Diagnostic Reference Levels in Medical Imaging:
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Diagnostic Reference Levels in Medical Imaging: Recommendations for Applications in the United States National Council on Radiation Protection and Measurement Presently in draft, under revision after review by Program Area Committee.
Diagnostic Reference Levels in Medical Imaging:
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Diagnostic Reference Levels in Medical Imaging: • Recommendations for Applications in the United States • National Council on Radiation Protection and Measurement • Presently in draft, under revision after review by Program Area Committee. • NCRP Council Review, available to public for comment ~January 2010
NCRP SC 4-3 Committee Consultants
What are Diagnostic Reference Levels? • DRLs are investigational levels • Based on survey data of state-of-the-practice facilities • Typically set at 75th percentile of survey data • Set at national level by imaging professionals • Updated on regular (five-year?) basis • If facility exceeds DRL, optimization is necessary
What Is Optimization? • The goal of optimization— • Image quality appropriate for the medical imaging task • and • Radiation dose adequate to provide the appropriate image quality
What areAchievable Doses? • DRLs impact 25% of facilities, i.e., those above the 75th percentile. • Achievable Doses are levels at which state-of-the-art facilities practice • Achievable Doses are set at the 50th percentile of the survey distributions • Rationale– if 50% of facilities can achieve these levels (or better), then all facilities should be able function at this level
What are Reference Levels? • RLs are similar to DRLs • Apply to Interventional Radiology, Nuclear Medicine • Based on measured patient doses in clinical setting
European Experience • HPA (formerly NRPB) started promoting DRLs and Achievable Doses in 1980s • UK has seen a 50% decrease in median doses from x-ray examinations over 20 years • DRLs required by EU for all member states • Most countries have seen decreases in patient doses as a result
NCRP Data Sources • NEXT • ACR • RAD-IR Study (Miller, et al.) • SNM, NCRP 2010 Survey, 2008 Survey of Pediatric Hospitals (Treves, et al.)
NEXT— Major Source of Data • Nationwide Evaluation of X-Ray Trends (NEXT) survey data (phantom data) • About 350 facilities surveyed in US • One projection per year • Funded by FDA, ACR, and others • Carried out by CRCPD with state agency participation
NCRP Report on DRLs For Adult and Pediatric Projections • Radiographic and Fluoroscopic* • Computed Tomography* • Dental Radiography* • Interventional Radiology (RLs) • Nuclear Medicine (RLs) • *6 Adult, 2 Peds, 3 Adult CT, 2 Peds CT, 4 Dental
Future Needs? • Database (Dose Registry) of patient doses per projection, in order to update DRLs, Achievable Doses, and RLs • Present sources scattered, different information– some phantom, some patient • Optimization requires up to date information on image quality and patient dose
Summary • NCRP’s DRLs, RLs, and Achievable Doses are the key to Optimization • Optimization is the key to quality medical imaging and appropriate radiation doses
Questions or Comments?? • Joel E. Gray, Ph.D • Phone +1 708-703-0260 • e-mail JoelGray@DIQUAD.com