First-principles design of nanostructured electrode materials for Na-ion batteries: challenges and perspectives.

Post-lithium batteries are emerging as viable solutions for sustainable energy transition. Effective deployment in the market calls for great research efforts in the identification of novel component materials and the assessment of related working principles. Computational modelling can be a key player in boosting innovation and development by enabling rational strategies for the design of appropriately tuned materials with optimized activity towards battery operating processes. By gaining access to the structural and electronic features of functional electrodes, state-of-the-art DFT methods can unveil the subtle structure-property relationship that affects the uptake, transport, and storage efficiency. Hereby, we aim at reviewing the research status of theoretical advances in the field of Na-ion batteries (NIBs) and illustrating to what extent atomistic insights into sodiation/desodiation mechanisms of nanostructured materials can assist the development of effective anodes and cathodes for stable and highly performing devices. Thanks to increasing computer power and fruitful cooperation between theory and experiments, the route for effective design methodologies is being paved and will feed the upcoming developments in NIB technology.

Sodium diffusion in ionic liquid-based electrolytes for Na-ion batteries: the effect of polarizable force fields.

Understanding the transport of sodium ions in ionic liquids is key to designing novel electrolyte materials for sodium-ion batteries. In this work, we combine molecular dynamics simulation and experiments to study how molecular interactions and local ordering affect relevant physico-chemical properties. Ionic transport and local solvation environments are investigated in electrolytes composed of sodium bis(fluorosulfonyl)imide, (Na[FSI]), in N,N-methylpropylpyrrolidinium bis(fluorosulfonyl)imide, [C3C1pyr][FSI], at different salt concentrations. The electrolyte systems are modelled by means of molecular dynamic simulations using a polarizable force field. We show that including polarization effects explicitly in the molecular simulations is required in order to attain a reliable description of the transport properties of sodium in the [C3C1pyr][FSI] electrolyte. The validation of the computational results upon comparison with experimental data allows us to assess the suitability of polarizable force fields in describing and interpreting the structure and dynamics of the sodium salt-ionic liquid system, which is essential to enable the application of IL-based electrolytes in novel energy-storage technologies.

A new mobile self-dispensing and administering system for 18F-FDG: evaluation of operator dose reduction.

PURPOSE: Recently new mobile systems for dispensing positron emitters have been produced, designed to guarantee dispensing cycles in an aseptic environment. The aim of the present work was to assess the advantage of one of these systems in radiation protection of operators in clinical settings. METHODS: Recently, in our centre the new self-dispensing system named KARL100 by Tema Sinergie was adopted for 18F-FDG radiopharmaceuticals. The system is associated with an automatic Rad-inject infuser. The system that was previously used was a fixed isolator NMC DSI (Tema Sinergie), equipped with a µDDS-An activity fractioning system, together with a pneumatic post for the syringe delivery. The dosimetric evaluations on both systems were carried out through environmental measurements with an ionisation chamber and with the use of personal dosimeters. RESULTS: The operations of preparation and administration of 18F-FDG dose to the patient, with the use of Karl100 + RadInject, involve exposures much lower than those obtained by the fixed isolator. The average body exposure of the technician was reduced by 31%, and for the physician by 77%. On the extremities, the equivalent dose to the hands of the technician was reduced by 78%, and for the physician by 96%. Also the additional dosimeters worn by the technician confirmed the estimated environmental assessments. CONCLUSIONS: The exposures of the working personnel were significantly reduced with the introduction of the new KARL100 system.

P2-Type Na0.84Li0.1Ni0.27Mn0.63O2-Layered Oxide Na-Ion Battery Cathode: Structural Insights and Electrochemical Compatibility with Room-Temperature Ionic Liquids.

