The clinical use of PET with (11)C-acetate

Abstract

The aim of this review is to evaluate clinical applications of (11)C-acetate positron emission tomography (PET). Acetate is quickly metabolized into acetyl-CoA in human cells. In this form it can either enter into the tricarboxylic acid cycle, thus producing energy, as happens in the myocardium, or participate in cell membrane lipid synthesis, as happens in tumor cells. (11)C-acetate PET was originally employed in cardiology, to study myocardial oxygen metabolism. More recently it has also been used to evaluate myocardial perfusion, as well as in oncology. The first studies of (11)C-acetate focused on its use in prostate cancer. Subsequently, (11)C-acetate was studied in other urological malignancies, as well as renal cell carcinoma and bladder cancer. Well differentiated hepatocellular carcinoma represents an (18)F-fluoro-deoxyglucose ((18)F-FDG) PET pitfall, so many authors have proposed to use (11)C-acetate in addition to (18)F-FDG in studying this tumor. (11)C-acetate PET has also been used in other malignancies, such as brain tumors and lung carcinoma. Some authors reported a few cases in which (11)C-acetate PET incidentally found multiple myeloma or rare tumors, such as thymoma, multicentric angiomyolipoma of the kidney and cerebellopontine angle schwannoma. Lastly, (11)C-acetate PET was also employed in a differential diagnosis case between glioma and encephalitis. The numerous studies on (11)C-acetate have demonstrated that it can be used in cardiology and oncology with no contraindications apart from pregnancy and the necessity of a rapid scan. Despite its limited availability, this tracer can surely be considered to be a promising one, because of its versatility and capacity to even detect non (18)F-FDG-avid neoplasm, such as differentiated lung cancer or hepatocellular carcinoma.

Keywords: 11C-acetate; Positron emission tomography (PET); brain tumor; cancer; cardiology; liver cancer; prostate cancer.

Figure 1

¹¹C-acetate PET scan (fused image) of a patient with prostate cancer. The figure shows increased ¹¹C-acetate uptake in the prostate of this patient.

Figure 2

¹¹C-acetate PET scan (fused image) of a patient with HCC who had undergone partial liver resection. We can notice abnormal uptake in right hypochondrium of this patient, just below the liver.

Figure 3

¹¹C-acetate PET scan (fused image) of a patient with metastatic HCC. We can notice left lung metastasis (sub-pleurical region) derived from HCC.

Figure 4

¹¹C-acetate PET scan (fused image) of a patient with proved FNH. We can notice abnormal uptake of acetate in the liver (VII segment); this finding could not be distinguished from a focal HCC.

Figure 5

¹¹C-acetate PET scan (fused image) of a patient with metastatic RCC. The figure shows bone metastasis and in particular we can notice abnormal uptake of the tracer in the left ischium.