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The role of breast compression in scintimammography

A phantom model was used to study the effect of breast compression on signal-to-noise ratio (SNR) for a dedicated high-resolution gamma camera (Single Photon Emission Mammography, or 'SPEM') and a conventional camera as typically employed in prone scintimammography. The phantom was designed to simulate the effects of lesion size and of scatter from nearby torso activity. The phantom studies showed that lesions SNR was higher with the SPEM camera than with the conventional camera, and that SNR was always improved with compression for both cameras. Since the stage of breast cancer diagnosis affects patient prognosis, it is important to optimize breast examinations for small (i.e. Tla and Tlb) lesions. For one cm size lesions (clinical stage Tlc). SNR was maximized when compression was less than 12 cm, and little additional benefit was derived from further compression. For subcentimeter (clinical stage Tlb) lesions. SNR was maximized when compression was less than 6 cm. These data are consistent with a short clinical study in which detection sensitivity for small cancers was improved with the SPEM camera as compared to a conventional gamma camera. It is concluded that, in order to image early breast cancers (stage Tlb), it is important to apply breast compression.