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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.

Resumen Objetivo El cancer de mama es un problema de salud en todo el mundo, con altas tasas de incidencia y mortalidad. Es bien sabido que el desarrollo de metodos de diagnostico mas sensibles y especificos es de gran importancia, ya que un diagnostico precoz es esencial para tratar con exito los tumores. Lapachol es un compuesto natural, perteneciente al grupo de la naftoquinona, que se ha utilizado ampliamente en la medicina tradicional para tratar diversas enfermedades, incluido el cancer. El objetivo de este estudio fue evaluar el lapachol marcado con tecnecio 99m (99mTc) como una sonda de imagenes para la identificacion del cancer de mama. Metodos Para lograr este proposito, el lapachol se marco con 99mTc, se determino la pureza radioquimica y la estabilidad in vitro. Tambien se evaluo el aclaramiento en sangre en ratones sanos y la biodistribucion en ratones con tumor 4T1. Resultados Lapachol fue exitosamente marcado con 99mTc, con altos valores de rendimiento radioquimico (95,9 ± 3,4%). La estabilidad in vitro mostro que el complejo radiomarcado permanecio estable hasta 24 h, con valores superiores al 90% tanto para solucion salina como para plasma (95,6 ± 3,6% y 96,4 ± 1,7%, respectivamente). El complejo radiomarcado decae de forma bifasica, con una vida media de distribucion y eliminacion igual a 3,3 y 50,0 min, respectivamente. La biodistribucion y las imagenes gammagraficas mostraron una alta captacion en los organos de excrecion (rinones, higado e intestino). Tambien se puede observar que la captacion tumoral fue mayor que en el musculo en todos los puntos temporales. La relacion de tumor/musculo alcanza ∼4,5 a las 24 h despues de la administracion. Conclusion Estos hallazgos indican que 99mTc-lapachol puede ser un potencial agente de diagnostico para los tumores de mama.

Aim Breast cancer is a health problem worldwide with high incidence and mortality rates. It is well known that the development of more sensitive and specific diagnostic methods is of great importance since an early diagnosis is essential to successfully treat tumors. Lapachol is a natural compound, belonging to the naphthoquinone group that has been widely used in traditional medicine to treat various illnesses, including cancer. The aim of this study was to evaluate technetium-99m-labeled lapachol as an imaging probe for breast cancer identification. Methods To achieve this purpose, lapachol was labeled with technetium-99m, radiochemical purity and in vitro stability were determined. Blood clearance, in healthy mice, and biodistribution, in 4T1 tumor-bearing mice, were also evaluated. Results Lapachol was successfully labeled with technetium-99m, with high values of radiochemical yield (95.9 ± 3.4%). In vitro stability showed that the radiolabeled complex remained stable for up to 24 h, with values above 90% for both saline and plasma (95.6 ± 3.6% and 96.4 ± 1.7%, respectively). The radiolabeled complex decays in a biphasic manner, with a half-life of distribution and elimination equal to 3.3 and 50.0 min, respectively. Biodistribution and scintigraphic images showed high uptake in organs of excretion (kidneys, liver, and intestine). It could be also noted that tumor uptake was higher than the muscle at all time points. Tumor-to-muscle ratio reaches ∼4.5 at 24 h after administration. Conclusion These findings suggest that 99mTc-Lapachol can be a potential diagnostic agent for breast tumors.

Results obtained with a new, very compact detector for imaging with a matrix of leak microstructures (LM) are reported. Spatial linearity and spatial resolution obtained by scanning and the detection of alpha particles with 100% efficiency, when compared with a silicon detector, are stressed. Preliminary results obtained in detecting single electrons emitted by the heated filament (Ec &lt, 1 eV) at 1–3 mbar of propane are reported.

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.Recently, in our centre the new self-dispensing system named KARLThe operations of preparation and administration ofThe exposures of the working personnel were significantly reduced with the introduction of the new KARL

Liposomes are lipid vesicles widely used as nanocarriers in targeted drug delivery systems for therapeutic and/or diagnostic purposes. A strategy to prolong the blood circulation time of the liposomes includes the addition of a hydrophilic polymer polyethylene glycol (PEG) moiety onto the surface of the vesicle. Several studies claim that liposome PEGylation by a single chain length or a combination of PEG with different chain lengths may alter the liposomes’ pharmacokinetic properties. Therefore, the purpose of this study was to evaluate the influence of PEG on the biodistribution of pH-sensitive liposomes in a tumor-bearing animal model. Three liposomal formulations (PEGylated or not) were prepared and validated to have a similar mean diameter, monodisperse distribution, and neutral zeta potential. The pharmacokinetic properties of each liposome were evaluated in healthy animals, while the biodistribution and scintigraphic images were evaluated in tumor-bearing mice. High tumor-to-muscle ratios were not statistically different between the PEGylated and non-PEGylated liposomes. While PEGylation is a well-established strategy for increasing the blood circulation of nanostructures, in our study, the use of polymer coating did not result in a better in vivo profile. Further studies must be carried out to confirm the feasibility of the non-PEGylated pH-sensitive liposomes for tumor treatment.

Painful osseous metastasis resulting from castration-resistant prostate carcinoma is a common clinical problem. Historically, nuclear medicine offered several palliative beta-emitting radiopharmaceuticals targeting the skeleton with the goal of decreasing pain. However, these have largely been replaced by the alpha-emitting agent 223radium (Ra). 223Ra received Food and Drug Administration approval in 2013 for the treatment of metastatic castration-resistant prostate cancer with symptomatic bone metastases without visceral metastases. 223Ra offers an improved therapeutic profile due to its alpha-particle emissions resulting in a relatively higher linear energy transfer and lower particle range compared with beta-emitters. 223Ra also has demonstrated to increase overall survival in patients and to delay adverse skeletal events. Running a successful clinical nuclear therapy program with Ra requires a multidisciplinary team approach and this article suggests an implementation strategy from the authors' institution. Potential new nuclear radiopharmaceuticals still under investigation offering the future possibility of radioligand therapy are also discussed briefly.

Sentinel lymph node biopsy (SNB) in patients with papillary thyroid carcinoma (PTC) and negative for clinically neck lymph node metastatic involvement (N0) has emerged as a promising minimally invasive procedure to detect metastatic nodes. The MEDLINE database was searched via the PubMed interface on 10 January 2018 for the MeSH headings “sentinel lymph node biopsy” and “thyroid carcinoma”. Vital blue dye, radioisotope, and the combination of both techniques are used in PTC patients. These methods and the emerging role of SPECT/CT are discussed in this review. The sentinel lymph node (SLN) identification rates ranged from 0 to 100% for blue dye, 83 to 100% for radioisotopes, and 66 to 100% for the combination of both techniques, respectively. SNB based on radioisotope technique with the use of intraoperative gamma-probe is an accurate and safe method that allows the highest SLN detection rate. There is sufficient evidence to propagate the increasing use of SNB procedure that has the potential to avoid prophylactic lymph node surgery in patients clinically N0.

