Bone SPECT-CT

Bone SPECT-CT is a nuclear medicine scan that combines a picture of bone activity with a detailed CT picture of bone structure. A small amount of a radioactive tracer that seeks out active bone is used to show where the skeleton is working hard — repairing, remodelling or reacting to stress — and the fused CT then pinpoints exactly which bone or joint that activity belongs to. In the spine, it is especially useful for identifying an active source of pain among the many wear-and-tear changes that ordinary scans reveal.

Bone is living tissue that constantly renews itself, and this turnover speeds up wherever bone is strained, healing or inflamed. The tracer binds to the bone surface most strongly in these busy areas, so they show up brightly on the activity scan while quiet areas stay dim. On its own, that activity picture cannot always say precisely which structure is lit up. The CT, taken in the same sitting, provides the fine anatomical detail, and software fuses the two so each bright spot can be matched to the exact bone or joint beneath it — for example a specific facet joint, a pars stress injury, or a fracture.

You are given the tracer through a small injection into a vein, then wait a couple of hours while it settles into the skeleton; drinking fluids during this time helps clear what is not taken up and improves the images. When it is time to scan, you lie still while the camera slowly rotates around the area, and the CT portion is taken at the same visit. The scan is painless, though the waiting period means you should plan for a longer overall appointment. It involves a small amount of radiation, used when the diagnostic value justifies it.

Ordinary scans show what the spine looks like, but many of the changes they reveal are painless. Bone SPECT-CT adds the missing ingredient — activity — and ties it to precise anatomy, helping separate an active, likely painful area from harmless background wear. That can make a difficult diagnosis clearer and guide treatment, such as a targeted injection or procedure, to the right level. Findings are always interpreted alongside symptoms and other imaging.

• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —Royal College of Radiologists / British Nuclear Medicine Society — Guidance
• —British Association of Spine Surgeons (BASS)

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.