Modern technologies that can replace state-of-the-art Li-ion batteries (LIBs), such as Na-ion batteries (NIBs), are currently driving new advancements in energy storage research. Developing functional active materials having sustainable features and enhanced performances able to assess their exploitation in the large-scale market represents a major challenge. Rationally designed P2-type layered transition metal (TM) oxides can enable high-energy NIB cathodes, where the tailored composition directly tunes the electrochemical and structural properties. Such positive electrodes need stable electrolytes, and exploration of unconventional room-temperature ionic liquid (RTIL)-based formulations paves the route toward safer options to flammable organic solvents. Notwithstanding the fact that Li+ doping in these materials has been proposed as a viable strategy to improve structural issues, an in-depth understanding of structure-property relationship as well as electrochemical testing with innovative RTIL-based electrolytes is still missing. Herein, we propose the solid-state synthesis of P2-Na0.84Li0.1Ni0.27Mn0.63O2 (NLNMO) cathode material, which exhibits promising structural reversibility and superior capacity retention upon cycling when tested in combination with RTIL-based electrolytes (EMI-, PYR14-, and N1114-FSI) compared to the standard NaClO4/PC. As unveiled from DFT calculations, lattice integrity is ensured by the reduced Jahn-Teller distortion upon Na removal exerted by Mn4+ and Li+ sublattices, while the good redox reversibility is mainly associated with the electrochemically active Ni2+/Ni3+/Ni4+ series burdening the charge compensation upon desodiation. By declaring the electrochemical compatibility of the P2-NLNMO cathode with three RTIL-based electrolytes and dissecting the role of Li/Ni/Mn sublattices in determining the electrochemical behavior, our comprehensive study enlightens the potential application of this electrode/electrolyte setup for future high-energy NIB prototype cells.

New Insights on Singlet Oxygen Release from Li-Air Battery Cathode: Periodic DFT Versus CASPT2 Embedded Cluster Calculations.

Li-air batteries are a promising energy storage technology for large-scale applications, but the release of highly reactive singlet oxygen (1O2) during battery operation represents a main concern that sensibly limits their effective deployment. An in-depth understanding of the reaction mechanisms underlying the 1O2 formation is crucial to prevent its detrimental reactions with the electrolyte species. However, describing the elusive chemistry of highly correlated species such as singlet oxygen represents a challenging task for state-of-the-art theoretical tools based on density functional theory. Thus, in this study, we apply an embedded cluster approach, based on CASPT2 and effective point charges, to address the evolution of 1O2 at the Li2O2 surface during oxidation, i.e., the battery charging process. Based on recent hypothesis, we depict a feasible O22-/O2-/O2 mechanisms occurring from the (112̅0)-Li2O2 surface termination. Our highly accurate calculations allow for the identification of a stable superoxide as local minimum along the potential energy surface (PES) for 1O2 release, which is not detected by periodic DFT. We find that 1O2 release proceeds via a superoxide intermediate in a two-step one-electron process or another still accessible pathway featuring a one-step two-electron mechanism. In both cases, it represents a feasible product of Li2O2 oxidation upon battery charging. Thus, tuning the relative stability of the intermediate superoxide species can enable key strategies aiming at controlling the detrimental development of 1O2 for new and highly performing Li-air batteries.

Structural Evolution of Air-Exposed Layered Oxide Cathodes for Sodium-Ion Batteries: An Example of Ni-doped NaxMnO2.

Sodium-ion batteries have recently aroused the interest of industries as possible replacements for lithium-ion batteries in some areas. With their high theoretical capacities and competitive prices, P2-type layered oxides (NaxTMO2) are among the obvious choices in terms of cathode materials. On the other hand, many of these materials are unstable in air due to their reactivity toward water and carbon dioxide. Here, Na0.67Mn0.9Ni0.1O2 (NMNO), one of such materials, has been synthesized by a classic sol-gel method and then exposed to air for several weeks as a way to allow a simple and reproducible transition toward a Na-rich birnessite phase. The transition between the anhydrous P2 to the hydrated birnessite structure has been followed via periodic XRD analyses, as well as neutron diffraction ones. Extensive electrochemical characterizations of both pristine NMNO and the air-exposed one vs sodium in organic medium showed comparable performances, with capacities fading from 140 to 60 mAh g-1 in around 100 cycles. Structural evolution of the air-exposed NMNO has been investigated both with ex situ synchrotron XRD and Raman. Finally, DFT analyses showed similar charge compensation mechanisms between P2 and birnessite phases, providing a reason for the similarities between the electrochemical properties of both materials.

Azobenzene-based optoelectronic transistors for neurohybrid building blocks.

Exploiting the light-matter interplay to realize advanced light responsive multimodal platforms is an emerging strategy to engineer bioinspired systems such as optoelectronic synaptic devices. However, existing neuroinspired optoelectronic devices rely on complex processing of hybrid materials which often do not exhibit the required features for biological interfacing such as biocompatibility and low Young's modulus. Recently, organic photoelectrochemical transistors (OPECTs) have paved the way towards multimodal devices that can better couple to biological systems benefiting from the characteristics of conjugated polymers. Neurohybrid OPECTs can be designed to optimally interface neuronal systems while resembling typical plasticity-driven processes to create more sophisticated integrated architectures between neuron and neuromorphic ends. Here, an innovative photo-switchable PEDOT:PSS was synthesized and successfully integrated into an OPECT. The OPECT device uses an azobenzene-based organic neuro-hybrid building block to mimic the retina's structure exhibiting the capability to emulate visual pathways. Moreover, dually operating the device with opto- and electrical functions, a light-dependent conditioning and extinction processes were achieved faithful mimicking synaptic neural functions such as short- and long-term plasticity.

