A bone scan is an efficient diagnostic tool that can provide insights into the health of the bones. The scan can reveal the abnormalities or changes in the bones. A bone scan is sometimes called the radionuclide scan, bone scintigraphy, or nuclear medicine bone scan. Let’s have a look at how a bone scan can help people maintain their bone health. 
What is a bone scan?
A bone scan refers to the specialized radiology technique that can examine the bones to detect any abnormal changes. It is indicated for the diagnosis of chemical and physical changes in the bones. A bone scan can also be used to assess the progress of treatment in patients diagnosed with osteoporosis, osteopenia, bone cancer, or any other conditions affecting the bones. 
A bone scan uses nuclear radiology techniques in which a radioactive substance called a radionuclide is used to examine the bones. During the test, the radionuclide collects at the specific bone tissue where abnormal chemical or physical changes have occurred. 
The radionuclide also emits gamma radiation that can be detected by a scanner that processes the information in the forms of a picture of the bones.
The “hot spots” or the areas in the bones where the radionuclide is collected indicate the presence of abnormalities such as arthritis, bone tumors, bone infections, or trauma that are not usually seen on X-rays.
When do people need a bone scan?
Bone scans are advised for the early diagnosis of chronic conditions like osteopenia, osteoporosis, and bone cancers. 
Bone scans can also help to detect metastatic cancer that has spread to the bones from other organs of the body. Since cancer cells grow or multiply rapidly, they appear as hot spots on a bone scan. The stimulation of metabolism and repair in the affected bone tissues due to cancer are also reflected in the bone scan results in the forms of hot spots.
Bone scans are recommended for people who are undergoing treatment for cancer. Regular bone scans before and after cancer treatment can help to assess the recovery or the risk of relapse in the patient.  
Some other indications of a bone scan include:
- To assess the extent of bone trauma when ordinary X-rays do not reveal any abnormality
- To detect a fracture and bone infection that is difficult to locate
- To determine the age and extent of fractures
- To diagnose the cause of unexplained bone pain
- To assess the treatment response in patients with Paget’s disease and avascular necrosis
What does a bone scan involve?
A bone scan requires people to take some precautions before, during, and after the procedure as described beneath: 
Before a bone scan
- Generally, no fasting, sedation, or any other prior preparation is required for a bone scan.
- Remove all piercings and leave valuables and jewelry at home as you would need to remove them before the scan.
- Inform the doctor if you are pregnant, breastfeeding, or planning to get pregnant and discuss the safety of the procedure for the fetus or breastfed baby.
- Notify the radiologist if you are allergic to medications, iodine, or contrast dyes.
During a bone scan
- You will be asked to lie down on the scanner table and keep still while you pass through the scanner.
- The camera scans and takes pictures of the bones
- The scan usually takes about 30 to 60 minutes
After a bone scan
- Move slowly while getting up from the scanner table to avoid dizziness
- Drink plenty of water and empty your bladder frequently for 1 or 2 days after the scan to flush out radionuclide from your body
- If you notice pain, redness, or swelling at the site of injection, contact your doctor
- Do not undergo any other radionuclide procedures for 24 to 48 hours after the bone scan.
How does a bone scan help in the diagnosis of bone disorders?
A bone scan uses nuclear medicine technology that can pinpoint the areas of damage with high precision. A specialized instrument, known as the gamma camera, captures the state of the bone in the form of patterns of radiation. A computer translates these patterns into a two-dimensional image that can be used by your orthopedic physician for the accurate diagnosis of the condition.
A bone scan is a sensitive test, which means it can be used to detect even minor abnormalities related to bone metabolism.
Interpreting the results of a bone scan
The reports of the bone scan reflect the physical and chemical changes occurring in your bones. The correct interpretation of the results of a bone scan can help a person seek prompt medical advice to restore bone health.
The nuclear imaging report of a bone scan includes copies of the pictures and the description of the findings. The images of your bones may have darker “hot spots” in areas where the radionuclide molecules have accumulated. Depending on the size and location of these spots, your doctor would be able to diagnose the underlying abnormality and suggest appropriate treatment measures.
A bone scan may also reveal lighter or “cold spots” that could suggest a reduced blood supply to the affected tissues. The lighter spots may also occur due to certain forms of cancer.
The clinical expertise of the physician, supported by additional imaging and lab tests, would help in the definitive diagnosis of the condition.
When do people need a follow-up bone scan?
A follow-up bone scan is usually advised when an abnormality linked to a chronic disorder is found. Depending on the specific diagnosis, a bone biopsy and blood tests may be recommended to assess the extent of damage. In some cases, more sophisticated imaging tests like SPECT (single-photon emission computerized tomography) scans are needed to confirm the diagnosis.
A bone scan is considered a valuable diagnostic tool that can help people in the early detection of acute and chronic bone disorders such as fractures, osteoporosis, and bone cancer.
Bone scans are recommended for women above the age of 45 years to help them detect the abnormal age-related changes before serious complications occur. A bone scan can help to assess the bone density and detect trauma or cancerous changes allowing people to adopt appropriate measures to prevent the worsening of the condition.