This 16-year-old boy presented with acute retrosternal pain possibly representing acute myocardial infarction. Cardiac enzymes were within reference ranges. There were marked increases in metanephrine to 3299 μg/24 h (reference

PURPOSE FDG PET/CT has a recognized high predictive power to assess the response to neoadjuvant chemoradiation therapy (CRT) in patients affected by locally advanced rectal cancer (LARC), but a relatively high number of false-positive findings decrease its specificity: with the aim to solve this problem, a new method of imaging analysis is here proposed. METHODS The new method here described, named Biological target volume (BTV) Overlapping Segmentation System (BOSS), has been applied on 24 consecutive patients with LARC that were all previously classified as nonresponders to CRT by means of the response index criterion that is adopted in our center. The BOSS method is based on the quantification of the amount of superimposition between pretreatment and posttreatment BTV. All BTVpre was down using a threshold of 60% of SUVmax in the tumor (BTV60). The results (overlap volumes and percentage of overlap volumes) were then matched up with postoperative pathology classified by the Mandard's tumor regression grade (TRG) system. RESULTS Eleven patients were classified as responders (TRG1-2) and 13 as nonresponders (TRG 3-5). Among all the results obtained by BOSS method, only the percentage of overlap volume data between BTV60 and BTVpost (%Over_60) was able to correctly distinguish between responders and nonresponders. In our experience, a cutoff of 56% on the %Over_60 provided the best results in terms of true negative (11 cases), true positive (12 cases), false negative (1 case), and false positive (none). CONCLUSIONS This new method, we developed, appears able to unmask the false-positive cases, improving the specificity of FDG PET/CT to predict the response to CRT patients with LARC.

PURPOSE: To evaluate if the detection rate (DR) of (18)F-choline (18F-CH) PET/CT is influenced by androgen-deprivation therapy (ADT) in patients with prostate cancer (PC) already treated with radical intent and presenting biochemical relapse. MATERIALS AND METHODS: We have retrospectively evaluated (18)F-CH PET/CT scans of 325 consecutive PC patients enrolled in the period November 2009 to December 2012 previously treated with radical intent and referred to our centre to perform (18)F-CH PET/CT for biochemical relapse. Two different groups of patients were evaluated. group A included the whole sample of 325 patients (mean age 70 years, range: 49-86) who presented trigger PSA between 0.1 and 80 ng/ml (mean 5.5 ng/ml), and group B included 187 patients (mean age 70 years, range 49-86) with medium-low levels of trigger PSA ranging between 0.5 and 5 ng/ml (mean PSA 2.1 ng/ml); group B was chosen in order to obtain a more homogeneous group of patients in terms of PSA values also excluding both very low and very high PSA levels avoiding the "a priori" higher probability of negative or positive PET scan, respectively. At the time of examination, 139 patients from group A and 72 patients from group B were under ADT: these patients were considered to be hormone-resistant PC patients because from their oncologic history (>18 months) an increase of PSA levels emerged despite the ongoing ADT. The relationship between (18)F-CH PET/CT findings and possible clinical predictors was investigated using both univariate and multivariate binary logistic regression analyses, including trigger PSA and ADT. RESULTS: Considering the whole population, overall DR of (18)F-CH PET was 58.2 % (189/325 patients). In the whole sample of patients (group A), both at the univariate and multivariate logistic regression analysis, trigger PSA and ADT were significantly correlated with the DR of (18)F-CH PET (p

PURPOSE: This study aims to evaluate the role of (11)C-choline PET/CT in patients with biochemical relapse after radical prostatectomy (RP) showing prostate-specific antigen (PSA) values lower than 0.5 ng/mL. METHODS: We performed (11)C-choline PET/CT in 71 consecutive patients previously treated with RP showing PSA values lower than 0.5 ng/mL. (11)C-Choline PET/CT was performed following standard procedure. (11)C-Choline PET/CT-positive findings were validated by transrectal ultrasonography + biopsy, repeated (11)C-choline PET/CT, other conventional imaging modality, and histology. RESULTS: (11)C-Choline PET/CT was true positive in 15/71 (21.1%). (11)C-Choline uptake was observed in pelvic lymph nodes (7/71; 9.9%), in the prostatic bed (7/71; 9.9%), and in bone (1/71; 1.4%). Mean PSA, PSA doubling time (PSAdt), and PSA velocity (PSAvel) values ± SD in (11)C-choline PET/CT-positive patients was 0.37 ± 0.1 ng/mL, 3.4 ± 2.1 months, and 0.05 ± 0.1 ng/mL/yr, respectively. (11)C-Choline PET/CT was false negative in 2 patients and false positive in 1 patient. Among all variables, only PSAdt and the ongoing hormonal treatment were statistically significant in the prediction of a positive (11)C-choline PET/CT at multivariate analysis. CONCLUSIONS: (11)C-Choline PET/CT could be used early after biochemical failure even if PSA values are very low, preferentially in hormonal resistant patients showing fast PSA kinetics. An early detection of the site of relapse could lead to a personalized and tailored treatment.

Background Proton Magnetic Resonance Spectroscopy (1H MRS) is used for clinical diagnosis in some tumours. The aim of this study is to explore ex vivo the potential of 1H MRS in identifying malignancy through metabolic markers in the perspective of its application in all cases of difficult diagnosis and after neoadjuvant treatment. Methods Spectroscopy was performed ex vivo on 29 colorectal specimens. All patients were staged with imaging, underwent radical surgery and then followed-up. Spectral quantification analysis of components expressed in colorectal tumours and in healthy mucosa were evaluated. The MRS-tumour marker (MRS-tm) was calculated for each case. The U-test was used to compare MRS-tm in tumours and in healthy mucosa. In order to select a cut-off for MRS-tm in the tumour and healthy mucosa and to distinguish patients who were disease-free or with recurrence-progression, we performed the ROC curve analysis. Results In the 24 subjects without neoadjuvant treatment, it was found that MRS-tm is able to discriminate healthy and neoplastic tissue and can discriminate patients with risk of recurrence/progression Conclusion Our data seem to show that 1H MRS may be successfully applied in vivo non-invasively to differentiate tumours from healthy mucosa and could also distinguish patients with different prognoses.

Secondary hyperparathyroidism (sHPT) is a major complication for patients with end-stage renal disease on long-term hemodialysis or peritoneal dialysis. When the disease is resistant to medical treatment, patients with severe sHPT are typically referred for parathyroidectomy (PTx), which usually improves biological parameters as well as clinical signs and symptoms. Unfortunately, early surgical failure with persistent disease may occur in 5%-10% of patients and recurrence reaches 20%-30% at 5 years. Presently, the use of parathyroid scintigraphy in sHPT is usually limited to the management of surgical failures after initial PTx. This review describes the strengths and limitations of typical (99m)Tc-sestamibi imaging protocols, and highlights the potential benefits of using parathyroid scintigraphy in the initial workup of surgical patients.