First-Principles Study of Na Intercalation and Diffusion Mechanisms at 2D MoS2/Graphene Interfaces.

Na-ion batteries (NIBs) are emerging as promising energy storage devices for large-scale applications. Great research efforts are devoted to design new effective NIB electrode materials, especially for the anode side. A hybrid 2D heterojunction with graphene and MoS2 has been recently proposed for this purpose: while MoS2 has shown good reversible capacity as a NIB anode, graphene is expected to improve conductivity and resistance to mechanical stress upon cycling. The most relevant processes for the anode are the intercalation and diffusion of the large Na ion, whose complex mechanisms are determined by the structural and electronic features of the MoS2/graphene interface. Understanding these processes and mechanisms is crucial for developing new nanoscale anodes for NIBs with high performances. To this end, here we report a state-of-the-art DFT study to address (a) the structural and electronic properties of heterointerfaces between the MoS2 monolayers and graphene, (b) the most convenient insertion sites for Na, and (c) the possible diffusion paths along the interface and the corresponding energy barrier heights. We considered two MoS2 polymorphs: 1T and 3R. Our results show that 1T-MoS2 interacts more strongly with graphene than 3R-MoS2. In both cases, the best Na host site is found at the MoS2 side of the interface, and the band structure reveals a proper n-type character of the graphene moiety, which is responsible for electronic conduction. Minimum-energy paths for Na diffusion show very low barrier heights for the 3R-MoS2/graphene interface (<0.25 eV) and much higher values for its 1T counterpart (∼0.7 eV). Analysis of structural features along the diffusion transition states allows us to identify the strong coordination of Na with the exposed S atoms as the main feature hindering an effective diffusion in the 1T case. These results provide new hints on the physicochemical details of Na intercalation and diffusion mechanisms at complex 2D heterointerfaces and will help further development of advanced electrode materials for efficient NIBs.

d-Glucose Adsorption on the TiO2 Anatase (100) Surface: A Direct Comparison Between Cluster-Based and Periodic Approaches.

Titanium dioxide (TiO2) has been extensively studied as a suitable material for a wide range of fields including catalysis and sensing. For example, TiO2-based nanoparticles are active in the catalytic conversion of glucose into value-added chemicals, while the good biocompatibility of titania allows for its application in innovative biosensing devices for glucose detection. A key process for efficient and selective biosensors and catalysts is the interaction and binding mode between the analyte and the sensor/catalyst surface. The relevant features regard both the molecular recognition event and its effects on the nanoparticle electronic structure. In this work, we address both these features by combining two first-principles methods based on periodic boundary conditions and cluster approaches (CAs). While the former allows for the investigation of extended materials and surfaces, CAs focus only on a local region of the surface but allow for using hybrid functionals with low computational cost, leading to a highly accurate description of electronic properties. Moreover, the CA is suitable for the study of reaction mechanisms and charged systems, which can be cumbersome with PBC. Here, a direct and detailed comparison of the two computational methodologies is applied for the investigation of d-glucose on the TiO2 (100) anatase surface. As an alternative to the commonly used PBC calculations, the CA is successfully exploited to characterize the formation of surface and subsurface oxygen vacancies and to determine their decisive role in d-glucose adsorption. The results of such direct comparison allow for the selection of an efficient, finite-size structural model that is suitable for future investigations of biosensor electrocatalytic processes and biomass conversion catalysis.

Reorganization of a Nuclear Medicine Department in Northern Italy During a 2-Month Lockdown for COVID-19 Pandemic.

Coronavirus disease (COVID-19) outbreak has profoundly changed the organization of hospital activities. We present our experience of reorganization of a nuclear medicine service settled in Northern Italy during the pandemic period of March and April 2020 characterized a government-mandated lockdown. Our service remained open during the whole period, performing approximately 80% of the routine practice, while maintaining it COVID-free despite the geographical context characterized by a high risk of infection. Reorganization involved all aspects of a nuclear medicine department, following local, national, and international guidelines for prioritizing patients, telephone and physical triages, deployment of appropriate personal protective equipment, social distancing, and logistic changes for scheduling examinations and disinfection procedures. All staff remained COVID-19-negative despite the unintentional admission of 4 patients who later turned out to be positive for the severe acute respiratory syndrome coronavirus 2. These adopted measures would serve as the basis for safe nuclear medicine services in the post-lockdown phase.

