WAC 246-225-080
WAC 246-225-080. Radiographic systems other than fluoroscopic, dental intraoral, or veterinary systems—Source-to-skin or receptor distance
(1) Limitation. All radiographic systems shall be provided with a durable, securely fastened means to limit the source-to-skin distance to not less than 23 centimeters. The requirement can be met when the collimator or cone provides the required limits.
(2) Source to receptor distance measuring device. All radiographic systems shall be provided with a device or reference, other than a collimator light localizer, which will indicate the selected source to image receptor distance (SID) to within 2 percent of the indicated SID.