Peripheral quantitative computed tomography (pQCT) scan factsheet

Leg placed in pQCT scanner for testing

Introduction

Bones are made up of connective tissue, cells and minerals like calcium.  Bone density is the amount of mineral in the bone tissue. Bones that have more minerals are denser and stronger. Bones that have less minerals are less dense and can break more easily. 

Osteoporosis is a condition that causes bones to become less dense, weak, and brittle. Osteoporosis happens when bones lose minerals, such as calcium, more quickly than they replace them. 

It can also happen in children and adolescents if the amount of minerals in the bone does not increase at the normal rate.  

A peripheral quantitative computed tomography (pQCT) scan is used to help diagnose osteoporosis. It measures the size, shape, and density of the arm and leg bones. 

 Before the scan

Your child can eat and drink as usual before the scan.

Let your child’s treatment team know before the appointment if they have:

  • a plaster cast
  • another medical imaging study booked that uses contrast, like an MRI or CT scan.

These factors can affect the bone density measurements, so the scan may need to be rescheduled.

Your child must remove any thick or metallic objects from around their arms or legs, including jewellery and clothing with metal eyelets, clips or zippers.  

 During the scan

Generally, the steps of the scan are:

  1.  your child will sit on a chair
  2. they will place their arm or leg into the small, doughnut-shaped scanner
  3. the scanner will move slowly around the arm or leg, taking thousands of measurements.

 After the scan

You can leave once the results are checked by a nuclear medicine scientist or doctor.

The results will be sent to your child’s doctor within a couple of days. You will need to schedule a follow-up appointment with your child’s doctor to discuss the results.

 Management

Radiation

Your child will be exposed to a very small amount of radiation during the scan. The benefits of finding and treating bone problems are greater than the small risk of this low dose.

Supporting your child during the scan

Scans can be stressful for children. You can help by:

  • explaining why the scan is needed and how it works in simple words
  • bringing comfort items like a blanket, toy, or dummy
  • asking the treatment team about support from Child Life Therapy services.

Disclaimer

This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2025


This factsheet was produced with support from John Hunter Children's Hospital.