DEXA DEXA Quality Assurance & Equipment Calibration

Question 1

How often should daily phantom QA scans be performed on a DEXA system?

Accepted Answer

Every day before patient scanning

Answer

Daily phantom scans must be performed every day prior to patient scanning to verify system accuracy and detect drift.

Question 2

What is the primary purpose of a spine phantom (e.g., Hologic or GE Lunar phantom) in DEXA QA?

Accepted Answer

To calibrate the system and detect BMD measurement drift

Answer

Spine phantoms are used to calibrate the DEXA system and monitor for measurement drift over time.

Question 3

A DEXA system's daily QC phantom result falls outside ±1.5% of the long-term average. What is the correct action?

Accepted Answer

Do not scan patients; investigate and contact the manufacturer

Answer

A phantom result outside the ±1.5% control limit requires halting patient scans and investigating the cause before proceeding.

Question 4

Which statistical tool is typically used to track DEXA daily phantom data over time and identify trends?

Accepted Answer

Shewhart control chart (QC chart)

Answer

Shewhart control charts plot daily phantom BMD values and visually flag drift or sudden shifts in machine performance.

Question 5

When should a DEXA system's cross-calibration be performed?

Accepted Answer

After major repairs, software upgrades, or detector replacement

Answer

Cross-calibration is required after any significant hardware or software change to ensure continuity of serial patient measurements.

(DEXA) DEXA Bone Density Scan Certification Practice Test