Digital pelvic radiography: increasing distance to reduce dose

Area of Science:

• Radiological Physics
• Medical Imaging Technology
• Radiation Protection

Background:

• Direct digital radiography (DR) is a widely used imaging modality.
• Optimizing radiation dose while maintaining diagnostic image quality is a primary concern in medical imaging.
• Source-to-image distance (SID) is a key parameter influencing both radiation dose and image quality.

Purpose of the Study:

• To evaluate the impact of varying source-to-image distance (SID) on image quality and radiation dose in anteroposterior (AP) pelvic direct digital radiography (DR) examinations.
• To determine if increasing SID beyond the standard can lead to dose reduction without negatively affecting image quality.

Main Methods:

• An anthropomorphic pelvic phantom underwent AP DR examinations with varying SIDs (80 cm to 147 cm) at a constant tube potential (80 kVp).
• Entrance surface dose (ESD) and effective dose (ED) were calculated for each SID.
• Image quality was assessed by blinded observers using a standardized rating system.
• The effect of grid usage on dose and image quality was also investigated.

Main Results:

• Increasing SID led to statistically significant reductions in both ESD and ED compared to the standard 100 cm SID.
• Decreasing SID below 100 cm resulted in significantly increased ESD and ED.
• Image quality showed a statistically nonsignificant minor increase with increasing SID.
• Grid removal decreased image quality but significantly lowered overall ESD and ED.

Conclusions:

• Utilizing a larger-than-normal SID for AP pelvic DR examinations can achieve significant reductions in patient radiation dose (ESD and ED).
• These dose reductions can be realized without a discernible loss in diagnostic image quality.
• Adjusting SID is an effective strategy for optimizing radiation protection in DR pelvic imaging.