First-principles study of Na insertion at TiO2 anatase surfaces: new hints for Na-ion battery design.

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs), chiefly for large-scale energy storage from renewables. Developing novel active materials is essential for the deployment of NIBs, especially in terms of negative electrodes that can accommodate the larger sodium ions. We focus on TiO2 anatase, which has been proposed as a promising anode material for the overall balance of performance, stability and cost. As the exposed crystal facets in different morphologies of nanostructured anatase can affect the electrochemical performances, here we report a theoretical investigation of Na+ adsorption and migration through (101), (100) and (001) surface terminations, thus explaining the different activities toward sodiation reported in the literature. Energy barriers computed by means of the CI-NEB method at the DFT+U level of theory show that the (001) surface is the most effective termination for Na+ insertion. We also provide a detailed analysis to elucidate that the energy barriers are due to structural modifications of the lattice upon sodiation. From these results we derive new design directions for the development of cheap and effective oxide-based nanostructured electrode materials for advanced NIBs.

Positron-emission tomography in gynaecologic malignancies.

INTRODUCTION: The role of (18)F-FDG PET in the management of gynaecologic malignancies remains unclear mainly due to the failure of clinicians to appreciate the significance of this imaging tool. However, this under utilisation is being actively re-addressed with a large number of reviews and studies, particularly in the last few years. METHODS AND RESULTS: PET has been shown to have high sensitivity and specificity in the evaluation of relapse and nodal disease in cervical cancer, while other uses such as staging and monitoring response to therapies being under further investigation. Similarly, promising results have been published in the use of PET in patients affected by endometrial cancer and uterine sarcomas for detecting lymph nodes metastasis and recurrent disease. In ovarian cancer, PET appears to have a great potential in staging and assessment of disease relapse. An important utility of PET in gynaecologic tumours, which is shared with a large number of other malignancies, is its value in positively changing the patients' management. CONCLUSION: The surge in studies using PET in gynaecological malignancies is in its early stages, and further studies are required to optimise the role of PET in these conditions.

Diagnosis of infected total knee arthroplasty with anti-granulocyte scintigraphy: the importance of a dual-time acquisition protocol.

OBJECTIVE: To evaluate clinical efficacy of a dual-time acquisition protocol consisting of early 4 h and delayed 20-24 h imaging with anti-granulocyte scintigraphy (LeukoScan) in the diagnosis of infection in painful total knee arthroplasty (TKA). MATERIALS AND METHODS: Seventy-eight consecutive patients with TKA (12 bilateral) were prospectively enrolled in the study from August 2004 to July 2005. All the patients had clinical and biochemical suspicious of infection, except for the 12 patients with bilateral painless prosthesis who had no signs and symptoms of loosening and/or infection and were considered as controls. TKA prostheses had been implanted 4 months to 9.5 years before our studies. Forty-three patients were on antibiotic therapy at the moment of scintigraphic examination, and treatment was not discontinued. All patients underwent LeukoScan examination by performing both early 4 h and delayed 20-24 h imaging. In addition to planar imaging SPECT was performed in 18 cases. A decrease in radiotracer uptake from early to delayed LeukoScan imaging was interpreted as an unspecific finding (negative for infection), while an increasing uptake was interpreted as a positive finding for the presence of infection. Three-phase Tc-MDP bone scan was also routinely performed by standard technique. Sensitivity and specificity of early and delayed LeukoScan imaging were calculated. RESULTS: Sensitivity for early and delayed imaging were 92.7%, while specificity was 78.4% for early imaging and 100% for delayed imaging approach. SPECT imaging did not add any significant information as regard to specificity in our experience. Eight false positive early scans were correctly diagnosed as negative at delayed imaging. Three false negative results were recorded. Sensitivity and specificity were similar when patients were on or off antibiotic therapy. Imaging was negative in all 12 controls. CONCLUSIONS: Our results, based on a large group of patients, suggest that delayed LeukoScan imaging is important in identifying false positive results detect at early imaging. Thus, a dual-time, 4 h early and 20-24 h delayed LeukoScan imaging approach should be recommended to increase the diagnostic accuracy of the scintigraphy, with the exception of patients with a negative early LeukoScan examination, in whom the acquisition of delayed imaging appears unnecessary. In our experience, concomitant antibiotic therapy did not influence the diagnostic value of LeukoScan.