Purpose The estimated prevalence of cryptorchidism in young males is close to 2%. In oncological PET/CT studies, it might be difficult to recognize false-positive 18 FDG uptake due to an ectopic testis. Materials and methods In this pilot study, we report on three patients with lymphoma referred for assessment of response to treatment and in whom cryptorchidism was not known at the time of 18 FDG-PET/CT imaging. Results In each of these patients, moderate 18 FDG uptake corresponding to an ovoid mass in the inguinal canal was (or could has been) misinterpreted as a lymphoma-involved inguinal lymph node. Clues to avoid misinterpretation are discussed. Conclusion Moderate 18 FDG uptake in ectopic testes represents a potential source of false-positive at initial staging or evaluation of therapeutic response of lymphomas and other malignancies that needs to be recognized.

It is well known the useful role of ¹⁸F-FDG-PET/CT for differential diagnosis between benign and malignant disease, for staging, for monitoring response and for prognosis regarding mesothelioma. Recently, literature was enriched with new interesting studies regarding the potential applications of ¹⁸F-FDG-PET/CT in this field. The purpose of this review is to evaluate articles published on line (PubMed) from January 2011 until October 2012 in order to obtain an overview of recent progress of molecular imaging in malignant mesothelioma. The main topics concern the use of ¹⁸F-FDG-PET/CT in radiation therapy planning, monitoring of treatment (surgery/chemotherapy) response and prognosis assessment.

This review article is focused on the role of FDG-PET/CT in visualizing atherosclerosis and on the relevance of inflammatory cells such as macrophages and T-lymphocytes in the formation of the atherosclerotic plaque. The vulnerability of the inflammatory plaque and the risk derived from the provocation of cardio- and cerebrovascular incidents independently from the presence of stenotic vessels are discussed as well as the evolution toward calcified plaque. The important role of FDG-PET/CT in early diagnosis of inflammatory plaque is discussed in both animal studies and in clinical setting. The possibility of curing inflammatory plaques, type of drugs, and the possibility of monitoring the anti-inflammatory treatment by FDG-PET/CT are also discussed.

Purpose The aims of the study were (a) to evaluate the diagnostic role, by means of positive detection rate (PDR), of 18F-choline (CH) positron emission tomography (PET)/CT in patients with prostate cancer treated with radiotherapy, with curative intent, and suspicion of relapse during follow-up, (b) to correlate the PDR with trigger prostate-specific antigen (PSA), (c) to investigate the possible influence of androgen deprivation therapy (ADT) at the time of scan on PDR and (d) to assess distribution of metastatic spread.

PURPOSE: Acute infective endocarditis is a potentially life-threatening disease. Its outcome strongly depends on systemic embolization and extracardiac infections. When present, these conditions usually lead to a more aggressive therapeutic approach. However, the diagnosis of peripheral septic embolism is very challenging. (18)F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT has proven to be accurate for the detection of inflammatory diseases and occult infections. The aim of this study was to assess the added value of (18)F-FDG PET/CT in the detection of extracardiac embolisms in the evaluation of patients with suspected valvular endocarditis (VE). METHODS: Seventy-one patients with suspected infective endocarditis, enrolled between June 2010 and December 2012, underwent (18)F-FDG PET/CT with the standard procedure on a dedicated PET/CT scanner. Extracardiac findings were subsequently evaluated with other imaging procedures. RESULTS: Of the 71 patients with suspicion of infective endocarditis, we found unexpected extracardiac findings in 17 patients (24 \%) without any clinical suspicion. Extracardiac findings were subsequently evaluated with other imaging procedures. CONCLUSION: PET/CT detected unexpected extra sites of infection in 24 \% of cases, leading to changes in therapeutic management in a very relevant percentage of patients. These findings may have important therapeutic implications.

The high incidence and mortality of breast cancer supports efforts to develop innovative imaging probes to effectively diagnose, evaluate the extent of the tumor, and predict the efficacy of tumor treatments while concurrently and selectively delivering anticancer agents to the cancer tissue. In the present study we described the preparation of technetium–99 m (99mTc)-labeled paclitaxel (PTX) and evaluated its feasibility as a radiotracer for breast tumors (4T1) in BALB/c mice. Thin Layer Chromatography (TLC) was used to determine the radiochemical purity and in vitro stability of 99mTc-PTX. PTX micelles showed a unimodal distribution with mean diameter of 13.46 ± 0.06 nm. High radiochemical purity (95.8 ± 0.3%) and in vitro stability (over than 95%), up to 24 h, were observed. Blood circulation time of 99mTc-PTX was determined in healthy BALB/c mice. 99mTc-PTX decays in a one-phase manner with a half-life of 464.3 minutes. Scintigraphic images and biodistribution were evaluated at 4, 8 and 24 h after administration of 99mTc-PTX in 4T1 tumor-bearing mice. The data showed a significant uptake in the liver, spleen and kidneys, due to the importance of these routes for excretion. Moreover, high tumor uptake was achieved, indicated by high tumor-to-muscle ratios. These findings indicate the usefulness of 99mTc-PTX as a radiotracer to identify 4T1 tumor in animal models. In addition, 99mTc-PTX might be used to follow-up treatment protocols in research, being able to provide information about tumor progression after therapy.

The aim of this study was to correlate qualitative visual response and various PET quantification factors with the tumour regression grade (TRG) classification of pathological response to neoadjuvant chemoradiotherapy (CRT) proposed by Mandard.Included in this retrospective study were 69 consecutive patients with locally advanced rectal cancer (LARC). FDG PET/CT scans were performed at staging and after CRT (mean 6.7 weeks). Tumour SUVmax and its related arithmetic and percentage decrease (response index, RI) were calculated. Qualitative analysis was performed by visual response assessment (VRA), PERCIST 1.0 and response cut-off classification based on a new definition of residual disease. Metabolic tumour volume (MTV) was calculated using a 40 % SUVmax threshold, and the total lesion glycolysis (TLG) both before and after CRT and their arithmetic and percentage change were also calculated. We split the patients into responders (TRG 1 or 2) and nonresponders (TRG 3-5).SUVmax MTV and TLG after CRT, RI, ΔMTV% and ΔTLG% parameters were significantly correlated with pathological treatment response (p0.01) with a ROC curve cut-off values of 5.1, 2.1 cm(3), 23.4 cm(3), 61.8 %, 81.4 % and 94.2 %, respectively. SUVmax after CRT had the highest ROC AUC (0.846), with a sensitivity of 86 % and a specificity of 80 %. VRA and response cut-off classification were also significantly predictive of TRG response (VRA with the best accuracy: sensitivity 86 % and specificity 55 %). In contrast, assessment using PERCIST was not significantly correlated with TRG.FDG PET/CT can accurately stratify patients with LARC preoperatively, independently of the method chosen to interpret the images. Among many PET parameters, some of which are not immediately obtainable, the most commonly used in clinical practice (SUVmax after CRT and VRA) showed the best accuracy in predicting TRG.

