PET/CT with ¹⁸F–choline: Physiological whole bio-distribution in male and female subjects and diagnostic pitfalls on 1000 prostate cancer patients

Introduction: The ¹¹C/¹⁸F–choline is a PET/CT radiopharmaceutical useful in detecting tumors with high lipogenesis. ¹¹C/¹⁸F–choline uptake can occur in physiological conditions or tumors. The knowledge of its bio-distribution is essential to recognize physiologic variants or diagnostic pitfalls. Moreover, few information are available on the bio-distribution of this tracer in female patients. Our aim was to discuss some documented ¹⁸F–choline PET/CT pitfalls in prostate cancer patients. Our secondary aim was to describe the ¹⁸F–choline bio-distribution in the female body. Methods: We collected diagnostic pitfalls in three PET centers examining 1000 prostate cancer by ¹⁸F–choline PET/CT. All pitfalls were ensured by follow-up, imaging and/or histology. We also performed whole body ¹⁸F–choline PET/CT in 5 female patients. Results: 169/1000 (16.9%) patients showed pitfalls not owing to prostate cancer. These findings were due to inflammation, benign tumors while, in 1% of examined patients, a concomitant neoplasm was found. In the female body, the breast showed low physiological uptake. Conclusions: The accurate knowledge of ¹⁸F–choline PET/CT bio-distribution and diagnostic pitfalls is essential. Correlative imaging and histological exam are often necessary to depict pitfalls. In women, the uptake in the breast is due to the physiological gradient of ¹⁸F–choline uptake in the exocrine glands. Advances in knowledge: Our results confirm the possibility of ¹⁸F–choline uptake in several diseases other than prostate cancer. However, our experience was acquired on a large population and shows that a conspicuous amount of ¹⁸F–choline diagnostic pitfalls are easily recognizable and attributable to inflammation. A new advance in knowledge is the minimal difference in terms of physiological tracer bio-distribution between male and female patients. Implications for patient care: The knowledge of the physiological bio-distribution and of the potential pitfalls linked of a tracer could help physicians to choose the best diagnostic and therapeutic approaches for a better patient quality of life.