Phantom study of radiotracer concentration quantification in breast scintigraphy

The authors are developing a breast imaging system that combines digital X-ray mammography and gamma emission scintigraphy in an integrated unit. One potential value of such a combination is the ability to quickly obtain information about breast shape and lesion position within the breast via X-ray and then to use this information to perform corrections to the gamma image(s). In particular, the effects of gamma ray attenuation, gamma camera resolution, and scatter can be taken into account so as to better estimate the difference between the image contrast and true radioactivity contrast. The authors present results of a phantom study designed to test how well the lesion-to-background contrast can be predicted by this method. The preliminary results indicate that the effects of attenuation, partial volume averaging, and scatter on lesion image contrast can be modeled and suggest that the model might be usefully employed in the dual modality breast scanner to correct the breast scintigram for these effects.