Source image distance 4887689 168278470 2007-10-31T11:08:06Z SmackBot 433328 Date/fix the maintenance tags or gen fixes {{Unreferenced|date=October 2007}} '''Focus film distance (FFD)''' is the distance between the [[X-ray]] source and the film in diagnostic [[radiography]]. It has recently been superseded due to the replacement of film with computed radiography or direct digital radiography detectors. There are now various possible alternatives: '''source image distance''' (SID); focus image distance (FID); source receptor distance (SRD); and focus receptor distance (FRD). SID seems to be the most common - perhaps as it was already in use as a term in [[fluoroscopy]] to describe source intensifier distance. {{med-stub}}