Search for new phenomena in the W W to ell u ell' u' final state in pp collisions at sqrts=7 TeV with the ATLAS detector

This Letter reports a search for a heavy particle that decays to WW using events produced in pp collisions at root s = 7 TeV. The data were recorded in 2011 by the ATLAS detector and correspond to an integrated luminosity of 4.7 fb(-1). WW -> lvl'v' (l,l' = e or mu) final states are considered and the distribution of the transverse mass of the W W candidates is found to be consistent with Standard Model expectations. Upper limits on the production cross section times branching ratio into W boson pairs are set for Randall-Sundrum and bulk Randall-Sundrum gravitons, which result in observed 95% CL lower limits on the masses of the two particles of 1.23 TeV and 0.84 TeV, respectively.

Glucagon-like peptide-1 versus somatostatin receptor targeting reveals 2 distinct forms of malignant insulinomas

Glucagon-like peptide-1 (GLP-1) receptor imaging is superior to somatostatin receptor subtype 2 (sst(2)) imaging in localizing benign insulinomas. Here, the role of GLP-1 and sst(2) receptor imaging in the management of malignant insulinoma patients was investigated.

Does intravenous Δ9-tetrahydrocannabinol increase dopamine release? A SPET study

Intravenous (IV) Δ9-tetrahydrocannabinol (THC) induces transient psychotic symptoms in healthy subjects and in schizophrenic patients, but the psychotomimetic mechanism is unknown. One possibility is that THC stimulates dopamine (DA) release in the striatum. In this study we tested whether IV THC led to an increase in striatal DA release compared to placebo. We also investigated whether DA release and positive psychotic symptoms were related. Eleven healthy male volunteers completed two 123I-iodobenzamide ([123I]IBZM) single photon emission tomography (SPET) sessions and received IV THC (2.5 mg) or placebo in a randomized counterbalanced order, under double-blind conditions. Analysable data were obtained from nine participants. The Positive and Negative Syndrome Scale (PANSS) was used to rate psychotomimetic effects. Striatal binding index values were calculated using the occipital cortex as a reference region. Both the PANSS positive and general symptoms increased significantly at 30 min following IV THC. There were no significant differences in binding index in the caudate or putamen under THC compared to placebo conditions. Positive psychotic symptoms and DA release were unrelated. THC did not lead to a significant increase in DA release even though the dose was sufficient for participants to have psychotic symptoms. These findings do not support a central role for striatal DA in THC-elicited psychosis.

Novel positron emission tomography/computed tomography of diffuse parenchymal lung disease combining a labeled somatostatin receptor analogue and 2-deoxy-2[¹⁸F]fluoro-D-glucose

We prospectively investigated the potential of positron emission tomography (PET) using the somatostatin receptor (SSTR) analogue ⁶⁸Ga-DOTATATE and 2-deoxy-2[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) in diffuse parenchymal lung disease (DPLD). Twenty-six patients (mean age 68.9 ± 11.0 years) with DPLD were recruited for ⁶⁸Ga-DOTATATE and ¹⁸F-FDG combined PET/high-resolution computed tomography (HRCT) studies. Ten patients had idiopathic pulmonary fibrosis (IPF), 12 patients had nonspecific interstitial pneumonia (NSIP), and 4 patients had other forms of DPLD. Using PET, the pulmonary tracer uptake (maximum standardized uptake value [SUV(max)]) was calculated. The distribution of PET tracer was compared to the distribution of lung parenchymal changes on HRCT. All patients demonstrated increased pulmonary PET signal with ⁶⁸Ga-DOTATATE and ¹⁸F-FDG. The distribution of parenchymal uptake was similar, with both tracers corresponding to the distribution of HRCT changes. The mean SUV(max) was 2.2 ± 0.7 for ⁶⁸Ga-DOTATATE and 2.8 ± 1.0 (t-test, p  =  .018) for ¹⁸F-FDG. The mean ⁶⁸Ga-DOTATATE SUV(max) in IPF patients was 2.5 ± 0.9, whereas it was 2.0 ± 0.7 (p  =  .235) in NSIP patients. The correlation between ⁶⁸Ga-DOTATATE SUV(max) and gas transfer (transfer factor of the lung for carbon monoxide [TLCO]) was r  =  -.34 (p  =  .127) and r  =  -.49 (p  =  .028) between ¹⁸F-FDG SUV(max) and TLCO. We provide noninvasive in vivo evidence in humans showing that SSTRs may be detected in the lungs of patients with DPLD in a similar distribution to sites of increased uptake of ¹⁸F-FDG on PET.

K(L) --> pi0 e+ e- and K(L) --> pi0 mu+ mu-: A binary star on the stage of flavor physics

A systematic analysis of New Physics impacts on the rare decays KL→π0ell+ell- is performed. Thanks to their different sensitivities to flavor-changing local effective interactions, these two modes could provide valuable information on the nature of the possible New Physics at play. In particular, a combined measurement of both modes could disentangle scalar/pseudoscalar from vector or axial-vector contributions. For the latter, model-independent bounds are derived. Finally, the KL→π0μ+μ- forward-backward CP-asymmetry is considered, and shown to give interesting complementary information.