Antigranulocyte scintigraphy in infected hip prosthesis: the diagnostic importance of delayed 20-24-h imaging and semiquantitative analysis.

AIM: To evaluate clinical efficacy of a dual-time acquisition protocol, which included 4 and 20/24-h imaging with antigranulocyte antibody scintigraphy (LeukoScan) combined with semiquantitative analysis in the diagnosis of infection in painful hip prosthesis. METHODS: Sixty-seven consecutive patients with hip prosthesis were enrolled in this research project: 35 females, 32 males, mean age of 56.3 years. All patients had clinical and biochemical suspicious of infection. Each prosthesis had been implanted 3 months to 12 years before enrollment in this study. Twenty-four patients were on antibiotic therapy at the time of scintigraphy. Seven patients had bilateral hip prosthesis, one painful and the other painless: the seven painless prostheses were considered controls. LeukoScan examination was performed both at early (4 h) and delayed (20/24 h) times. The scintigraphic data were assessed both by visual and semiquantitative methods by three experienced nuclear medicine physicians blinded to clinical, laboratory and radiographic results. The uptake was graded visually by a 4-point scale: intense=3, moderate=2, mild=1 and absent=0. The semiquantitative analysis was obtained by a region of interest (ROI) analysis used in the anterior views to measure the ratio between the mean radioactivity in the prosthesis and the background radioactivity in the early and delayed images. An increase in the intensity of uptake of at least one scale-step at visual analysis and 20% at semiquantitative ROI analysis at the dual-time (early vs. delayed) LeukoScan was considered consistent with infection, whereas a stable or decreasing pattern was judged a negative result. Three-phase 99mTc-hydroxymethane diphosphonate bone scan was also performed routinely. Final diagnosis was determined at surgery and/or long-term clinical and imaging follow-up. RESULTS: At visual analysis, sensitivity for both early and delayed imaging was 94%, whereas specificity was 71% for early imaging and 83% for early and delayed imaging approach. At semiquantitative ROI analysis, sensitivity remained 94%, whereas specificity rose slightly to 73% for early imaging and to 90% for early and delayed imaging combined. Of note, four false-positive early scans were diagnosed correctly as negative on delayed imaging showing a decreasing pattern in uptake intensity. Sensitivity and specificity were similar whether patients were on or off antibiotic therapy. CONCLUSION: Our data show that early imaging LeukoScan is highly sensitive in evaluating septic prosthesis, but it is not optimally specific. Although the dual-time LeukoScan is capable of significantly increasing specificity for detecting infection. The semiquantitative ROI analysis further increased the specificity. Concomitant antibiotic treatment did not seem to influence the diagnostic efficacy of LeukoScan scintigraphy in detecting infected hip prosthesis.

Reconstruction parameters for 111In-pentetreotide SPECT: variability with respect to body weight and body region.

UNLABELLED: This study, which was based on a large series of consecutive patients imaged by (111)In-pentetreotide SPECT for a neuroendocrine tumor, evaluated variability in reconstruction parameters in relation to patient body weight and the body region imaged, looking for the possibility of standardizing such parameters. METHODS: One hundred twenty-four patients underwent (111)In-pentetreotide scintigraphy: 4- and 24-h whole-body and planar scans and a 24-h SPECT examination. All patients were injected with 140-150 MBq of (111)In-pentetreotide at least 1 wk after somatostatin analogs had been discontinued. SPECT images were systematically acquired at the levels of the head, chest, and abdomen. SPECT was performed using a dual-head gamma-camera with medium-energy collimators, step-and-shoot method, no circular orbit, a 64 x 64 matrix, and 30 s per view for a total of 64 views. Two reconstruction procedures were compared: the iterative method using 10 iterations and the filtered backprojection method using a Butterworth filter with different cutoffs and orders. RESULTS: Optimal SPECT images were obtained by applying the Butterworth filter. The reconstruction parameters could be standardized for the head and chest but were more variable for the abdomen, mainly because (111)In-pentetreotide is physiologically trapped in different intestinal areas and varies over time, especially in the liver, spleen, bowel, and urinary tract. CONCLUSION: Filtered backprojection using a Butterworth filter appears adequate for standardizing the reconstruction parameters for (111)In-pentetreotide SPECT of the head and chest. Processing of abdominal images is more operator-dependent. A 150-MBq dose of (111)In-pentetreotide is recommended when planning multiple SPECT acquisitions in the same patient.

