Dosimetric methodology for 131I therapy for benign thyroid diseases

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Evaluation of radiographic texture analysis for the characterization of 3D bone micro-architecture: influence of spatial resolution

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Assessment of the Stratos, a New Pencil-Beam Bone Densitometer: Dosimetry, Precision, and Cross Calibration

The goal of this study was to assess a new pencil-beam densitometer, the Stratos (Diagnostic Medical Systems, Pérols, France). Evaluation of the dosimetry and precision were done together with an in vivo cross-calibration study performed with the fan beam densitometer Discovery A (Hologic, Bedford, MA). The results indicated that the Stratos performed bone mineral density (BMD) measurements with a good precision, low radiation dose, and good agreement with the Discovery A. The air dose, measured by an ionization chamber, was 40\textgreekmGy. The effective dose was assessed using an anthropomorphic phantom and thermoluminescent detectors resulting in 1.96 and 0.31\textgreekmSv for a lumbar spine and proximal femur scan, respectively. The average scattered dose rate at a distance of 1m from the device was 1.06 and 1.21\textgreekmSv.h -1 in the lumbar spine and left proximal femur scan mode, respectively. For the precision evaluation, 30 patients underwent 2 lumbar spine and 2 proximal femur scans with repositioning after each scan. The percentage root-mean-square coefficient of variation was 1.22%, 1.38%, 2.11%, and 0.86% for the lumbar spine (L1-L4), lumbar spine (L2-L4), femoral neck, and total hip, respectively. The cross-calibration studies were done on 57 patients (60±9yr). Lumbar spine, left neck, and left total hip mean BMD were 3.10% lower and 11.94% and 8.83% higher, respectively, with the Stratos compared with the Discovery A. Cross-calibration equations were calculated with a correlation coefficient of 98% (p\textless0.01) for the lumbar spine (L2-L4), 94% (p\textless0.01) for the left neck, and 92% (p\textless0.01) for the left total hip. After standardizing the Stratos measures using the cross-calibration equations, LIN's concordance correlation coefficient was 0.98, 0.93, and 0.92 for the lumbar spine (L2-L4), left neck, and total hip, respectively. © 2011 The International Society for Clinical Densitometry

Place of 18F-FDG-PET with computed tomography in the diagnostic algorithm of patients with fever of unknown origin

International audienceThere is evidence for the interest of 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG-PET/CT) in fever of unknown origin (FUO) clinical investigation. However, little and conflicting data exist about its place in the investigation procedure. The aim of this work was to evaluate the clinical value of 18FFDG- PET/CT in patients with FUO and identify patients who need early 18F-FDG-PET/CT rather than a last-resort procedure. We performed a 2-year retrospective cohort study at the Nîmes University Hospital, France. A total of 79 patients (36 men, 43 women, mean age 54.0 ± 16.2 years) with FUO underwent 18F-FDG-PET/CT. A final diagnosis was established in 61 (77.2 %) cases. Aetiologies of FUO were determined using 18F-FDG-PET/CT findings in 45 (73.8 % of patients with diagnosis) cases. The sensibility and specificity value were 98 % and 87 %, respectively. The presence of adenopathy, low haemoglobin and increased Creactive protein (CRP) were predictors of high-yield 18FFDG- PET/CT. 18F-FDG-PET/CT may help to detect most causes of FUO. The predictors of high-yield 18F-FDG-PET/ CT found in this study can help identify patients likely to benefit from specific and early imaging techniques. © Springer-Verlag 2011

Relevance of 2D radiographic texture analysis for the assessment of 3D bone micro-architecture

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Les patients avec une de ́couverte fortuite d’une hyperfixation myocardique focale de 18FDG devraient-ils be ́ne ́ficier d’une scintigraphie myocardique de perfusion?

International audiencePurpose. – Focal F-18-fluoro-deoxy-glucose uptake in the myocardium can be a sign of resting myocardial ischemia. The purpose of our study was to assess the relevance of performing myocardial perfusion scintigraphy to screen for myocardial ischemia in patients with an incidental finding of focal myocardial F-18-fluoro-deoxy-glucose uptake on a routine F-18-fluoro-deoxy-glucose positron- emission-tomography-computed-tomography.Methods. – In our retrospective multicentric study, patients were included if they had had an incidental finding of myocardial focal F-18-fluoro-deoxy-glucose uptake on a routine F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography and had also undergone myocardial perfusion scintigraphy within 3 months before or after the F-18-fluoro-deoxy-glucose positron-emission- tomography-computed-tomography. Patients with a pattern of ischemia or scar on the myocardial perfusion scintigraphy in the same territory as the focal F-18-fluoro-deoxy-glucose uptake were considered positive.Results. – Seven of the 34 included patients were positive, with an abnormality on the MPS data in the same territory as the focal myocardial F-18-fluoro-deoxy-glucose uptake. 2 of the 6 patients with focal F- 18-fluoro-deoxy-glucose uptake in the left anterior descending vascular supply territory and 2 of the 4 patients with focal F-18-fluoro-deoxy-glucose uptake in the standard right coronary artery territory had an abnormal myocardial perfusion scintigraphy. All 12 patients with focal F-18-fluoro-deoxy- glucose uptake restricted to the basal anterolateral and basal inferolateral segments were negative. Conclusion. – PatientswithanincidentalfindingoffocalF-18-fluoro-deoxy-glucoseuptakeonaroutine F-18-fluoro-deoxy-glucose positron-emission-tomography-computed-tomography may be considered as being at risk for coronary artery disease, when this uptake is multisegmentary in the same typical coronary territory and not restricted to the basal anterolateral and basal inferolateral segments

What are the most relevant 2D radiographic texture parameters to assess 3D bone micro-architecture ?

International audienc

A procedure for the evaluation of 2D radiographic texture analysis to assess 3D bone micro-architecture

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