Direct comparison between cerebral oximetry by INVOS(TM) and EQUANOX(TM) during cardiac surgery: a pilot study.

INTRODUCTION: Several near-infrared spectroscopy oximeters are commercially available for clinical use, with lack of standardization among them. Accordingly, cerebral oxygen saturation thresholds for hypoxia/ischemia identified in studies conducted with INVOS(TM) models do not necessarily apply to other devices. In this study, the measurements made with both INVOS(TM) and EQUANOX(TM) oximeters on the forehead of 10 patients during conventional cardiac surgery are directly compared, in order to evaluate the interchangeability of these two devices in clinical practice. METHODS: Cerebral oxygen saturation measurements were collected from both INVOS(TM) 5100C and EQUANOX(TM) 7600 before anesthetic induction (baseline), two minutes after tracheal intubation, at cardiopulmonary bypass onset/offset, at aortic cross-clamping/unclamping, at the end of surgery and whenever at least one of the two devices measured a reduction in cerebral oxygen saturation equal to or greater than 20% of the baseline value. Bland-Altman analysis was used to compare the bias and limits of agreement between the two devices. RESULTS: A total of 140 paired measurements were recorded. The mean bias between INVOS(TM) and EQUANOX(TM) was -5.1%, and limits of agreement were ±16.37%. Considering the values as percent of baseline, the mean bias was -1.43% and limits of agreement were ±16.47. A proportional bias was observed for both absolute values and changes from baseline. CONCLUSIONS: INVOS(TM) and EQUANOX(TM) do not seem to be interchangeable in measuring both absolute values and dynamic changes of cerebral oxygen saturation during cardiac surgery. Large investigations, with appropriate design, are needed in order to identify any device-specific threshold.

Arthroscopic anatomy of the equine cervical articular process joints.

REASON FOR PERFORMING STUDY: Although arthropathy of the cervical articular process joints (APJs) is common, descriptions of the arthroscopic technique of the cervical APJ have not been reported previously. OBJECTIVES: To develop an arthroscopic approach to the APJ and to describe the arthroscopic anatomy of the APJ. STUDY DESIGN: Descriptive cadaver study and clinical case report. METHODS: The regional anatomy was reviewed and the technique developed on fresh cadaver necks. A series of cadaveric APJ arthroscopies from C2-C3 to C6-C7 were performed to evaluate the procedure, which was then used in 3 clinical cases. A description of the procedure and the potential complications encountered were recorded. RESULTS: The equine APJ consists of cranioventral and caudodorsal recesses; a single entry point at one of these recesses enables almost complete evaluation of cartilage surfaces and the synovial membrane and its villi. Successful entry into both APJ recesses was achieved in 22 cadaveric APJs and 5 APJs in the 3 clinical cases operated upon. An instrument portal was created to assess the feasibility of surgical arthroscopy. Complications were minor, and dissection of the APJs following the arthroscopic exploration revealed that the cartilage and periarticular neurovascular structures were not damaged during the procedure. CONCLUSIONS: This study shows that arthroscopic examination of the APJs of equine cervical vertebra is feasible and can be performed in mature horses. Arthroscopy of the APJs may provide additional diagnostic information compared to conventional diagnostic techniques.

Response of LaBr3(Ce) scintillators to 2.5 MeV fusion neutrons.

Measurements of the response of LaBr3(Ce) to 2.5 MeV neutrons have been carried out at the Frascati Neutron Generator and at tokamak facilities with deuterium plasmas. The observed spectrum has been interpreted by means of a Monte Carlo model. It is found that the main contributor to the measured response is neutron inelastic scattering on (79)Br, (81)Br, and (139)La. An extrapolation of the count rate response to 14 MeV neutrons from deuterium-tritium plasmas is also presented. The results are of relevance for the design of γ-ray diagnostics of fusion burning plasmas.

X-ray beam monitor made by thin-film CVD single-crystal diamond.

A novel beam position monitor, operated at zero bias voltage, based on high-quality chemical-vapor-deposition single-crystal Schottky diamond for use under intense synchrotron X-ray beams was fabricated and tested. The total thickness of the diamond thin-film beam monitor is about 60 µm. The diamond beam monitor was inserted in the B16 beamline of the Diamond Light Source synchrotron in Harwell (UK). The device was characterized under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of approximately 2 µm × 3 µm square. Time response, linearity and position sensitivity were investigated. Device response uniformity was measured by a raster scan of the diamond surface with the micro-focused beam. Transmissivity and spectral responsivity versus beam energy were also measured, showing excellent performance of the new thin-film single-crystal diamond beam monitor.

Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): evidence of phosphogypsum waste contamination.

Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore-offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE+Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE+Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE+Y concentrations (mean value 163.4 µg g(-1)) associated to high Th concentrations (mean value 7.9 µg g(-1)). Plot of shale-normalized REE+Y data of these coastal sediments showed Middle REE enrichments relative to Light REE and Heavy REE, manifested by a convexity around Sm-Gd-Eu elements. These anomalies in the fractionation patterns of the coastal sediments were attributed to phosphogypsum-contaminated effluents from an industrial plant, located in the southern Sicilian coast.

New developments in the diagnostics for the fusion products on JET in preparation for ITER (invited).

Notwithstanding the advances of the past decades, significant developments are still needed to satisfactorily diagnose "burning plasmas." D­T plasmas indeed require a series of additional measurements for the optimization and control of the configuration: the 14 MeV neutrons, the isotopic composition of the main plasma, the helium ash, and the redistribution and losses of the alpha particles. Moreover a burning plasma environment is in general much more hostile for diagnostics than purely deuterium plasmas. Therefore, in addition to the development and refinement of new measuring techniques, technological advances are also indispensable for the proper characterization of the next generation of devices. On JET an integrated program of diagnostic developments, for JET future and in preparation for ITER, has been pursued and many new results are now available. In the field of neutron detection, the neutron spectra are now routinely measured in the energy range of 1­18 MeV by a time of flight spectrometer and they have allowed studying the effects of rf heating on the fast ions. A new analysis method for the interpretation of the neutron cameras measurements has been refined and applied to the data of the last trace tritium campaign (TTE). With regard to technological upgrades, chemical vapor deposition diamond detectors have been qualified both as neutron counters and as neutron spectrometers, with a potential energy resolution of about one percent. The in situ calibration of the neutron diagnostics, in preparation for the operation with the ITER-like wall, is also promoting important technological developments. With regard to the fast particles, for the first time the temperature of the fast particle tails has been obtained with a new high purity Germanium detector measuring the gamma emission spectrum from the plasma. The effects of toroidal Alfven eigenmodes modes and various MHD instabilities on the confinement of the fast particles have been determined with a combination of gamma ray cameras, neutral particle analyzers, scintillator probe, and Faraday cups. From a more technological perspective, various neutron filters have been tested to allow measurement of the gamma ray emission also at high level of neutron yield.

Thermal neutron dosimeter by synthetic single crystal diamond devices.

We report on a new solid state dosimeter based on chemical vapor deposition (CVD) single crystal diamond fabricated at Roma "Tor Vergata" University laboratories. The dosimeter has been specifically designed for direct neutron dose measurements in boron neutron capture therapy (BNCT). The response to thermal neutrons of the proposed diamond dosimeter is directly due to (10)B and, therefore, the dosimeter response is directly proportional to the boron absorbed doses in BNCT. Two single crystal diamond detectors are fabricated in a p-type/intrinsic/metal configuration and are sandwiched together with a boron containing layer in between the metallic contacts (see Fig.1). Neutron irradiations were performed at the Frascati Neutron Generator (FNG) using the 2.5 MeV neutrons produced through the D(d,n)(3)He fusion reaction. Thermal neutrons were then produced by slowing down the 2.5 MeV neutrons using a cylindrical polymethylmethacrylate (PMMA) moderator. The diamond dosimeter was placed in the center of the moderator. The products of (10)B(n,alpha)Li nuclear reaction were collected simultaneously giving rise to a single peak. Stable performance, high reproducibility, high efficiency and good linearity were observed.

Performance of the UAB and the INFN-LNF Bonner sphere spectrometers in quasi monoenergetic neutron fields.

In the framework of collaboration between the Universidad Autónoma de Barcelona and the INFN Frascati National Laboratories, an experimental Bonner Sphere neutron spectrometry exercise has been performed in the 2.5 MeV and 14.2 MeV quasi monoenergetic neutron beams of the ENEA Fast Neutron Generator. The neutron spectra at given distances from the accelerator target have been determined, taking advantage of the new unfolding FRUIT code, recently developed by the LNF group. The results show a good coherence between the two spectrometers, and between the measured and simulated data.

Neutron spectrometry around a high-energy electron-positron collider using a multi-sphere system with passive detectors.