Comparison of 68Ga-DOTANOC and 68Ga-DOTATATE PET/CT within patients with gastroenteropancreatic neuroendocrine tumors

Somatostatin receptor PET tracers such as [68Ga-DOTA,1-Nal3]-octreotide (68Ga-DOTANOC) and [68Ga-DOTA,Tyr3]-octreotate (68Ga-DOTATATE) have shown promising results in patients with neuroendocrine tumors, with a higher lesion detection rate than is achieved with 18F-fluorodihydroxyphenyl-l-alanine PET, somatostatin receptor SPECT, CT, or MR imaging. 68Ga-DOTANOC has high affinity for somatostatin receptor subtypes 2, 3, and 5 (sst2,3,5). It has a wider receptor binding profile than 68Ga-DOTATATE, which is sst2-selective. The wider receptor binding profile might be advantageous for imaging because neuroendocrine tumors express different subtypes of somatostatin receptors. The goal of this study was to prospectively compare 68Ga-DOTANOC and 68Ga-DOTATATE PET/CT in the same patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and to evaluate the clinical impact of 68Ga-DOTANOC PET/CT. Methods: Eighteen patients with biopsy-proven GEP-NETs were evaluated with 68Ga-DOTANOC and 68Ga-DOTATATE using a randomized crossover design. Labeling of DOTANOC and DOTATATE with 68Ga was standardized using a fully automated synthesis device. PET/CT findings were compared with 3-phase CT scans and in some patients with MR imaging, 18F-FDG PET/CT, and histology. Uptake in organs and tumor lesions was quantified and compared by calculation of maximum standardized uptake values (SUVmax) using volume computer-assisted reading. Results: Histology revealed low-grade GEP-NETs (G1) in 4 patients, intermediate grade (G2) in 7, and high grade (G3) in 7. 68Ga-DOTANOC and 68Ga-DOTATATE were false-negative in only 1 of 18 patients. In total, 248 lesions were confirmed by cross-sectional and PET imaging. The lesion-based sensitivity of 68Ga-DOTANOC PET was 93.5%, compared with 85.5% for 68Ga-DOTATATE PET (P = 0.005). The better performance of 68Ga-DOTANOC PET is attributed mainly to the significantly higher detection rate of liver metastases rather than tumor differentiation grade. Multivariate analysis revealed significantly higher SUVmax in G1 tumors than in G3 tumors (P = 0.009). This finding was less pronounced with 68Ga-DOTANOC (P > 0.001). Altogether, 68Ga-DOTANOC changed treatment in 3 of 18 patients (17%). Conclusion: The sst2,3,5-specific radiotracer 68Ga-DOTANOC detected significantly more lesions than the sst2-specific radiotracer 68Ga-DOTATATE in our patients with GEP-NETs. The clinical relevance of this finding has to be proven in larger studies.

Glucagon-like peptide-1 receptor imaging for the localisation of insulinomas: a prospective multicentre imaging study

BACKGROUND Small benign insulinomas are hard to localise, leading to difficulties in planning of surgical interventions. We aimed to prospectively assess the insulinoma detection rate of single-photon emission CT in combination with CT (SPECT/CT) with a glucagon-like peptide-1 receptor avid radiotracer, and compare detection rates with conventional CT/MRI techniques. METHODS In our prospective imaging study, we enrolled adults aged 25-81 years at centres in Germany, Switzerland, and the UK. Eligible patients had proven clinical and biochemical endogenous hyperinsulinaemic hypoglycaemia and no evidence for metastatic disease on conventional imaging. CT/MRI imaging was done at referring centres according to standard protocols. At three tertiary nuclear medicine centres, we used whole body planar images and SPECT/CT of the abdomen up to 168 h after injection of (111)In-[Lys40(Ahx-DTPA-(111)In)NH2]-exendin-4 ((111)In-DTPA-exendin-4) to identify insulinomas. Consenting patients underwent surgery and imaging findings were confirmed histologically. FINDINGS Between Oct 1, 2008, and Dec 31, 2011, we recruited 30 patients. All patients underwent (111)In-DTPA-exendin-4 imaging, 25 patients underwent surgery (with histological analysis), and 27 patients were assessed with CT/MRI. (111)In-DTPA-exendin-4 SPECT/CT correctly detected 19 insulinomas and four additional positive lesions (two islet-cell hyperplasia and two uncharacterised lesions) resulting in a positive predictive value of 83% (95% CI 62-94). One true negative (islet-cell hyperplasia) and one false negative (malignant insulinoma) result was identified in separate patients by (111)In-DTPA-exendin-4 SPECT/CT. Seven patients (23%) were referred to surgery on the basis of (111)In-DTPA-exendin-4 imaging alone. For 23 assessable patients, (111)In-DTPA-exendin-4 SPECT/CT had a higher sensitivity (95% [95% CI 74-100]) than did CT/MRI (47% [27-68]; p=0·011). INTERPRETATION (111)In-DTPA-exendin-4 SPECT/CT could provide a good second-line imaging strategy for patients with negative results on initial imaging with CT/MRI. FUNDING Oncosuisse, the Swiss National Science Foundation, and UK Department of Health.