Radiological assessment of a new bone densitometer--the Lunar EXPERT

Area of Science:

• Medical Physics
• Radiological Protection
• Bone Densitometry

Background:

• Dual energy X-ray absorptiometry (DXA) is crucial for managing skeletal diseases like osteoporosis.
• Assessing patient and staff radiation doses from DXA is essential for safety, despite generally low levels.
• New DXA scanner technology necessitates updated dose evaluations.

Purpose of the Study:

• To estimate the effective dose (ED) to patients and staff from the new Lunar EXPERT DXA scanner.
• To compare radiation doses from the EXPERT system with those from the established Lunar DPX-L system.
• To evaluate the impact of scanning width on effective dose.

Main Methods:

• Entrance surface doses were measured for both DXA scanners.
• Effective doses (ED) for anteroposterior lumbar spine and proximal femur scans were calculated.
• Scattered dose rates (ambient dose equivalent) were measured at various distances from the scanners.

Main Results:

• The Lunar EXPERT showed significantly higher entrance surface doses (895 µGy) and maximum EDs (74.7 µSv for lumbar spine) compared to the DPX-L (10.25 µGy and 0.21 µSv, respectively).
• Using a smaller scanning width on the EXPERT system could reduce ED by over 50%.
• Scattered dose rates for the EXPERT (240 µSv/h at 50 cm) were considerably higher than for the DPX-L (<2 µSv/h at 50 cm), potentially requiring operator shielding.

Conclusions:

• While DXA doses remain low compared to other radiological procedures, the Lunar EXPERT exhibits higher patient and staff radiation exposure than the DPX-L.
• Implementing dose reduction techniques, such as optimizing scanning width, is recommended for the EXPERT system.
• Operator protection measures may be necessary for the EXPERT, depending on room size, unlike the DPX-L.