Patient Radiation Exposure Information

Diagnostic Reference Level

(mR)

Achievable Level

(mR)

Diagnostic Reference Level

(mGy)

Achievable Dose

(mGy)

LARA Dose Limit

(mGy)

Fluoroscopy Rates

Background

Section health physicist inspectors routinely collect patient radiation exposure information during our regulatory inspections of x-ray facilities. The values measured are Exposure at Skin Entrance (ESE) measurements using technique factors used by the facility for an average-size patient. The exposure is measured free-in-air at the point where the x-rays enter the body. A chest phantom is used for photo-timed chests and the 16 cm CT phantom is used for CT adult head and pediatric body.

Diagnostic Reference Levels

Diagnostic Reference Levels (DRL) are based on data collected by the Radiation Safety Section during routine inspections of x-ray facilities. DRLs are set at the 75th percentile of the exposure distribution. Although DRLs are not regulations, they are considered by the Department to be upper limits which should not normally be exceeded for average-size patients.

Achievable Levels

Achievable levels are based on the median of the exposure distribution. The achievable level indicates a patient radiation exposure which should be readily attainable since 50% of Michigan facilities are already at this level.

Exposure Distribution Graphs

Graphs showing the distribution of radiation exposures over the preceding five years can be viewed by clicking on the desired x-ray projection listed below. These graphs are updated annually. They are used to review the Diagnostic Reference Levels and Achievable Levels.

National NEXT Program

The Nationwide Evaluation of X-Ray Trends (NEXT) is a national program conducted annually to measure the x-ray exposure that a standard patient receives for selected x-ray examinations. Click on this link for information on some of the NEXT surveys in the form of PDF trifolds.