At the INFN LNF (Frascati), the 510 MeV electron-positron collider DAPhiNE is operating since 1997. The neutron fields in the areas around the accelerator were characterised using a Bonner sphere system. The sensitivity of the system was extended up to 10(2) MeV by means of a lead loaded 12('') sphere. Recently developed thermoluminescence dosemeters (TLDs), with improved neutron sensitivity and gamma rejection properties, were used as central detectors. The new TLD-based spectrometric system was characterised by irradiation in quasi-monoenergetic or radionuclide neutron fields. In addition, numerical verifications with the Monte Carlo code MCNP were performed. This work addresses this new TLD-based spectrometer and presents the spectral measurements performed in a point of test around DAPhiNE. The results are compared with those obtained, in the same point, with a previously validated Bonner sphere system based on an active (6)LiI(Eu) scintillator.

Inter-comparison among different TLD-based techniques in a standard multisphere assembly for the characterisation of neutron fields.

In the framework of collaboration among the ENEA Radiation Protection Institute (Bologna), the ENEA Fusion Department (Frascati) and the INFN-LNF-Radiation Protection Group (Frascati), an experimental campaign was organised on the usage of thermoluminescence dosemeters (TLDs) for the dosimetric and spectrometric characterisation of neutron fields. Commercially available TLDs of different material and different sensitivity to photons and thermal neutrons were selected, namely TLD600H and TLD700H from Harshaw, GR206 and GR207 from SSDML (China), MCP-6s from TLD Poland. The detectors were first calibrated in standard fields of photons ((60)Co) and thermal neutrons at the ENEA-IRP Secondary Standard Calibration Laboratory of Bologna, then exposed in fast neutron standard fields of different energy, using a standard multisphere moderating assembly. The paper compares the dosimetric characteristics of the studied TL detectors, underlining the (n-gamma) discrimination capability, and discusses their spectrometric performances addressed to radiation protection applications.

Neutron detection and dosimetry using polycrystalline CVD diamond detectors with high collection efficiency.

Polycrystalline chemical vapour deposited (CVD) diamond film is an interesting material for neutron detection and dosimetry. However, the use of CVD diamond detectors is still limited by the low-level signal pulse produced because of the high energy required to produce an electron-hole pair in diamond (13.2 eV) and by the reduced charge collection efficiency owing to several types of traps for electrons and holes in CVD films. A new type of CVD diamond detector with high gain (HG) contacts was produced as part of the collaboration between the ENEA Fusion Division and the Faculty of Engineering of Rome 'Tor Vergata' University. In this paper the performance of the HG CVD diamond detector is presented and possible applications of CVD diamond detectors to neutron dosimetry are also discussed.

Development and application of CVD diamond detectors to 14 MeV neutron flux monitoring.

CVD diamond is an interesting material for radiation detection, its atomic number (Z = 6) is close to that of soft tissues (Z = 7.1) and it can also work in harsh environments. Since many years CVD diamond films have been grown at the Faculty of Engineering, Rome 'Tor Vergata' University, and in 1998 a collaboration with ENEA Fusion Division was established to develop fast neutron monitors to be used in fusion tokamak environment. In this paper the first test of a 120 microm thick polycrystalline CVD diamond detector used for monitoring 14.7 MeV neutrons emission produced with the Frascati Neutron Generator (FNG) is reported. The detector operates in air and in pulse mode. The time irradiation profiles recorded with the CVD diamond detector were compared with those recorded by the standard monitors available at FNG (SSD, fission chamber, NE-213). Good stability and capability to operate in neutron flux up to 1.5 x 10(8) n cm(-2) s(-1) was observed. The radiation hardness property was also investigated using a 460 microm thick film and these results are also reported.

In phantom Dosimetric response of tooth enamel to neutrons.

Electron Paramagnetic Resonance dosimetry based on tooth enamel has one important application in dose reconstruction of nuclear plant workers, where the contribution of neutrons to individual dose is often important. Evaluation of tooth enamel response to neutrons is thus an important goal. A few experimental data at thermal and fast neutron energies are available. A first evaluation of the tooth enamel relative response to 60Co in monoenergetic neutron flux of 2.8 and of 14 MeV, published elsewhere, has provided results apparently non-consistent with the results obtained at lower and higher energies. A comparison of those results in the 2.8 and 14 MeV beams with those available in the literature for other beams is reported and possible reasons for incongruities are discussed. Dose conversion factors of enamel to the water and air are also calculated and reported.

Dosimetric response of tooth enamel to 14 Mev neutrons.

