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DEXA scan


What is a DEXA scan?

A DEXA scan is a way for doctors to see inside the body. It uses X-ray equipment to look at the bones. A DEXA scan is also called a “bone density test” or “bone densitometry.”  

Why does my child need a DEXA scan?

A DEXA scan helps measure how much calcium is in your child’s bones. Calcium is a mineral that helps bones stay strong. Without enough calcium, bones get thinner and weaker and are more likely to break. A DEXA scan can also show if treatment for thin, weak bones is working.

If your child has a condition that can weaken the bones, takes medicine that can weaken them, or is getting treatment for bone problems, she might need a DEXA scan every few months or every year during treatment.

How should I prepare my child for the scan?

If your child takes medicines with calcium or calcium supplements (such as daily vitamins), stop giving them at least 24 hours before the DEXA scan. If you have questions, please ask your child’s doctor or nurse.

Dressing your child for a DEXA scan

Your child might wear a hospital gown during the scan, or she might just wear his own clothes. Dress your child in loose, comfortable clothes with no metal snaps or zippers. This is important because metal shows up on DEXA scans. It can block your doctor’s view of your child’s bones. Other items to avoid are:

  • A watch, jewelry, or hair clips with metal, and
  • Glasses or dental retainers with metal in them.

Helping your child hold still

A DEXA scan takes 30 to 45 minutes. Your child needs to lie completely still, or the X-rays will be blurry. If your child is old enough to pretend, it might help if she pretends to sleep or be a statue.

If your child is younger than 5, she might need medicine to help her lie still during the scan. If she is a baby, the staff might ask you to feed her just before the scan. This can help a baby sleep through the scan.

If you think your child might have trouble staying still, talk to the St. Jude team.

Important things to tell us ahead of time

Please tell us before the scan if:

  • Your child recently had an exam or scan with barium or contrast dye. She might have to wait 10 to 14 days before having a DEXA scan.
  • Your child could be pregnant. If she is, a DEXA scan could hurt the baby.What happens during a DEXA scan?

Your child lies on a padded table while the DEXA scanner moves over her body. A DEXA scan usually takes pictures of the spine and hips, but sometimes scans the whole body.

If your child has a DEXA scan of the spine, a St. Jude team member will put your child’s legs up on a padded box to keep her back flat. If your child has a DEXA scan of the hip, a St. Jude team member will put your child’s foot in a brace. These adjustments help the scanner get the best pictures.

Your child might need to hold her breath for a few seconds during the scan. This keeps the pictures from being blurry. Your child might hear a humming noise from the scanner, but DEXA scans are not usually very noisy.

Does a DEXA scan hurt?

No. Taking X-rays does not hurt, and the St. Jude team will make your child as comfortable as possible.

Are DEXA scans safe for my child?

A DEXA scan is a low-dose X-ray. It uses much less radiation than a regular X-ray. If you are concerned about radiation, talk to your child’s doctor or nurse.

Will someone be with my child during the DEXA scan?

A St. Jude team member is with your child during the scan. The team member will go into the next room to turn on the X-ray machine but can hear and talk to your child. A parent can be in the room during the child’s scan as long as the parent wears a lead apron. (If pregnant, the parent will have to remain in the waiting room.) 

When will I get the results, and what do they mean?

It can take one (1) to several days to get DEXA scan results. Ask your child’s doctor when to expect them.

A DEXA scan gives 2 scores:

  • T score – This shows your child’s risk of breaking a bone.
  • Z score – This shows how much bone your child has compared to other children her age, size, and gender.


If you have questions about DEXA scans, you can ask your child’s doctor, nurse or radiation technologist.

This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

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