The recent development of quinoline-based PET tracers that act as fibroblast-activation-protein inhibitors (FAPIs) demonstrated promising preclinical and clinical results. FAP is overexpressed by cancer-associated fibroblasts of several tumor entities. Here, we quantify the tumor uptake on 68 Ga-FAPI PET/CT of various primary and metastatic tumors to identify the most promising indications for future application. Methods: 68 Ga-FAPI PET/CT scans were requested by various referring physicians according to individual clinical indications that were considered insufficiently covered by 18 F-FDG PET/CT or other imaging modalities. All PET/CT was performed 1 h after injection of 122-312 MBq of 68 Ga-FAPI-04. We retrospectively identified 80 patients with histopathologically proven primary tumors or metastases or radiologically unequivocal metastatic lesions of histologically proven primary tumors. Tumor uptake was quantified by SUV max and SUV mean (60% isocontour). Results: Eighty patients with 28 different tumor entities (54 primary tumors and 229 metastases) were evaluated. The highest average SUV max (.12) was found in sarcoma, esophageal, breast, cholangiocarcinoma, and lung cancer. The lowest 68 Ga-FAPI uptake (average SUV max , 6) was observed in pheochromocytoma, renal cell, differentiated thyroid, adenoid cystic, and gastric cancer. The average SUV max of hepatocellular, colorectal, head-neck, ovarian, pancreatic, and prostate cancer was intermediate . SUV varied across and within all tumor entities. Because of low background in muscle and blood pool (SUV max , 2), the tumor-to-background contrast ratios were more than 3-fold in the intermediate and more than 6fold in the high-intensity uptake group. Conclusion: Several highly prevalent cancers presented with remarkably high uptake and image contrast on 68 Ga-FAPI PET/CT. The high and rather selective tumor uptake may open up new applications for noninvasive tumor characterization, staging examinations, or radioligand therapy. ://jnm.snmjournals.org/content/60/6/801 This article and updated information are available at: http://jnm.snmjournals.org/site/subscriptions/online.xhtml Information about subscriptions to JNM can be found at: http://jnm.snmjournals.org/site/misc/permission.xhtml

We consider an interferometer powered by laser light (a coherent state) into one input port and ask the following question: what is the best state to inject into the second input port, given a constraint on the mean number of photons this state can carry, in order to optimize the interferometer's phase sensitivity? This question is the practical question for high-sensitivity interferometry. We answer the question by considering the quantum Cramér-Rao bound for such a setup. The answer is squeezed vacuum.

The set of Bell-diagonal states for two qubits can be depicted as a tetrahedron in three dimensions. We consider the level surfaces of entanglement and quantum discord for Bell-diagonal states. This provides a complete picture of the structure of entanglement and discord for this simple case and, in particular, of their nonanalytic behavior under decoherence. The pictorial approach also indicates how to show that discord is neither convex nor concave.PACS numbers: 03.67.Mn, 03.65.Ud, 03.65.Yz Maintenance of quantum coherence is clearly important for quantum-information-processing protocols. Noise and decoherence, by turning pure states into mixed states, generally destroy quantum coherence. Efficient representation of quantum information requires that a quantum-information-processing system be composed of parts [1]. For multi-partite systems, quantum coherence is related to nonclassical correlations between the parts.One kind of nonclassical correlation is entanglement [2]. A pure quantum state is unentangled if it is a product of pure states for each part. A mixed state is unentangled (separable) if it can be written as an ensemble of such product states. Entanglement is the crucial resource for such quantum-information-processing protocols as quantum key distribution, teleportation, and super-dense coding [2].Operational measures of entanglement are notoriously difficult to calculate for mixed states; even the boundary between separability and entanglement is difficult to characterize. One can say, however, that the set of separable states is a convex set, is invariant under local unitary operations, and has dimension as large as the space of mixed states [2].Separable states have nonzero measure in the space of all states [3]. In a decoherence process that involves decay to a separable equilibrium state that does not lie on the boundary between separability and entanglement, the decohering state will cross that boundary before reaching the equilibrium state. This phenomenon, dubbed "sudden death of entanglement" [4,5], is the generic expectation in view of the geometry of separable states.Separable states can have nonclassical correlations even though they are unentangled. A state with only classical correlations, often called a classical state, is one that is diagonal in a product basis, for then the correlations are described by a joint probability distribution for classical variables of the parts. These purely classical states are a set of measure zero, as is suggested by the fact that any classical state can be perturbed infinitesimally to become nonclassical by making two of the eigenvectors infinitesimally entangled and is proved rigorously in [6].A variety of measures have been proposed to quantify nonclassical correlations for bipartite systems [7][8][9], in ways that can be nonzero for separable, but nonclassical states. Nonclassical, but perhaps separable correlations have been related to exponential speed-ups in the "power-of-one-qubit" model [10] of mixed-state quantum computation [11], but th...