The Bone Density Clinic at UCSF Benioff Children’s Hospital Oakland has been measuring and interpreting pediatric bone densitometry scans since 2002. We are the only location in the Bay Area which specializes in bone health of children with chronic illness, as well as those with growth deficits, pubertal delay and developmental disabilities. The director, Ellen Fung, PhD, is an editor of the only textbook available in the clinical assessment of bone density for children.
What is Dual Energy X-Ray Absorptiometry (DXA)?
DXA is an instrument used to assess bone mineral content (BMC) and density (BMD) of the lumbar (lower) spine, hip, whole body, forearm and in some cases, distal femur. It is an FDA approved device that has been used for assessing bone health of post-menopausal women for the last 2 decades. More recently, this technology has been used to assess bone health of children, due to it’s rapid scan time, low radiation dose and robust reference data now available in pediatrics. During the procedure, X-rays pass through the patient and detectors register the varying levels of x-rays that are absorbed by the anatomical structures of the subject. The data obtained from this is calculated as BMC per area, or areal BMD. For most children their lumbar spine and whole body will be scanned, and for those >10 years of age, the hip will also be included in the examination.
Radiation Exposure
Reproduced from: Njeh CF, Fuers T, Hans D, Blake GM, Genant HK.
Radiation exposure in bone mineral density assessment.
Appl Radiat Isat 1999; 50(1):215-36.
The DXA was designed to release as little radiation as possible. The radiation exposure from DXA is minimal; less than a cross-country flight, or a 20th of a chest X-ray. As shown in the figure, the QDR-4500 Hologic machine, upon which our current bone densitometer is based, produces less radiation to the patient than 1 day of natural background radiation exposure.
Who should get a DXA scan?
Typically, children over the age of 5 who have a medical history significant for:
- Recurrent or low trauma fracture
- Chronic inflammatory disease
- Hypogonadism
- Immobilization
- Hematological disorders
- Long-term systemic glucocorticoid therapy
- Osteogenesis imperfecta
- And/or are in need of DXA for monitoring for treatment effect
If you have a question about your patient and whether or not a DXA scan is appropriate, please call our clinic at 510-428-3429.
Why should someone get a DXA scan?
The scans can identify whether a patient has low bone mass and help predict future fracture, indicated by a BMD Z-score of -2.0 or less. Results may then be used to help identify and resolve underlying etiology and modify treatment when applicable.
What information is provided from the DXA examination?
Your physician will be provided with a one page detailed summary report of the scan, with BMD Z-score interpretation as well as image quality copy of the scans that were obtained. The child’s bone mineral content (BMC) and bone mineral density (BMD) for each scan are the primary information revealed. BMD Z-scores, numbers indicating bone mass as compared to healthy reference individuals of the same age and gender group, are used to interpret the scans. Percent body fat can also be obtained from the whole body DXA scan.
How to order a scan?
An authorization for the procedure from a referring physician is required prior to making an appointment. We are able to take referrals from all local physicians and accommodate most insurance providers.
Contact the bone density clinic:
Telephone: 510-428-3429
Fax Number: 510-450-5877
Address: 5700 Martin Luther King Jr. Way, HEDCO Health Science Center, Oakland, CA 94609
CPT Code for Dual Energy X-ray Absorptiometry (DXA) Exam: 77080.
Providers, please complete this referral form and fax it to us at (510) 450-5877
QDR-4500 Hologic machine