EOS Imaging

EOS is a specialised low-dose imaging system that takes full-length pictures of the spine and lower limbs while you stand, capturing front-on and side-on views simultaneously. From these two synchronised images a three-dimensional model of the skeleton can be built. Its great advantages are a much lower radiation dose than conventional full-length X-rays and the ability to assess whole-body alignment and balance in a natural standing position.

Instead of a single burst of X-rays over a large plate, the EOS machine uses a narrow, slot-shaped beam that scans smoothly from head to feet, with a highly efficient detector that needs far less radiation to form an image. Two beams positioned at right angles capture the front and side views at the same moment, so the two pictures correspond exactly. Software then uses this matched pair to reconstruct a 3D model of the spine and legs, allowing precise measurement of curves, alignment and balance. The dose is substantially lower than standard radiography — studies report reductions of roughly a half to well over eighty per cent depending on the settings.

You stand still inside an open, cabin-like frame while the scanner passes slowly down your body over a number of seconds; the frame is open, so it rarely feels enclosing. You will be positioned in a standard posture and asked to keep still. The scan is painless. Its lower radiation dose is a particular benefit for children and young people with scoliosis who need repeated imaging over years of monitoring.

EOS is especially valuable for scoliosis and for assessing whole-body alignment and balance, where full-length standing images and accurate 3D measurements are needed. Delivering these with markedly less radiation makes it well suited to the repeated monitoring that growing patients require. It combines the load-bearing information of a standing X-ray with 3D reconstruction, at a fraction of the usual dose — a strong fit for deformity assessment and surgical planning.

• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —UK Health Security Agency — Ionising Radiation: Patient Dose Information
• —British Scoliosis Society

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.