Purpose The aim of this study is to explore the feasibility of 11C-Choline PET in the assessment of the degree of inflammation in the Chlamydia muridarum genital infection model. Procedures Forty female Balb/c mice received 2.5 mg of medroxyprogesterone acetate i.m. 9 and 2 days prior to the infection: 21 mice were infected by C. muridarum into the vaginal vault, 12 mice were treated with inactivated chlamydiae, and 7 mice were SPG buffer-treated as negative controls. Three healthy control mice were not treated with progesterone. Mice in each category were randomly subdivided in two groups: (1) sacrificed at 5, 10, 15, and 20 days for histological analysis and (2) undergoing 11C-Choline PET at days 5, 10, and 20 post-infection (20 MBq of 11C-Choline, uptake time of 10 min, acquisition through a small-animal PET tomograph for 15 min). Results Infected animals showed a significantly higher standardized uptake value than both controls and animals inoculated with heat-inactivated chlamydiae in each PET scan (P

In recent years, hand-held mini γ-cameras have been increasingly used to perform scintigraphic imaging during surgery. The aim of the present work was to evaluate the physical characteristics of a new high-sensitivity hand-held mini γ-camera through specific phantom measurements. To characterize the performances of the imaging probe Guardian2 hand-held γ-camera, we measured its sensitivity and depth transmission curve, the extrinsic spatial resolution and spatial linearity, the spatial uniformity, and the count-rate linearity. We also estimated its whole image quality through the contrast-to-noise ratio of four hot spheres (internal diameters ranging from 4.9 to 9.8 mm). The sensitivity of the imaging probe Guardian2 γ-camera was 204 counts/s/MBq; it had a high spatial resolution (2.5 mm FWHM at contact) and optimal linearity of counts (Pearson's coefficient, R=0.999). The integral uniformity was 12.0% in the useful field of view (FOV) and 8.8% in the central FOV, whereas the differential uniformity was 5.7% in the useful FOV and 4.0% in the central FOV. The system was able to detect and distinguish all four small spheres used for the whole quality test. The contrast-to-noise ratio was evaluated both at contact with the collimator and with a 5-cm-thick interposed Plexiglas slab. The γ-imaging probe that we evaluated demonstrated good performance, confidently allowing its use for specific clinical applications in radio-guided surgery.

To assess the addition value of ¹⁸F-Fluorodeoxyglucose (FDG) PET/computed tomography (FDG-PET/CT) vs. CT in detecting early metastatic deposits in bone marrow (BM).From January 2009 to December 2010, 198 consecutive patients (88 male, 110 female; median age: 64 years) were retrospectively examined. All patients underwent ¹⁸F-FDG-PET/CT for disease evaluation: 65 for lung cancer, 66 for breast cancer, 57 for lymphoma and 10 for multiple myeloma. All scans were reviewed by a radiologist and a specialist in nuclear medicine for the identification of bone lesions. The presence of BM metastases was confirmed by biopsy, sequential PET/CT scan or magnetic resonance imaging when available. A patient-based analysis was performed.Investigating the presence of skeletal metastasis, 94 (48%) patients had positive and 104 (52%) negative CT scan whereas 110 (56%) had positive and 88 (44%) negative FDG-PET/CT scan (P0.001). The two imaging modalities were concordant in 178 (90%) patients for bone lesions; on the contrary 20 (10%) patients had discordant results (P0.001). In 21 out of 178 concordant patients BM lesions were identified both in CT and FDG-PET, whereas nine out of the 20 discordant patients showed BM involvement at PET/CT only. Overall, PET/CT was able to identify 30 (15%) patients with BM lesions. In these latter patients, the maximum standardized uptake value (SUVmax) for BM metastases was 7.9±4.5 (range: 3.1-19.0), resulting slightly higher in patients with negative than positive CT scan (8.3±5.1 vs. 7.8±4.3, respectively; P=0.79).FDG-PET/CT resulted more accurate than CT in early detection of BM metastases. The FDG-PET/CT images improve the staging of about 15% of our study population. PET/CT detected BM lesions mainly on the basis of their increased metabolic activity rather than on anatomical alterations. Moreover, it provided an accurate identification of tumour viability that was useful for treatment planning and follow-up.

In this paper, a new methodological approach to using PET information in radiotherapy treatment planning has been discussed. Computed tomography (CT) represents the primary modality to plan personalized radiation treatment, because it provides the basic electron density map for correct dose calculation. If PET scanning is also performed it is typically coregistered with the CT study. This operation can be executed automatically by a hybrid PET/CT scanner or, if the PET and CT imaging sets have been acquired through different equipment, by a dedicated module of the radiotherapy treatment planning system. Both approaches have some disadvantages: in the first case, the bore of a PET/CT system generally used in clinical practice often does not allow the use of certain bulky devices for patient immobilization in radiotherapy, whereas in the second case the result could be affected by limitations in window/level visualization of two different image modalities, and the displayed PET volumes can appear not to be related to the actual uptake into the patient. To overcome these problems, at our centre a specific procedure has been studied and tested in 30 patients, allowing good results of precision in the target contouring to be obtained. The process consists of segmentation of the biological target volume by a dedicated PET/CT console and its export to a dedicated radiotherapy system, where an image registration between the CT images acquired by the PET/CT scanner and a large-bore CT is performed. The planning target volume is contoured only on the large-bore CT and is used for virtual simulation, to individuate permanent skin markers on the patient.

A 62-year-old man presented with persistent fever, weakness, and retrosternal pain 3 years after aortic valve bioprosthesis (AVR). His white blood cell count was 11,000/μL and C-reactive protein was 13.6 mg/dL. Consecutive blood cultures isolated Staphylococcus epidermidis and capitis. Transesophageal echocardiography demonstrated small aortic valve prosthesis vegetation. F-FDG PET/CT revealed prominent AVR activity, SUVmax = 12.2. He was treated with daptomycin, meropenem, and gentamicin for 1 month and followed by daptomycin and carbapenem for 3 months. Follow-up F-FDG PET/CT at 6 months demonstrated complete clearing of AVR activity associated with full asymptomatic recovery.

State of the art point-spread function (PSF) corrections implemented in positron emission tomography/computed tomography (PET/CT) reconstruction improved image quality and diagnostic performance but caused an increase in the standardized uptake value (SUV) compared to a conventional OSEM reconstruction system. The EANM suggested one produce two reconstructions, one optimised for maximum lesion detection and one for semi-quantitative analysis. In this work we investigated an alternative methodology, using a single reconstruction data set together with a post-reconstruction algorithm for SUV harmonization. Data acquisition was performed on a Siemens Biograph mCT system equipped with lutetium oxyorthosilicat crystals, PSF and time-of-flight algorithms and on a General Electric Discovery STE system equipped with BGO crystals. Both a EANM double reconstruction method and a dedicated post-reconstruction algorithm (marketed as EQ-filter) were tested to harmonize the quantitative values of the two PET/CT scanners. For phantom measurements we used a NEMA IQ phantom and a Jaszczak cylindrical phantom equipped with small spheres (lesion to background ratios of 8:1 and 4:1). Several different reconstruction settings were tested in order to provide a general methodology. Data obtained by phantom measurements were validated on seven oncologic patients who performed a one-bed extra acquisition on a different scanner. The evaluation regarded 39 small lesions (diameters: 0.3-2.6 cm) and was performed by two experienced nuclear medicine physicians. The SUV recoveries measured with the PSF reconstruction exceeded those obtained by the OSEM reconstruction with deviations ranging from 16% to 150%. These discrepancies resulted below 7% applying the optimized value of the EQ.filter or the double-reconstruction methods. For each reconstruction setting the optimal value of the EQ.filter was identified in order to minimize these discrepancies. Patient data, analyzed by Wilcoxon statistical test, confirmed and validated phantom measurements. EQ.filter can harmonize SUV values between different PET/CT scanners using a single reconstruction optimized to maximum lesion detectability. In this way, the second reconstruction proposed by EANM/EARL is avoided.

