TO THE EDITOR:

We read with great interest the article by Hara et al. (1), which was published in the September 2000 issue of The Journal of Nuclear Medicine. Although we agree with the authors that the FDG uptake in metastatic mediastinal lymph node lesions could be less than that of the primary cancer, this does not preclude our accurate detection of these metastatic lesions. The authors wanted to illustrate their points in the article but had forgotten the clinical skills of interpreting clinical PET. If one scales down the intensity in Figures 3 and 4, one can readily see the lesions in the mediastinum by FDG. The only case they presented that is not obvious to us is in Figure 2, which the authors presented with the wrong image of FDG. They used nonattenuated corrected images instead of the corresponding images with attenuation correction, which is known to show higher intensity than that of the former images. The foregoing reasons may explain the low-end sensitivity of detecting mediastinal lymph nodes observed by the authors as reported previously (2). We bring up these issues to stress the importance of clinical skills in conducting research studies on clinical applications of oncologic PET.