[Cancer detection with whole-body FDG PET images without attenuation correction]

Whole-body positron emission tomography (PET) using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) has been applied successfully for the detection of cancer. In PET studies, transmission scans for attenuation correction are usually performed. In whole-body PET studies, however, the transmission scans lengthen the acquisition time and are not practical for routine clinical use. Thirty-two patients underwent whole-body PET studies with transmission scans. A total of 106 lesions were true positive on corrected images. At the same time that the corrected images were being reconstructed, uncorrected images were also reconstructed and visually inspected. In a patient with a large breast cancer (11 cm in diameter), the parasternal metastatic lymph node was not identified on the uncorrected image because of image artifacts produced by high FDG accumulation in the breast cancer. In a patient with recurrent colonic cancer, paraaortic metastatic lymph nodes were not well visualized because of attenuation effects. However, 104 out of 106 (98.1%) lesions were recognizable on uncorrected images as well as corrected images. This suggests that uncorrected images can be used for the detection of cancers.