Assessment of energy-weighted acquisition in SPECT using ROC analysis.

Abstract

Energy-weighted acquisition is a technique for reducing Compton scatter effects in nuclear medicine images. The effect of energy-weighted acquisition on SPECT99mTc images was evaluated by comparing the energy-weighted acquisition images with those obtained using a 20% photopeak energy window. SPECT images were compared using receiver operator characteristic (ROC) experiments testing the observer's ability to perform a pseudoclinical task. The tasks were detecting cold lesions within a uniform background and cold lesions within images created with a tomographic brain phantom. ROC analysis for each phantom produced different results. No significant difference was found between the two acquisition techniques in detecting cold lesions on uniform backgrounds. Energy-weighted acquisition improved cold lesion detection significantly within the brain phantom in comparison with 20% photopeak acquisition. Lesion detection in 99mTcSPECT images can be improved using energy-weighted acquisition. This improvement, however, is dependent on the nature of the object being imaged. Images with structure show improved detection, whereas uniform images do not.