BONE IMAGING WITH ENERGY-WEIGHTED ACQUISITION

Scattered radiation is the principal cause of image degradation in nuc lear imaging. Several strategies have been tried to reduce the contrib ution of scattered radiation in nuclear imaging including energy-weigh ted acquisition (EWA). EWA reduces the effect of scattered radiation b y assigning a positive value for primary photon and a negative value f or scattered radiation. The effect of EWA for lesion detection on bone scans was compared with a standard acquisition protocol, referred to as normal weighted acquisition (NWA), in 97 patients by simultaneously acquiring bone scan images using both protocols. EWA identified 436 l esions (mean 4.49) and NWA 415 lesions (mean 4.28). There was no stati stical difference in the number of lesions identified nor in the inten sity of uptake in these lesions when assessed qualitatively. Therefore , it is concluded that EWA does not enhance lesion detection on Tc-99m bone scans.