The electron paramagnetic resonance (EPR) response of tooth enamel in a monenergetic neutron beam of 14 MeV was studied, with the aim to evaluate the relative neutron to (60)Co sensitivity. Three samples of tooth enamel powder were irradiated in air. A whole tooth and a powdered sample were irradiated in a geometrical PMMA phantom, in order to simulate the real exposure of a tooth inside a human head. The measured dose in enamel was compared to the dose calculated by Monte Carlo simulation. The relative neutron to (60)Co sensitivity using different reference materials (air, water and enamel) was evaluated as well. Large differences in sensitivity values were found depending on the reference material: the obtained relative neutron to (60)Co sensitivity was 0.47+/-0.09 for enamel and 0.15+/-0.03 for water. A comparison with results in fast neutron fields is reported.

Energy dependence of TLD-300 response from 6 keV up to 1250 keV.

The energy dependence of the response function S(E), of CaF2:Tm (TLD-300) thermoluminescent material (3.2 x 3.2 x 0.90 mm3 ribbons) was measured from 6 keV up to 1250 keV (60Co) using 55Fe, 137Cs and 60Co gamma ray sources as well as X ray ISO reference beams. To the best knowledge of the authors the data for energies below 45 keV are reported for the first time. The S(E) function was also calculated in the energy range from 1 keV up to 20 MeV and compared with the experimental data relative to the total glow curve. The comparison shows good agreement from 1250 keV down to 40 keV. At lower energy the discrepancy increases. This is interpreted in terms of the X ray attenuation within the thickness of TLD-300. Finally, measurements point out the effects of different reading and annealing treatments on the measured function S(E).

Platinum levels in natural and urban soils from Rome and Latium (Italy): significance for pollution by automobile catalytic converter.

Platinum concentrations in topsoil samples collected in 1992 (48) and in 2001 (16) from the urban area of Rome have been determined by ICP-MS. Concentrations in 47 soil samples collected in 1992 from natural sites of Latium (an area around Rome) have been determined for a first assessment of natural background levels. The Pt concentrations in Rome urban soils collected in 1992 range from 0.8 to 6.3 ng/g (mean = 3.8 +/- 1.0) overlapping the concentration range of natural soils from Latium (mean = 3.1 +/- 2.1 ng/g). No significant correlation has generally been found between Pt contents in the 'natural' soils and related bedrock or major pedogenetic parameters. These results suggest that there is no evidence of Pt pollution in Rome urban soils at that time, because the massive use of the automobile catalytic converter has only just started. Higher (up to six times more) Pt concentrations, than those measured in the 1992 samples, have been measured, in some cases, in Rome urban soils collected in 2001, suggesting a possible start of Pt accumulation because of the large-scale use in the last decade of automobile catalytic converters. At the same time, a clear decrease of lead levels in Rome urban soils with respect to the levels measured in 1992 has been observed, paralleling the decreasing number of lead gasoline-fuelled cars. Here we present one of the first systematic studies for defining background levels of Pt in Italian natural soils, thus allowing for monitoring, in the future, should any possible Pt pollution caused by the use of automobile catalytic converter, especially in urban soils, occur.

Measurement of the mass attenuation coefficient for elemental materials in the range 6 < or = Z < or = 82 using X-rays from 13 up to 50 kev.

The mass attenuation coefficients for 22 high purity elemental materials (C, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Ta, Pt, Au, Pb) were measured in the X-ray energy range from 13 up to 50 keV using a high purity germanium detector with thin (50 microm) Be window and a variable-energy X-ray source. The measured values are compared with the theoretical ones obtained using the XCOM code and data base, as well as with other experimental data showing a general agreement within +/- 5%. The mass attenuation cross-sections were thus derived and compared with other experimental data available on the 1988 NBS database of X-ray attenuation cross-sections. The agreement is always within +/- 8%, but for a few points the discrepancies are up to +/- 18%. The data analysis has also shown that some measurements performed at 50.65 keV as well as at 36.65 keV are to be considered as new data for most of the measured materials.

Retromolar trigone tumors: evaluation by magnetic resonance imaging and correlation with pathological data.

