TOFPET ASIC for PET applications

A 64-channel ASIC for Time-of-Flight Positron Emission Tomography (TOF PET) imaging has been designed and simulated. The circuit is optimized for the readout of signals pro- duced by the scintillation of a L(Y)SO crystal optically coupled to a silicon photomultiplier (SiPM). Developed in the framework of the EndoTOFPET-US collaboration (1), the ASIC is integrated in the external PET plate and performs timing, digitization and data transmission for 511 keV and lower-energy events due to Compton scattering. Multi-event buffering capability allows event rates up to 100 kHz per channel. The channel cell includes a low input impedance low-noise current conveyor and two trans-impedance amplifier branches separately optimized for energy and time resolution. Two voltage mode discriminators generate respectively a fast trigger for accurate timing and a signal for time-over-threshold calcu- lation, used for charge measurement. The digitization of these signals is done by two low-power TDCs, providing coarse and fine time stamps that are saved into a local register and later managed by a global controller, which builds-up the 40-bit event data and runs the interface with the data acquisition back-end. Running at 160 MHz the chip yields a 50 ps time binning and dissipates u 7 mW per channel (simulated for 40 kHz event rate p/channel) for high capacitance photodetectors (9 mm 2 active area Silicon Photomultiplier with 320 pF terminal capacitance). The minimum SNR of 23.5 dB expected with this capacitance should allow triggering on the first photoelectron to achieve the envisaged timing performance for a TOF-PET system

A family presenting with multiple endocrine neoplasia type 2B: A case report

<p>Abstract</p> <p>Introduction</p> <p>Multiple endocrine neoplasia 2B, a rare autosomal dominant syndrome, is characterized by early onset of medullary thyroid carcinoma, pheochromocytoma, marfanoid habitus and mucosal neuromas of the tongue, lips, inner cheeks and inner eyelids. Gangliomatosis of the gastrointestinal tract and its complications may also occur in patients with this disease.</p> <p>Case presentation</p> <p>We present the case of a 16-year-old Persian man diagnosed as having a non-invasive form of multiple endocrine neoplasia 2B (medullary thyroid cancer, mucosal neuroma of the tongue, lips and inner eyelids). Our patient, who had a positive family history of medullary thyroid cancer, was of normal height with no signs of marfanoid habitus.</p> <p>Conclusions</p> <p>Ophthalmological and oral manifestations of multiple endocrine neoplasia 2B, as in the case of our patient, are rare presentations of the disease; unfortunately in the case of our patient his condition had not been noted and acted upon until he presented to our department. The diagnosis in our patient's case was made only after his mother presented with the same condition. As a result, we emphasize that physicians should pay more attention to the oral and ocular signs of multiple endocrine neoplasia 2B in order to diagnose this fatal syndrome at an earlier phase.</p

A multinodular goiter as the initial presentation of a renal cell carcinoma harbouring a novel VHL mutation

BACKGROUND: Secondary involvement of the thyroid gland is rare. Often the origin of the tumor is difficult to identify from the material obtained by fine-needle aspiration cytology. Renal cell carcinoma of the clear-cell type is one of the more common carcinomas to metastasize to the thyroid gland. Somatic mutations of the von Hippel-Lindau tumor suppressor gene are associated with the sporadic form of this tumor. We aimed to illustrate the potential utility of DNA based technologies to search for specific molecular markers in order to establish the anatomic site of origin. CASE PRESENTATION: A 54-yr-old Caucasian male complaining of a rapidly increasing neck tumor was diagnosed as having a clear-cell tumor by fine-needle aspiration cytology. A positive staining for cytokeratin as well as for vimentin and CD10 in the absence of staining for thyroglobulin, calcitonin and TTF1 suggested a renal origin confirmed by computed tomography. Using frozen RNA, obtained from cells left inside the needle used for fine needle aspiration cytology, it was possible to identify a somatic mutation (680 delA) in the VHL gene. CONCLUSION: In the presence of a clear-cell tumor of the thyroid gland, screening for somatic mutations in the VHL gene in material derived from thyroid aspirates might provide additional information to immunocytochemical studies and therefore plays a contributory role to establish the final diagnosis. Moreover, in a near future, this piece of information might be useful to define a targeted therapy