A 76-year-old woman was referred to our centre to perform (18)F-FDG PET/CT with the clinical suspicion of vasculitis. Whole body PET was negative for vasculitis but it depicted moderate hypermetabolism in several lymph nodes of the mediastinum and intense uptake of the tracer in the parotid glands. Since the patient referred skin lesion on both legs a particular acquisition of the lower extremities was performed which showed diffuse uptake on the perimalleolar region of both legs. On the basis of the PET/CT findings that were suggestive for sarcoidosis the patient performed bronchoalveolar lavage (BAL) and biopsy of a mediastinal lymph node which confirmed the suspicion of sarcoidosis.

Nuclear medicine imaging of endocrine disorders takes advantage of unique cellular properties of endocrine organs and tissues that can be depicted by targeted radiopharmaceuticals. Detailed functional maps of biodistributions of radiopharmaceutical uptake can be displayed in three-dimensional tomographic formats, using single photon emission computed tomography (CT) that can now be directly combined with simultaneously acquired cross-sectional anatomic maps derived from CT. The integration of function depicted by scintigraphy and anatomy with CT has synergistically improved the efficacy of nuclear medicine imaging across a broad spectrum of clinical applications, which include some of the oldest imaging studies of endocrine dysfunction.

PURPOSE The aim of this study was to correlate PERCIST criteria and a new criterion developed in our center that we named PREDIST (PET Residual Disease in Solid Tumor) with tumor regression grade (TRG) classification of pathologic response to neoadjuvant chemoradiotherapy (CRT) in patients affected by rectal cancer. METHODS Seventy-three consecutive patients affected by locally advanced rectal cancer (LARC) were retrospectively included. FDG-PET/CT scans were performed at staging time and after the end of CRT (mean time 6.5 weeks). The analysis was performed by PERCIST criteria 1.0 and PREDIST criteria based on a new definition of residual disease. We split the TRG system into responders (TRG1-2) and nonresponders (TRG3-5). Pearson chi-square analysis by cross-tabulations was performed. RESULTS PREDIST classification was statistically predictive of TRG response (P = 0.004, sensitivity 81.8% and specificity 54.9%). On the contrary, PERCIST criteria was not statistically correlated to TRG (P = 0.128) caused by a very low specificity (9.8%). CONCLUSIONS FDG-PET/CT scan is an accurate tool to predict preoperatively the response to CRT in LARC patients. The novel proposed criterion (PREDIST) seems to be helpful to discriminate responder by nonresponder patients.

The estimated prevalence of cryptorchidism in young males is close to 2%. In oncological PET/CT studies, it might be difficult to recognize false-positive ¹⁸FDG uptake due to an ectopic testis.In this pilot study, we report on three patients with lymphoma referred for assessment of response to treatment and in whom cryptorchidism was not known at the time of ¹⁸FDG-PET/CT imaging.In each of these patients, moderate ¹⁸FDG uptake corresponding to an ovoid mass in the inguinal canal was (or could has been) misinterpreted as a lymphoma-involved inguinal lymph node. Clues to avoid misinterpretation are discussed.Moderate ¹⁸FDG uptake in ectopic testes represents a potential source of false-positive at initial staging or evaluation of therapeutic response of lymphomas and other malignancies that needs to be recognized.

Limbic encephalitis is one of the most common paraneoplastic neurological syndromes, which is mostly associated with small cell lung cancer, testicular tumors, and breast cancer. F-FDG PET/CT can have an important role both in the identification of limbic encephalitis itself and in the detection of the unknown malignancy that might have caused it. We report a case of a 57-year-old female patient with paraneoplastic limbic encephalitis, confirmed both by MRI and F-FDG PET/CT, and the concurrent identification of an unknown lung malignancy by whole-body PET/CT.

The aims of the study were (a) to evaluate the diagnostic role, by means of positive detection rate (PDR), of ¹⁸F-choline (CH) positron emission tomography (PET)/CT in patients with prostate cancer treated with radiotherapy, with curative intent, and suspicion of relapse during follow-up, (b) to correlate the PDR with trigger prostate-specific antigen (PSA), (c) to investigate the possible influence of androgen deprivation therapy (ADT) at the time of scan on PDR and (d) to assess distribution of metastatic spread.¹⁸F-CH PET/CT exams from 46 consecutive patients (mean age 71.3 years, range 51-84 years) with prostate cancer (mean Gleason score 6.4, range 5-8) previously treated by definitive radiotherapy and with suspicion of relapse with negative or inconclusive conventional imaging were retrospectively evaluated. Of the 46 patients, 12 were treated with brachytherapy and 34 with external beam radiation therapy. Twenty-three patients were under ADT at the time of the examination. Trigger PSA was measured within 1 month before the exam (mean value 6.5 ng/ml, range 1.1-49.4 ng/ml). Patients were subdivided into four groups according to their PSA level: 1.0PSA ≤ 2.0 ng/ml (11 patients), 2.0PSA ≤ 4.0 ng/ml (16 patients), 4.0PSA ≤ 6.0 ng/ml (9 patients) and PSA6.0 ng/ml (10 patients). Correlation between ADT and PDR was investigated as well as between PSA and distribution of metastatic spread.The overall PDR of ¹⁸F-CH PET/CT was 80.4% (37/46 patients), increasing with the increase of trigger PSA. PDR of ¹⁸F-CH PET/CT is not influenced by ADT (p = 0.710) even if PET performed under ADT demonstrated an overall higher PDR (82.6%). The majority of the patients (59%, 22/37 patients) showed local relapse only, confined to the prostatic bed; 22% of the PET/CT-positive patients (8/37 patients) showed distant relapse only (bone localizations in all of them), while the remaining 19% (7/37 patients) showed both local and distant (lymph node and bone) spread.¹⁸F-CH PET/CT showed a high overall detection rate (80%), proportional to the trigger PSA (both for local and distant relapse) not influenced by ADT. ¹⁸F-CH PET/CT is proposed as a first-line imaging procedure in restaging prostate cancer patients primarily treated with radiotherapy.