The aim of this study was to evaluate the diagnostic accuracy of magnetic resonance (MR) images to establish both the T stage and the relationships between the tumors and the surrounding structures in retromolar trigone tumors. Twenty-two patients with squamous cell carcinoma of the retromolar trigone were examined by MR with a superconductive scanner operating at 1.5T. The study was performed with spin-echo (SE) T1 and T2 and short SE T1 sequences (TR 180 ms, TE 15 ms) after the administration of 0.2 mmol/kg of gadolinium-DTPA (Gd-DTPA). The mandible was studied with SE T1 weighted sequences and GE sequences. The results were compared with the pathological data on the T stage (TNM classification) and the involvement of the surrounding structures. A positive correlation was found in 19 of the 22 patients with an accuracy of 86%. In one patient, the lesion was classified as T1 by MR which, at surgery, resulted being T4, given the infiltration of the cortical mandible (this infiltration was too limited). In another, the MR showed a T4 lesion because of the presence of low signal intensity in the mandibular marrow with enhancement after the Gd-DTPA injection without cortical erosion, while pathological data revealed a T2 lesion (this signal intensity was secondary to inflammation). In another case, the lesion was classified as T1 by MR which, at surgery, proved to be a T2 lesion. In assessing the involvement of the surrounding structures. MR showed a high accuracy, specificity and sensitivity (> 90%). Five false positive cases were observed: in two because of infiltration of the masseter muscle and in the other three, because of infiltration to the pterigoid muscle, mandible and tonsillar bed, respectively, due to the close contact between the tumors and the surrounding structures. Only one false negative case was observed with infiltration of the mandibular marrow. In evaluating the low signal intensity of the mandibular marrow, the accuracy of MR was 87% the specificity 77% and the sensitivity 100%. In one case, perineural spread along the mandibular nerve was found. In conclusion, MR proved to be highly accurate to study the T stage and examine the relationships between the surrounding structures in cases of retromolar trigone tumors.

Measurement of the neutron sensitivity of TLD-300 irradiated in a tissue equivalent phantom by d(48.5) + Be neutrons.

The neutron sensitivities of the total response (kT) as well as of separate peaks 3 (k3) and 5 (k5) on the glow curve were measured for CaF2:Tm (TLD-300) thermoluminescent dosimeters. The TLD-300 were encapsulated in A-150 TE plastic and located at different depths in the water phantom. The phantom was irradiated with neutrons produced by the d(48.5) + Be reaction at the superconducting cyclotron of the Gershenson Radiation Oncology Center at Harper Hospital. A set of measurements, based on the use of a TE ionization chamber and Geiger-Müller (GM) counter was used to measure the neutron (Dn) and gamma (D gamma) dose at these locations. The neutron sensitivities of the TLDs were thus derived by comparison with the results obtained with the twin detector method. The average neutron sensitivities relative to gamma of the total response and the responses of single peaks 3 or 5 are 0.215 +/- 0.016, 0.126 +/- 0.010, and 0.357 +/- 0.014, respectively. A linear relationship was found between the ratio of the areas under peak 3 to that under peak 5 and the ratio of the gamma dose to the total dose.

[The magnetic resonance estimation of the T parameter in the staging of tumors of the oral cavity and tongue. A correlation with postoperative data and preliminary echotomographic experience]. / Valutazione con risonanza magnetica del parametro "T" nella stadiazione dei tumori della cavità orale e della lingua. Correlazione con i dati post-operatori e preliminare esperienza con ecotomografia.

Fifty-three patients with oral cavity and tongue tumors were studied with MRI, 18 with CT and 10 with US. MR results were compared with postoperative and clinical results relative to the T variable of the TNM classification of oral cavity tumors. MRI demonstrated 51 of 53 tumors; it was in agreement with surgery, relative to T, in 43 of 48 cases and with clinics in 5 of 5 cases. In 5 patients MRI understaged: two lesions were classified as T0 because the tumors developed on the surface (p T4, for alveolar ridge infiltration). Moreover, MRI staged another lesion as T2 instead of T3 because of its superficial component, while in 2 cases the infiltration of the cortical bone of the jaw was not demonstrated (T1 at MRI, T4 at p; T2 at MRI, T4 at p). MRI was reliable enough to evaluate the relationships between the lesions and the surrounding structures but it was limited in demonstrating superficial lesions and in evaluating the infiltration of the alveolar ridge and of the cortical bone of the jaw in the early stage. The use of gadolinium proved to be especially useful for the exact definition of the size of the lesions and of their relationships with the surrounding structures. CT proved better than MRI to evaluate bone involvement in one case, even though neither technique could identify bone involvement in another patient. US yielded accurate information on the presence of lesions, their size and relationships with midline and floor of the mouth muscles, while its demonstration of the relationships between tumors and bone structures was poor, especially relative to tumor spread outside the oral cavity.