What is the relationship of DXA radiation to that of a chest x-ray?

• A. 10 times the radiation
• B. 1/5 radiation of a chest x-ray
• C. 1/10 radiation of a chest x-ray
• D. Equal radiation to a chest x-ray

Answer: (C)

The correct answer reflects a critical understanding of the radiation doses involved in various imaging techniques. Dual-energy X-ray absorptiometry (DXA) is used primarily to measure bone mineral density and assess osteoporosis. It utilizes lower doses of radiation compared to other common imaging modalities such as chest X-rays.

A chest X-ray typically exposes a patient to a radiation dose around 0.1 to 0.2 mSv (millisievert). In contrast, a DXA scan typically delivers an effective dose of approximately 0.001 to 0.01 mSv. This establishes that the radiation from a DXA scan is significantly lower, generally cited as about one-tenth (1/10) of that from a chest X-ray.

This comparison is essential for healthcare professionals to understand, as it highlights the safety profile of DXA imaging for patients, especially in populations that may require frequent monitoring of bone density, such as postmenopausal women or individuals on long-term corticosteroid therapy. The lower radiation exposure of DXA supports its use in regular screening programs without significant concern over cumulative radiation effects.