Acute infective endocarditis is a potentially life-threatening disease. Its outcome strongly depends on systemic embolization and extracardiac infections. When present, these conditions usually lead to a more aggressive therapeutic approach. However, the diagnosis of peripheral septic embolism is very challenging. (18)F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT has proven to be accurate for the detection of inflammatory diseases and occult infections. The aim of this study was to assess the added value of (18)F-FDG PET/CT in the detection of extracardiac embolisms in the evaluation of patients with suspected valvular endocarditis (VE).Seventy-one patients with suspected infective endocarditis, enrolled between June 2010 and December 2012, underwent (18)F-FDG PET/CT with the standard procedure on a dedicated PET/CT scanner. Extracardiac findings were subsequently evaluated with other imaging procedures.Of the 71 patients with suspicion of infective endocarditis, we found unexpected extracardiac findings in 17 patients (24%) without any clinical suspicion. Extracardiac findings were subsequently evaluated with other imaging procedures.PET/CT detected unexpected extra sites of infection in 24% of cases, leading to changes in therapeutic management in a very relevant percentage of patients. These findings may have important therapeutic implications.

Introduction Gastrointestinal stromal tumours (GISTs) represent a major fraction of gastrointestinal sarcomas, frequently showing c-kit exon 11 mutations and associated with a good response to imatinib mesylate. Secondary resistance to imatinib has also been reported during therapy; therefore, clinicians need non-invasive tools for early assessment of treatment response due to traditional morphologic criteria [X-rays and computerized tomography (CT)] being unsuccessful. We report upon a patient with GIST with exon 11 mutation showing excellent response to imatinib mesylate, only a few days after initiation of the therapy and persisting for 18 months of follow-up. Here we also provide a short review of the recent literature on this topic. Conclusion There is evidence that F-FDG PET and PET/CT could be used to optimally monitor c-kit inhibitor therapy in GISTs, detecting early responders, non-responders and secondary resistance, there by allowing better patient management. Introduction Gastrointestinal stromal tumours (GISTs) are rare malignancies even though they represent the most relevant part of the gastrointestinal (GI) tract sarcomas. In most cases, GISTs are localized in the stomach and small intestine, followed by the colon and rectum1. GISTs are derived from Cajal cells in myenteric plexus; they are frequently marked by the expression of the c-kit tyrosine kinase receptor1. C-kit is a tyrosine kinase and is normally activated as a ligand by stem cell factor; a mutation of the c-kit proto-oncogene activates the tyrosine kinase in the absence of physiologic stimulation, there by leading to unrestrained cell proliferation2. The majority of GISTs (75%–80%) shows gain-of-function mutations of transmembrane receptor c-kit, which causes continuous activation of cell proliferation. The most common is the exon 11 mutation3. Genetic mutation analysis allows investigation of the relationship between the mutations occurred and response to drugs, such as imatinib mesylate. Imatinib mesylate is a tyrosine kinase inhibitor of tumour growth, and it has been demonstrated to be effective in GIST treatment. It is currently the first-line drug in advanced GISTs4. Recent studies3,5 show that 85% patients with c-kit exon 11 mutation respond to imatinib mesylate; nevertheless, it has been reported that resistance to this drug may occur during therapy6. This phenomenon needs to be disclosed as early as possible to change the therapeutic strategy, improve the clinical outcome and reduce the cost of ineffective therapies. In this regard, the response evaluation criteria in solid tumours (RECIST) criteria which relates to morphological examinations, mainly contrastenhanced computed tomography (CT), are unsatisfactory in assessment of GISTs response because changes in tumour size may be minimal at an early post-therapy evaluation or the lesion could be even larger because of intra-tumoural necrosis or haemorrhage7,8. There is recent evidence that a functional imaging modality such as 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) or a hybrid imaging modality such as PET/ CT could achieve this goal9–11. This paper reports the case of a GIST patient treated with imatinib mesylate and showing an excellent response as documented by 18F-FDG PET/CT only a few days after initiation of the therapy and persisting for 18 months of follow-up. We also reviewed the relevant literature pertaining to the response monitoring tools in GISTs. Discussion In April 2008, a 54-year-old male patient underwent surgery for GIST T2N0M0 with mutation of exon 11. In August 2010, a controlled CT revealed bone and liver GIST metastasis that was proven at biopsy. Therapy with imatinib mesylate was scheduled. Before initiating therapy, the patient underwent baseline 18F-FDG PET/CT and repeated an early PET/CT examination 10 days after initiation of the therapy. Subsequent PET/CT controls during imatinib mesylate therapy * Corresponding author Email: domenico.rubello@libero.it † Current address: Nuclear Medicine and Radiology Unit, Morgagni-Pierantoni Hospital, Forli, Italy 1 Department of Nuclear Medicine, Medical Physics, Radiology, Neuroradiology, PET/ CT Centre, ‘Santa Maria della Misericordia’ Hospital, Via Tre Martiri 140, 45100 Rovigo, Italy 2 Department of Medical Physics, ‘Santa Maria della Misericordia’ Hospital, Rovigo, Italy 3 Department of Oncology, ‘Santa Maria della Misericordia’ Hospital, Rovigo, Italy Em er gi ng T ec hn ol og ie s

PURPOSE This study aimed to assess the feasibility and potential usefulness of a new intraoperative portable high-resolution imaging γ-camera for the localization of sentinel lymph node in patients with breast cancer. METHODS Sixteen T1 to T2 breast cancer female patients were evaluated (mean age, 62 years) with preoperative lymphoscintigraphy, acquired 30 minutes after intradermal injection of 60 to 70 MBq (1.6-1.9 mCi) of (99m)Tc-nanocolloids in saline volumes of 0.1 to 0.2 mL. Surgery took place the day after (18-20 hours after tracer injection). For intraoperative sentinel lymph node localization, a traditional γ-probe was used by the surgeon. Moreover, a portable imaging γ-camera was used by the nuclear physician who was present in the operating room. RESULTS The portable imaging γ-camera showed very high spatial resolution (2.4 mm) in the 4.4 × 4.4 cm(2) FOV, with a good sensitivity of 180 cps/MBq at a Plexiglas depth of 1 cm. In 11 patients, lymphoscintigraphy, γ-probe, and imaging γ-camera depicted the same number of radioactive lymph nodes (17 nodes; 5 of which were metastatic and detected in 6 different patients). In 6 patients, the portable imaging γ-camera detected 1 node more than lymphoscintigraphy (in total, 5 nodes more), one of which was metastatic (the only one metastatic in that patient). CONCLUSIONS Our preliminary results showed that a portable high-resolution hand-held imaging γ-camera is a feasible, not time-consuming, noninvasive procedure in intraoperative sentinel node localization, offering extra confidence to the surgeon. In our hands, it was a very useful auxiliary imaging tool especially in the identification of nodes located deep in the axilla, which are difficult to detect at the preoperative lymphoscintigraphy. Additional multicenter studies involving a greater number of patients are necessary to confirm these promising data.

