from different vendors. The purpose of this report is to provide guidance to help standardize data elements that are required for comprehensive reject analysis and to propose data reporting and workflows to enable an effective and comprehensive reject rate monitoring program. Essential data elements, a proposed schema for classifying reject reasons, and workflow implementation options are recommended in this task group report.

Current state of practice regarding digital radiography exposure indicators and deviation indices: Report of AAPM Imaging Physics Committee Task Group 232.

Beginning with the advent of digital radiography systems in 1981, manufacturers of these systems provided indicators of detector exposure. These indicators were manufacturer-specific, and users in facilities with equipment from multiple manufacturers found it a challenge to monitor and manage variations in indicated exposure in routine clinical use. In 2008, a common definition of exposure index (EI) was realized in International Electrotechnical Commission (IEC) International Standard 62494-1 Ed. 1, which also introduced and defined the deviation index (DI), a number quantifying the difference between the detector EI for a given radiograph and the target exposure index (EIT ). An exposure index that differed by a constant from that established by the IEC and the concept of the deviation index also appear in American Association of Physicists in Medicine (AAPM) Report No. 116 published in 2009. The AAPM Report No. 116 went beyond the IEC standard in supplying a table (Table II in the report of TG-116) titled "Exposure Indicator DI Control Limits for Clinical Images," which listed suggested DI ranges and actions to be considered for each range. As the IEC EI was implemented and clinical DI data were gathered, concerns were voiced that the DI control limits published in the report of TG-116 were too strict and did not accurately reflect clinical practice. The charge of task group 232 (TG-232) and the objective of this final report was to investigate the current state of the practice for CR/DR Exposure and Deviation Indices based on AAPM TG 116 and IEC-62494, for the purpose of establishing achievable goals (reference levels) and action levels in digital radiography. Data corresponding to EI and DI were collected from a range of practice settings for a number of body parts and views (adults and pediatric radiographs) and analyzed in aggregate and separately. A subset of radiographs was also evaluated by radiologists based on criteria adapted from the European Guidelines on Quality Criteria for Diagnostic Radiographic Images from the European Commission. Analysis revealed that typical DI distribution was characterized by a standard deviation (SD) of 1.3-3.6 with mean DI values substantially different from 0.0, and less than 50% of DI values fell within the significant action limits proposed by AAPM TG-116 (-1.0 ≤ DI ≤ 1.0). Recommendations stemming from this analysis include targeting a mean DI value of 0.0 and action limits at ±1 and ±2 SD of the DI based on actual DI data of an individual site. EIT values, DI values, and associated action limits should be reviewed on an ongoing basis and optimization of DI values should be a process of continuous quality improvement with a goal of reducing practice variation.

New exposure indicators for digital radiography simplified for radiologists and technologists.

OBJECTIVE: The purpose of this article is to educate radiologists and technologists about the clinically relevant portion of the new digital radiography standards. CONCLUSION: Both the International Electrotechnical Commission (IEC standard 62494-1) and the American Association of Physicists in Medicine (AAPM Task Group 116) have developed similar standards for monitoring exposure in digital radiography to eliminate proprietary and confusing terminology. Radiologists and technologists will need to learn three new terms--exposure index, target exposure index, and deviation index--to understand the new standards.

Quality assurance: a comparison study of radiographic exposure for neonatal chest radiographs at 4 academic hospitals.

BACKGROUND: Little is known about exposure differences among hospitals. Large differences might identify outliers using excessive exposure. OBJECTIVE: We used the newly described exposure index and deviation index to compare the difference in existing radiographic exposures for neonatal portable chest radiographs among four academic children's hospitals. MATERIALS AND METHODS: For each hospital we determined the mean exposure index. We also set target exposure indices and then measured the deviation from this target. RESULTS: There was not a large difference in exposure index among sites. No site had an exposure index mean that was more than twice or less than half that of any other site. For all four sites combined, 92% of exposures had a deviation index within the range from -3 to +3. Thus exposures at each hospital were consistently within a reasonable narrow spectrum. CONCLUSION: Mean exposure index differences are caused by operational differences with mean values that varied by less than 50% among four hospitals. Ninety-two percent of all exposures were between half and double the target exposure. Although only one vendor's equipment was used, these data establish a practical reference range of exposures for neonatal portable radiographs that can be recommended to other hospitals for neonatal chest radiographs.

Quality assurance: using the exposure index and the deviation index to monitor radiation exposure for portable chest radiographs in neonates.

BACKGROUND: Many methods are used to track patient exposure during acquisition of plain film radiographs. A uniform international standard would aid this process. OBJECTIVE: To evaluate and describe a new, simple quality-assurance method for monitoring patient exposure. This method uses the "exposure index" and the "deviation index," recently developed by the International Electrotechnical Commission (IEC) and American Association of Physicists in Medicine (AAPM). The deviation index measures variation from an ideal target exposure index value. Our objective was to determine whether the exposure index and the deviation index can be used to monitor and control exposure drift over time. MATERIALS AND METHODS: Our Agfa workstation automatically keeps a record of the exposure index for every patient. The exposure index and deviation index were calculated on 1,884 consecutive neonatal chest images. Exposure of a neonatal chest phantom was performed as a control. RESULTS: Acquisition of the exposure index and calculation of the deviation index was easily achieved. The weekly mean exposure index of the phantom and the patients was stable and showed <10% change during the study, indicating no exposure drift during the study period. CONCLUSION: The exposure index is an excellent tool to monitor the consistency of patient exposures. It does not indicate the exposure value used, but is an index to track compliance with a pre-determined target exposure.