Energy-Weighted Acquisition: Evaluation of Physical Characteristics and Clinical Utility

Abstract

Objective: Energy-weighted acquisition (EWA) is a commercially available technique designed to reduce the contribution of Compton scattered radiation in the final image. This study investigates the utility of EWA, using ^99mTc and ⁶⁷Ga, in both phantoms and clinical studies.

Methods: Phantom studies were performed to evaluate planar and SPECT image contrast, spatial resolution, count rate performance and attenuation correction. Clinical bone images and gallium images were acquired with and without EWA and were evaluated for anatomical and lesion definition.

Results: For ^99mTc, EWA was found to provide improved image contrast for both planar and SPECT images, with no deterioration in count rate performance and a small improvement in spatial resolution when compared to conventional on-peak and off-peak imaging. For ⁶⁷Ga, EWA was superior to conventional imaging using the lower two peaks, which in turn provided better contrast than using all three peaks.

Conclusion: The improvement in contrast in the phantom data was reflected in the clinical images. EWA images demonstrated greater anatomical definition in 60/65 ^99mTc bone scans and in 20/22 ⁶⁷Ga scans.