High kilovoltage digital exposure techniques and patient dosimetry.

Purpose: To explore digital exposure techniques during pelvic imaging on patient dosimetry, exposure indicator (EXI) values and image quality.

Methods: An experimental design was used to study the effect of varying kilovoltage peak (kVp) and milliampere-seconds (mAs) on a male phantom pelvis when using a direct digital radiography (DR) flat panel detector. The radiation intensity was varied by increasing the kVp and reducing mAs. Image quality was evaluated by assessing density, density differences, quantum noise and overall diagnostic quality.

Results: When the kVp was increased in 15% increments and mAs divided by half, the radiation dose to the gonads significantly decreased. The lowest and highest kVp exposure groups produced the lowest EXI values. There was no correlation between the thermoluminescent dosimeter milliroentgen (mR) measurements and the EXI values.

Conclusion: The results indicate that a pelvic DR image produced at 93 kVp and 12.5 mAs will reduce the gonadal dose while maintaining an image of diagnostic quality.