Development of ClearPEM-Sonic, a multimodal mammography system for PET and Ultrasound

International audience; ClearPEM-Sonic is an innovative imaging device specifically developed for breast cancer. The possibility to work in PEM-Ultrasound multimodality allows to obtain metabolic and morphological information increasing the specificity of the exam. The ClearPEM detector is developed to maximize the sensitivity and the spatial resolution as compared to Whole-Body PET scanners. It is coupled with a 3D ultrasound system, the SuperSonic Imagine Aixplorer that improves the specificity of the exam by providing a tissue elasticity map. This work describes the ClearPEM-Sonic project focusing on the technological developments it has required, the technical merits (and limits) and the first multimodal images acquired on a dedicated phantom. It finally presents selected clinical case studies that confirm the value of PEM information

Mediterranean cork oak savannas require human use to sustain biodiversity and ecosystem services

9 páginas, 5 figuras, 2 tablas.Mediterranean cork oak savannas, which are found only in southwestern Europe and northwestern Africa, are ecosystems of high socioeconomic and conservation value. Characterized by sparse tree cover and a diversity of understory vegetation - ranging from shrub formations to grasslands - that support high levels of biodiversity, these ecosystems require active management and use by humans to ensure their continued existence. The most important product of these savannas is cork, a non-timber forest product that is periodically harvested without requiring tree felling. Market devaluation of, and lower demand for, cork are causing a decline in management, or even abandonment, of southwestern Europe's cork oak savannas. Subsequent shrub encroachment into the savanna's grassland components reduces biodiversity and degrades the services provided by these ecosystems. In contrast, poverty-driven overuse is degrading cork oak savannas in northwestern Africa. "Payment for ecosystem services" schemes, such as Forest Stewardship Council (FSC) certification or Reducing Emissions from Deforestation and Degradation and enhancement of carbon stocks (REDD+) programs, could produce novel economic incentives to promote sustainable use and conservation of Mediterranean cork oak savanna ecosystems in both Europe and Africa.We thank C Fontaine, S Cerasoli, C Moura, R Jackson, R Ryel, L Silva, D Porej, and HM Pereira for helpful comments that greatly improved the manuscript. Funding was provided by CREOAK project (EU R&D Fund project number QLK5-CT-2002-01596) and Portuguese National Science Foundation projects POCTI/AGG/48704/2002, POCI/AGR/63322/2004, and PTDC/AGR-AAM/098790/2008.Peer reviewe

Aerosol optical properties from columnar data during the second Aerosol Characterization Experiment on the south coast of Portugal

Measurements of aerosol optical properties over the atmospheric column (aerosol optical thickness, spectral angular sky radiance (sky brightness), and downwelling hemispheric flux) have been used to derive climate-relevant aerosol parameters such as the phase function, the broadband single-scattering albedo, and the refractive index. These parameters are needed to estimate the direct short-wave radiative forcing by aerosols and to validate aerosol models in the satellite retrieval algorithms. Values of the broadband single-scattering albedo obtained in this study range between w0 = 0.98 (marine aerosols) and 0.90 (continental pollution aerosols). The columnar ambient broadband refractive index is found to be m = 1.39 ± 0.044 i (<0.003) for marine conditions and m = 1.48 ± 0.058 i (0.01 ± 0.003) for polluted continental aerosols. Nonsphericity is shown to be important in the case of marine aerosols. Moreover, aerosol nonsphericity gives an additional contribution to the negative short-wave radiative forcing of marine aerosols under clear-sky conditions, which can be estimated as being 30 up to 50% of the radiative forcing estimated for spherical marine aerosols. In the case of continental polluted aerosols the optical properties can be represented by spherical particles, and no additional shape effect has to be considered. However, the aerosol absorption leads to an increase of about 40% of the radiative forcing estimated for nonabsorbing aerosol of the same size distribution