Neuroendocrine tumors
Molecular imaging in neuroendocrine tumors: Molecular uptake mechanisms and clinical results
Critical Reviews in Oncology/Hematology 2009; 71:199-213

Neuroendocrine tumors can originate almost everywhere in the body and consist of a great variety of subtypes. The review focuses on molecular imaging methods using nuclear medicine techniques in neuroendocrine tumors, coupling molecular uptake mechanisms of radiotracers with clinical results.

Receptor-based imaging covers the molecular backgrounds of somatostatin, vaso-intestinal peptide (VIP), bombesin and cholecystokinin (CCK) receptors and their link with nuclear imaging. Metabolic imaging includes meta-iodo-benzylguanide (MIBG) and dimercapto-sulphuric acid (DMSA-V) scintigraphy as well as PET-based methods using radio-labeled analogues of amino acids, glucose, dihydroxyphenylalanine (DOPA), dopamine and tryptophan. Diagnostic sensitivities are presented for each imaging method and for each neuroendocrine tumor subtype.

Colorectal cancer
Performance of integrated FDG-PET/contrast-enhanced CT in the staging and restaging of colorectal cancer: Comparison with PET and enhanced CT
Eur J Radiol 2009, Article in press doi:10.1016/j.ejrad.2008.10.030

Diagnostic value of PET/CT as a one step examination was compared with PET or contrast-enhanced CT alone for staging or restaging of patients with colorectal cancer. In the study, 73 patients were included, out of which 26 underwent PET/CT for staging and 47 for restaging. Some 266 metastases could be detected in 60 patients. PET/CT had a superior lesion-based sensitivity (100%) when compared with contrast-enhanced CT (91%) and PET (85%) in staging and restaging patients with colorectal cancer.

Hepatocellular carcinoma
Imaging of proliferation in hepatocellular carcinoma with the in vivo marker 18F-Fluorothymidine
J Nucl Med 2009; 50:1441-1447

In the study, 18F-FLT PET was performed in 18 untreated patients with clinically suspected hepatocellular carcinoma. A total of 13 of 18 tumors (sensitivity, 72%; 95% confidence interval [CI], 47%-90%) showed focal 18F-FLT uptake higher than surrounding liver activity and were detectable as hot lesions. Five tumors were characterized as photopenic lesions and exhibited a comparable or lower 18F-FLT uptake than the surrounding liver tissue. When all lesions were considered, the mean 18F-FLT SUV was 7.8 and the maximum was 9.3. High initial 18F-FLT uptake was associated with reduced overall survival and could be an important prognostic factor in hepatocellular carcinoma.

Lung cancer
Detection of bone metastases in patients with lung cancer: 99mTc-MDP planar bone scintigraphy, 18F-fluoride PET or 18F-FDG PET/CT
Eur J Nucl Med Mol Imaging 2009; 36:1807-1812

The study compared the diagnostic accuracy of 18F-FDG PET/CT versus standard planar bone scintigraphy (BS) and 18F-NaF PET for the detection of bone metastases (BM) in non-small cell lung cancer (NSCLC). In 68 patients, 18F-FGD PET/CT and 18F-NaF PET were performed and in 58 patients 18F-FDG PET/CT and BS were done.

PET/CT showed more BM compared to 18F PET (53 vs. 40). However, 18F-NaF PET identified four patients with BM compared to negative findings on PET/CT. Integrated 18F-FDG PET/CT was found to be superior to BS in the detection of osteolytic BM in NSCLC and may obviate the need to perform additional BS or 18F-NaF PET in the staging of NSCLC, thereby reducing costs.

18F-FDG PET imaging in lung, breast and colon cancer
18F-FDG uptake in lung, breast, and colon cancers: molecular biology correlates and disease characterization
J Nucl Med 2009; Nov; 50:1820-1827

PET has been used for diagnosis, initial staging, restaging, prediction, and monitoring of treatment response, surveillance, and prognostication in a variety of cancers. Diagnostic information provided by 18F-FDG PET has led to improved clinical decision making and management changes in a substantial number of patients with cancer.

The review summarizes the current data on the correlation between the underlying molecular biology and the clinical observations of tumor 18F-FDG accumulation in three major human cancers: lung, breast and colon.