Bone Scans

Introduction

A bone scan is a special imaging test used to look for areas of increased activity within bones. Unlike a regular X-ray, which mainly shows the shape and structure of bones, a bone scan helps doctors identify areas where the bone is actively repairing, inflamed, injured, or affected by disease. Bone scans are often ordered when a doctor suspects a stress fracture, infection, arthritis, loosening of a joint replacement, or spread of cancer to bone. They can also help identify the source of unexplained bone pain when regular X-rays appear normal.

How a Bone Scan Works

A bone scan works by using a small amount of radioactive material called a tracer. This tracer is injected into a vein and travels through the bloodstream to the bones. Areas of bone that are more active—because of healing, inflammation, or injury—absorb more of the tracer and appear as “hot spots” on the scan. A special camera then detects the radiation and creates images of the skeleton. There are several types of bone scans. A standard “nuclear medicine bone scan” is the most common. A three-phase bone scan looks at blood flow and bone activity in multiple stages and is often used to evaluate infections or complex pain conditions. Newer imaging techniques, such as SPECT scans (single-photon emission computed tomography), combine bone scan technology with CT imaging to provide more detailed information. Bone scans can help identify stress fractures, bone infections, arthritis, bone tumors, metastatic cancer, and areas of abnormal bone healing.

When a Doctor Might Order a Bone Scan

Doctors may order a bone scan when symptoms suggest a bone problem that cannot be clearly seen on standard X-rays. For example, stress fractures often do not appear on X-rays early on but may show up clearly on a bone scan. Bone scans are also commonly used to look for infections in bone (osteomyelitis), evaluate painful joint replacements, or identify whether cancer has spread to the skeleton. In orthopaedics, bone scans may help determine whether an area of pain is coming from increased bone activity around a joint, fracture, or tendon attachment site.

Concerns Related to Bone Scans

Although bone scans are very sensitive, they are not always very specific. This means they are good at showing that “something is abnormal,” but they often cannot determine exactly what the exact problem is. For example, a stress fracture, arthritis, infection, healing fracture, or bone tumor may all produce increased activity and look somewhat similar on a bone scan. Because of this, bone scan findings must be interpreted together with the patient’s symptoms, physical examination, X-rays, MRI scans, and other medical information. Bone scans also expose patients to a small amount of radiation, although the amount is generally considered low and safe for most people.

Summary

A bone scan is a test that helps doctors find areas where bones are irritated, injured, healing, or inflamed. A small amount of radioactive material is injected into the bloodstream, and areas of active bone show up brighter on the scan. Bone scans are useful for finding problems like stress fractures, infections, arthritis, or cancer in bone. However, they cannot always tell exactly what the problem is, so doctors often use them together with other tests such as X-rays or MRI scans.

Edited by Stephen Pinney MD, May 21st 2026.