OBJECTIVE The objective of this study was to compare 2 diuretic renography procedures: F-15 versus F+10(sp) for diagnosis of obstructive uropathy in adults. METHODS Thirty-six patients with unilateral or bilateral hydronephrosis had 2 consecutive Tc-MAG3 diuretic renograms within 7 days, using the widely used procedure F-15 in supine position, and a new seated-position procedure whereby the patient drinks 400 to 500 mL of water at 5 minutes and receives an injection of 20 mg of furosemide at 10 minutes [F+10 (sp)]. RESULTS F-15 showed nonobstructive results in 63.9% of kidneys, obstruction in 26.4%, and equivocal findings in 6.9% and was not applicable in 2.8%. F+10(sp) showed nonobstructive results in 70.9%, obstruction in 27.8%, and equivocal result in 1.4% of kidneys. Nephroptosis was observed by F+10(sp) in 22.2% of kidneys. Adverse effects reported for the F-15 were hypotension in 2 patients, renal colic in 3 patients, and interruption due to voiding in 5 patients. No adverse effects were reported for F+10(sp). CONCLUSIONS This study shows that the F+10(sp) procedure reduces the equivocal findings of F-15 procedure in 36 patients. It can improve the accuracy and compliance, avoiding adverse effects and reducing bladder filling-related problems.

AIM: The purpose of this preliminary study was to evaluate the usefulness of 11C-choline PET/CT in patients with recurrent prostate cancer and hormone-sensitive disease treated with intermittent antiandrogen therapy scheme. PATIENTS AND METHODS: We retrospectively evaluated 10 patients after radical prostatectomy (n = 8) or external beam radiotherapy (n = 2) as primary therapy, studied with sequential 11C-choline PET/CT. The first PET/CT (PET1) was performed during antiandrogen therapy (ADT) and the second PET/CT (PET2) was performed after therapy interruption. Only patients with negative results at PET1 were included in the study. At the time of PET1, all patients were under ADT from at least 6 months (mean PSA 0.54 ng/mL). At the time of PET2, all patients had completed ADT for a mean period of 7 months. 11C-Choline PET/CT findings were validated by a follow-up of at least 12 months or histological confirmation in case of local relapse. RESULTS: PET2 has been able to detect the site of recurrences in all cases. At the time of PET2, mean PSA was 3.88 ng/mL; mean PSAdt was 2.46 months; and mean PSAvel was 6.94 ng/mL/year. Four out of 10 patients showed a single lesion, 5 out of 10 patients showed 2 lesions and 1 patient showed multiple lymph-node lesions. CONCLUSION: When performed during ADT interruption, 11C-choline PET/CT has been able to detect the site of recurrence in patients with increasing PSA values. In this context, 11C-choline PET/CT may help to assess the burden of disease or to change the therapeutic approach using more aggressive and addressed therapies like guided RT or salvage lymph-node dissection.

BACKGROUND AND AIM Papillary thyroid carcinomas smaller than 1 cm are classified as papillary microcarcinomas (PMCs). Papillary microcarcinomas are usually considered low-risk tumors; however in some cases, PMCs behave aggressively and metastasize early, giving rise to clinically metastatic disease. Debate exists in the literature about prognostic factors and therapeutic management to PMC. We report here the long-term experience of our referral center for malignant thyroid disease. METHODS We retrospectively analyzed 149 consecutive patients with PMC who underwent surgery at our institution between 2000 and 2005; 49 of them (33% of cases) were treated also with radioiodine therapy. Clinical and histopathological parameters potentially predicting patient outcome and recurrent disease were statistically investigated, after a minimum follow-up of 5 years. RESULTS After a median follow-up of 5.4 years (range, 5-11 years), 28 (19%) of 149 patients experienced recurrent disease. All of them were reoperated on and newly treated with radioiodine administration. Of these 28 patients, 27 are living without disease, whereas 1 patient died due to metastatic thyroid cancer to lungs. The multivariate statistical analysis identified extrathyroid invasion (odds ratio [OR], 58.54; P=0.013), the solid pattern (OR, 25.77; P

The aim of this study was to evaluate the efficacy of ¹⁸F-choline PET/CT (18FCH-PET/CT) in restaging patients previously treated by radical prostatectomy for a prostate cancer, presenting with biochemical relapse during follow-up (FU).Three hundred thirty-one patients referred to us from January 2009 to April 2011 to perform 18FCH PET/CT were evaluated: 233 of them (mean age 69.7 years) met the inclusion criteria of the study: (1) biochemical relapse after radical prostatectomy (trigger PSA0.2 ng/mL) (n=224) and (2) high risk for relapse (elevated Gleason score≥8) in spite PSA0.1 ng/mL during FU (n=9). Trigger PSA was available for all patients (mean 8 ng/mL) and in 44 of them also PSA kinetic (PSA velocity-PSAvel; PSA doubling time-PSAdt). Correlation between 18FCH PET/CT detection rate and trigger PSA, PSAvel, PSAdt, and tumoral spread distribution were evaluated by univariate and multivariate analysis. Subsequent minimum FU was 1 year (mean 26 months, range 12-40).Overall detection rate of 18FCH PET/CT was 54%, which significantly increased when the trigger PSA increases (P0.001). PET-positive patients presented a "fast" PSA kinetic (mean PSAdt=6 months and mean PSAvel=9.3 ng/mL/yr), while PET-negative patients presented a "slow" PSA kinetic (mean PSAdt=15.4 months and mean PSAvel=0.9 ng/mL/yr). Disease relapse was local in 17% of cases, distant in 66%, and combined in 17%.Overall 18FCH PET/CT detection rate was 54% (ie, similar to that reported in literature with ¹¹C-choline), which increases with the increase in trigger PSA: this condition was particularly true in patients with accelerated PSA kinetic. In about 20% of patients, 18FCH PET/CT demonstrated local relapses early enough to offer locoregional radiation therapy.

It is well known the useful role of ¹⁸F-FDG-PET/CT for differential diagnosis between benign and malignant disease, for staging, for monitoring response and for prognosis regarding mesothelioma. Recently, literature was enriched with new interesting studies regarding the potential applications of ¹⁸F-FDG-PET/CT in this field. The purpose of this review is to evaluate articles published on line (PubMed) from January 2011 until October 2012 in order to obtain an overview of recent progress of molecular imaging in malignant mesothelioma. The main topics concern the use of ¹⁸F-FDG-PET/CT in radiation therapy planning, monitoring of treatment (surgery/chemotherapy) response and prognosis assessment.

