Castronovo FP Jr. An attempt to standardize the radiodiagnostic risk statement in an Institutional Review Board consent form. Invest Radiol 1993;28:533–538. RATIONALE AND OBJECTIVES. The communication of a suitable radiation risk consent form statement to a potential research subject has always been difficult to formulate. Concomitant with this is the equally problematic task of ensuring that subjects understand the true risks of the study. In an effort to document how other Institutional Review Boards (IRBs) express radiation risk associated with participating in a research investigation, a questionnaire was developed and was sent to 23 large medical-research institutions. METHODS. Questions pertained to the manner of comparing risk, units for expressing radiation dose, patient population differentiation, and statements for given situations. In addition, each institution was asked to provide examples of radiation-related in-house consent form statements. Thereafter, the examples were forwarded to the responding institutions for grading. RESULTS. Fourteen responses were received and summarized. The majority compared the study test to a similar radioactivity study, Nuclear Regulatory Commission (NRC) occupational limits and/or Radioactive Drug Radiation Committee (RDRC) limits. There was an equal distribution of radiation units used; absorbed dose, dose equivalent, and effective dose equivalent. The majority of respondents did not differentiate between normal individuals and patient volunteers. Included in the 14 responses were 46 in-house generated radiation-related consent form statements. The latter were assembled and forwarded to the 14 responding institutions with instructions to “approve” or “disapprove” each. Nine statements obtained an 80% or greater acceptance rating, with three > 90%. The remaining were overwhelmingly rejected as suitable radiation risk statements. CONCLUSIONS. Based on the submitted material and statement grading results, recommendations were formulated toward producing a standard format for expressing radiation risk in the consent form. Effective dose equivalent in comparison to annual natural environmental radiation or occupational radiation dose limits were recommended based on these data. While an “optimum” radiation risk consent form statement may not be attainable, these results nevertheless provide recommendations based on a consensus of practitioners in the field.