The aim of this guideline is to provide standards for the recommendation, performance, interpretation and reporting of Ga-PSMA PET/CT for prostate cancer imaging. These recommendations will help to improve accuracy, precision, and repeatability ofGa-PSMA PET/CT for prostate cancer essentially needed for implementation of this modality in science and routine clinical practice.

BACKGROUND. The aim was to assess the relevant distribution of the novel PET tracer 68Ga‐DOTATATE in neuroendocrine tumors (NETs) with combined positron emission tomography / computed tomography (PET/CT) and compare its performance with that of 18F‐FDG PET/CT. METHODS. The imaging findings with 68Ga‐DOTATATE and 18F‐FDG on 38 consecutive patients with a diagnosis of primary or recurrent NET were compared and correlated with tumor grade on histology based on ki67 and mitotic index. RESULTS. The sensitivity of 68Ga‐DOTATATE PET/CT was 82% (31 of 38) and that of 18F‐FDG PET/CT was 66% (25 of 38). The sensitivity of combined 68Ga‐DOTATATE and 18F‐FDG PET/CT was 92% (35 of 38). There was greater uptake of 68Ga‐DOTATATE than 18F‐FDG in low‐grade NET (median SUV 29 vs 2.9, P < .001). In high‐grade NET there was higher uptake of 18F‐FDG over 68Ga‐DOTATATE (median SUV 11.7 vs 4.4, P = .03). There was a significant correlation with predominant tumor uptake of 68Ga‐DOTATATE or 18F‐FDG and tumor grade on histology (P < .0001). CONCLUSIONS. 68Ga‐DOTATATE PET/CT is a useful novel imaging modality for NETs and is superior to 18F‐FDG for imaging well‐differentiated NET. Functional imaging with both 68Ga‐DOTATATE and 18F‐FDG has potential for a more comprehensive tumor assessment in intermediate‐ and high‐grade tumors. Cancer 2008. ©2008 American Cancer Society.

The aim of these guidelines is to assist nuclear medicine physicians in recommending, performing, reporting and interpreting the results of somatostatin (SST) receptor PET/CT imaging using 68Ga-DOTA-conjugated peptides, analogues of octreotide, that bind to SST receptors. This imaging modality should not be regarded as the only approach to visualizing tumours expressing SST receptors or as excluding other imaging modalities useful for obtaining comparable results. The corresponding guidelines of 111In-pentetreotide scintigraphy imaging have been considered and partially integrated with this text. The same has been done with the relevant and recent literature in this field and the final result has been discussed by distinguished experts.

111 In-diethylenetriaminepentaacetic acid (DTPA)-octreotide scintigraphy is currently the nuclear medicine imaging modality of choice for identifying neuroendocrine tumors. However, there are cohorts of patients in whom scintigraphy findings are negative or equivocal. We evaluated the role of 68 Ga-DOTATATE PET in a selected group of patients with negative or weakly positive findings on 111 In-DTPA-octreotide scintigraphy to determine whether 68 Ga-DOTATATE PET is able to detect additional disease and, if so, whether patient management is altered. Methods: Fifty-one patients with a histologically confirmed diagnosis of neuroendocrine tumors were included. Of the 51 patients, 35 who were negative and 16 equivocal for uptake on 111 In-DTPA-octreotide scintigraphy underwent 68 Ga-DOTATATE PET. Findings were compared using a region-by-region analysis. All findings were verified with CT or MRI. After 68 Ga-DOTATATE PET, all cases were reviewed to determine whether the 68 Ga-DOTATATE PET findings resulted in any alteration in management, in terms of suitability for peptide receptor therapy, somatostatin analogs, and surgery. Results: Of the 51 patients, 47 had evidence of disease on cross-sectional imaging or biochemically. 68 Ga-DOTATATE PET was positive in 41 of these 47 patients (87.2%). No falsepositive lesions were identified. 68 Ga-DOTATATE PET detected 168 of the 226 lesions (74.3%) that were identified with crosssectional imaging. 68 Ga-DOTATATE PET identified significantly more lesions than 111 In-DTPA-octreotide scintigraphy (P , 0.001). There was no correlation between 68 Ga-DOTATATE uptake and histologic grade of neuroendocrine tumors. 68 Ga-DOTATATE imaging changed management in 36 patients (70.6%), who were subsequently deemed suitable for peptide receptor-targeted therapy. Conclusion: In patients with negative or equivocal 111 In-DTPA-octreotide findings, 68 Ga-DOTATATE PET identifies additional lesions and may alter management in most cases.

Early diagnosis of tuberculosis (TB) is necessary for effective treatment. In primary pulmonary TB, chest radiography remains the mainstay for the diagnosis of parenchymal disease, while computed tomography (CT) is more sensitive in detecting lymphadenopathy. In post-primary pulmonary TB, CT is the method of choice to reveal early bronchogenic spread. Concerning characterization of the infection as active or not, CT is more sensitive than radiography, and (18)F-fluorodeoxyglucose positron emission tomography/CT ((18)F-FDG PET/CT) has yielded promising results that need further confirmation. The diagnosis of extrapulmonary TB sometimes remains difficult. Magnetic resonance imaging (MRI) is the preferred modality in the diagnosis and assessment of tuberculous spondylitis, while (18)F-FDG PET shows superior image resolution compared with single-photon-emitting tracers. MRI is considered superior to CT for the detection and assessment of central nervous system TB. Concerning abdominal TB, lymph nodes are best evaluated on CT, and there is no evidence that MRI offers added advantages in diagnosing hepatobiliary disease. As metabolic changes precede morphological ones, the application of (18)F-FDG PET/CT will likely play a major role in the assessment of the response to anti-TB treatment.