Last generation PET tomographs are equipped with a state-of-the-art CT scanner. Normally, CT images are acquired with suboptimal parameters and without intravenous contrast media, being used for attenuation correction and localization only. For this reason, no CT report is usually provided. Most of the patients who are referred for an FDG PET/CT scan, however, present with a diagnostic CT indicating that a PET/CT is required to characterize otherwise equivocal findings and, in the end, undergo both the techniques to reach a final diagnosis. The aim of this study was to evaluate the impact of the contemporary execution of both the techniques employing a PET/CT scanner on the conclusiveness of the final report. Secondary aim was to verify the concordance of the two reports. PATIENTS AND METHODS: Thirty-eight patients affected by hypermetabolic malignant diseases (15F-23M, mean age 58±17 years) were enrolled. Twenty-two were in staging, 16 in restaging. They underwent a standard FDG PET/CT scan immediately followed by a diagnostic contrast enhanced (ce)CT scan acquired on the same tomograph. The PET/CT scan was reported by a nuclear medicine physician while the ceCT by a radiologist, independently. Then, they wrote a conclusive paragraph formulated by consensus. The results were compared in terms of stage (FDG PET/CT vs. ceCT and vs. final stage by consensus) and positivity of T, N and M by the inter-rater agreement K. RESULTS: In all the patients, a final, conclusive and agreed stage was reached. There was a high concordance in terms of stage between FDG PET/CT and ceCT (K=0.874), ceCT and final stage (K=0.936), FDG PET/CT and final stage (K=0.938). In two cases, ceCT contributed significantly to the final stage, while PET/CT in four patients. More in details, for the detection of T, there was a complete concordance between PET/CT and ceCT, despite PET/CT wasn't able to provide an accurate evaluation of nearby structures infiltration. K was 0.785 for the assessing of N and 0.718 for M. In general, ceCT was more sensitive for the detection of lung and brain metastasis. FDG PET/CT was more accurate for the identification of nodal metastasis and small distant lesions, especially in the abdomen. DISCUSSION: Our data show that the execution of PET/ceCT in the same session by using the same hybrid tomography increases the quality of the final report by nuclear physician and radiologist and provides clear diagnostic information to the clinician. Copyright © 2012 Elsevier Masson SAS. All rights reserved. PMID: 23433901 [PubMed - indexed for MEDLINE]

Although tumors of the parapharyngeal space are rare, they represent a formidable diagnostic and treatment challenge. The differentiation of a retrostyloid lesion from a prestyloid lesion is critical for guiding the differential diagnosis. The majority of lesions involving the retrostyloid parapharyngeal space are either peripheral nerve sheath tumors, head & neck paragangliomas or metastatic lymph node metastases. This article provides insights into the many currently available radiological and radionuclide imaging procedures and guides clinicians toward their appropriate use. In the near future, many patients might also benefit from new diagnostic approaches such as high resolution integrated PET/MRI and new tracers that enable "in vivo" assessment of these tumors at molecular level.

Purpose Every PET scanner suffers of the partial volume effect (PVE), that is a loss of contrast in small lesions causing a worsening in standardized uptake value (SUV) accuracy, that is critical if quantitative PET/CT imaging is used for diagnosis and therapy. Methods In order to quantify PVE and optimize our clinical protocols to minimize this effect in a last generation PET/CT scanner, we utilized a cylindrical phantom equipped with ten mini- and micro-volume hollow spheres. The lesion detectability and the SUV accuracy were evaluated at a fixed spheres to background intrinsic contrast (activity concentration ratio 8:1) but in different scan conditions: (a) acquisition modality (3D vs. 2D), (b) number of subset per iteration, (c) type of post-reconstruction filter and (d) activity concentration (i.e. total counts). Also the effect of different absorber thickness was evaluated. Results Small lesion detectability resulted better in images acquired in 3D mode rather than 2D, mainly because of the lower noise produced by the fully-3D algorithm. The number of reconstruction iterations and the post-processing filter used affected both the contrast underestimation and the spatial resolution. Decreasing the 18F activity injected according to the low-dose protocol, the small lesions could be distinguished from the background down to a diameter of 6.2 mm and the SUV accuracy did not deteriorate. Adding absorber thickness around the phantom, the image noise slightly increased while SUV accuracy did not change. Conclusions The hybrid PET/CT scanner we evaluated showed good performances, mainly in 3D acquisition modality. The phantom measurements showed that the most appropriate reconstruction protocol derived from a compromise between the contrast accuracy and the noise variance in PET images. The low-dose protocol clinically used demonstrated no loss in SUV accuracy and an adequate lesion detectability for lesions down to 6.2 mm in diameter.

L-6-fluoro 3,4-dihydroxyphenylalanine (18F-DOPA), an amino acid-based radiopharmaceutical, is increasingly being used in the detection and management of neuroendocrine tumours. Knowledge of the normal biodistribution of this radiopharmaceutical is essential for the proper interpretation of such studies, but the literature available is scanty due to the rarity of these tumours. The aim of this study is to evaluate the biodistribution pattern and normal variants of 18F-DOPA in a cohort of patients with neuroendocrine tumours using semiquantitative analysis (maximum standardized uptake value).We analysed 107 consecutive 18F-DOPA PET/CT studies of patients referred with medullary carcinoma of the thyroid (43), phaeochromocytoma including cases of Von Hippel Lindau syndrome and multiple endocrine neoplasia type IIA cases (34), paraganglioma (14) and other neuroendocrine tumours (16). The study population were divided into two groups: those with negative 18F-DOPA PET/CT scans (32) and those with positive scans (75). The biodistribution of 18F-DOPA in each group was measured and compared between the two groups.The physiological biodistribution in the basal ganglia and liver parenchyma showed no variability between the two groups. Conversely, uptake in the pancreas (particularly the uncinate process) and adrenals showed considerable variability between the groups. However, these differences were found not to be significant on statistical analysis.The data presented may provide useful information in understanding the physiologic biodistribution of DOPA and its variants, for the purpose of improving the interpretation of 18F-DOPA PET/CT.

A water-soluble meso-substituted porphyrin (H(2)TCP) bearing 36 boron atoms, which appeared to be an efficient photodynamic sensitiser (singlet oxygen quantum yield=0.44), was studied for its accumulation by murine melanotic melanoma cells (B16F1). The amount of H(2)TCP in the cells increased with the porphyrin dose in the incubation medium up to, and at least, 100 microM concentrations with no significant cytotoxic effect in the dark. Moreover, the H(2)TCP uptake increased with the incubation time reaching a plateau value corresponding with the recovery of 0.4 nmol of H(2)TCP per mg of cell proteins after 24h incubation. Fluorescence microscopy observations showed that the porphyrin was largely localized intracellularly, exhibiting a discrete distribution in the cytoplasm with a pattern which was closely similar to that observed for the endosomal probe Lucifer yellow. The photosensitising efficiency of the H(2)TCP toward B16F1 cells was studied for different irradiation (1-15 min) and incubation (1-24 h) times. Nearly complete (95%) cell mortality was obtained upon incubation with 20 microM H(2)TCP and 10 min irradiation with red light (600-700 nm, 20 mW/cm(2)). The porphyrin was also accumulated in appreciable amounts by the tumour tissue after intravenous injection to C57BL/6 mice bearing a subcutaneously transplanted melanotic melanoma. Maximum accumulation in the tumour was achieved by administration of H(2)TCP dissolved in the ternary mixture 20% dimethylsulfoxide (DMSO)-30% polyethyleneglycol (PEG 400)-50% water. Thus, this porphyrin could act as both a photodynamic therapy agent and a radiosensitising agent for boron neutron capture therapy.