What is the role of positron-emission tomography (PET) scanning in the workup of solitary pulmonary nodules?

Updated: Aug 22, 2019
  • Author: Pujan H Patel, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

Whether positron-emission tomography (PET) scanning will be useful in a patient’s workup depends on (1) the clinical pretest probability of malignancy, (2) nodule morphology, (3) the size and position of the nodule, and (4) the scanning facility available. [28, 29]

Because malignant nodules have increased glucose metabolism compared with benign lesions and healthy lungs, enhancement of the lesion makes it likely to be malignant. Injection of analogue 18-F-2 fluorodeoxyglucose (FDG) is used to assess the metabolic activity. FDG-PET scans may be analyzed semiquantitatively using standardized uptake values (SUVs) to normalize measurements for the patient's weight and the injected dose of radioisotope.

Although visual analysis findings (depending on the experience and judgment of the nuclear medicine physician) may match SUV calculations, an SUV of less than 2.5 is considered indicative of a benign lesion.

FDG-PET scans are quite helpful in detecting mediastinal metastases, thus improving staging of noninvasive lung cancer.


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