Ab initio study of PbCr(1-x)S x O4 solid solution: an inside look at Van Gogh Yellow degradation.

Van Gogh Yellow refers to a family of lead chromate pigments widely used in the 19th century and often mixed with lead sulfate to obtain different yellow hues. Unfortunately, some paintings, such as the famous Sunflowers series, suffered degradation problems due to photoactivated darkening of once bright yellow areas, especially when irradiated with UV light. Recent advanced spectroscopic analyses have proved that this process occurs mostly where the pigment presents a sulfur-rich orthorhombic phase of a PbCr(1-x)S x O4 solid solution, while chromium-rich monoclinic phases are lightfast. However, the question of whether degradation is purely a surface phenomenon or if the bulk properties of sulfur-rich pigments trigger the process is still open. Here, we use first-principles calculations to unveil the role of sulfur in determining important bulk features such as structure, stability, and optical properties. From our findings, we suggest that degradation occurs via an initial local segregation of lead sulfate that absorbs at UV light wavelengths and provides the necessary energy for subsequent reduction of chromate ions into the greenish chromic oxide detected in experiments. In perspective, our results set reliable scientific foundations for further studies on surface browning phenomena and can help to chose the best strategy for the proper conservation of art masterpieces.

Optimized protocol for (18)F-choline PET/CT in patients with biochemically relapsed prostate cancer: experiences on 250 consecutive cases.

PURPOSE: We review acquisition F-choline PET/CT methodology, evaluate a new F-choline acquisition protocol for prostate cancer (PC), and propose a standardized acquisition protocol on F-choline in PC patients. MATERIALS: Two hundred fifty consecutive PC patients (mean age 72 years, mean PSA 7.9 ng/mL) were prospectively evaluated with F-choline PET/CT. An early scan of the pelvis (1 bed position of 4 minutes) was followed by a whole-body scan at 1 hour. Early and 1 delayed hour images of the pelvis were compared. RESULTS: Twenty-one percent of patients (n = 57) with positive F-choline demonstrated abnormal local uptake; 18% of patients (n = 45) showed distant localization only; 23% of patients (n = 53) had both local and distant localization; 38% of patients (n = 38) did not show any pathological uptake. All early images showed absence of radioactive urine in ureters, bladder, or urethra with satisfactory visualization of the prostatic region. Considering the group of patients with local uptake only, the prostatic region uptake, confirmed by late images, was better visualized in the early phase in 32/57 cases (SUVmax 12.4 ± 3.2 vs. 7.3 ± 5.2, P <0.01). Instead distant lesions were visualized on both early and late images with similar uptakes values (SUVmax 9.8 ± 4.1 vs. 10.3 ± 4.5, P = N.S.). CONCLUSION: Early F-choline images improve pelvic prostate cancer lesion clarity. All pathologic pelvic deposits (prostate, lymph nodes, bone) were visualized both in the early and late images.

New acquisition protocol of 18F-choline PET/CT in prostate cancer patients: review of the literature about methodology and proposal of standardization.

PURPOSE: (1) To evaluate a new acquisition protocol of (18)F-choline (FCH) PET/CT for prostate cancer patients (PC), (2) to review acquisition (18)F-choline PET/CT methodology, and (3) to propose a standardized acquisition protocol on FCH PET/CT in PC patients. MATERIALS: 100 consecutive PC patients (mean age 70.5 years, mean PSA 21.35 ng/mL) were prospectively evaluated. New protocol consisted of an early scan of the pelvis immediately after the injection of the tracer (1 bed position of 4 min) followed by a whole body scan at one 1 hour. Early and 1 hour images were compared for interfering activity and pathologic findings. RESULTS: The overall detection rate of FCH PET/CT was 64%. The early static images of the pelvis showed absence of radioactive urine in ureters, bladder, or urethra which allowed a clean evaluation of the prostatic fossae. Uptake in the prostatic region was better visualized in the early phase in 26% (7/30) of cases. Other pelvic pathologic findings (bone and lymph nodes) were visualized in both early and late images. CONCLUSION: Early (18)F-choline images improve visualization of abnormal uptake in prostate fossae. All pathologic pelvic deposits (prostate, lymph nodes, and bone) were visualized in both early and late images.