Significant dose reduction is feasible in FDG PET/CT protocols without compromising diagnostic quality

Purpose: To reduce the radiation dose to patients by optimizing oncological FDG PET/CT protocols. Methods: The baseline PET/CT protocol in our institution for oncological PET/CT examinations consisted of the administration of 5.18 MBq/kg of FDG and a CT acquisition with a reference current-time product of 120 mAs. In 2016, FDG activity was reduced to 4.44 and 3.70 MBq/kg and reference CT current-time-product was reduced to 100 and 80 mAs. 322 patients scanned with different protocols were retrospectively evaluated. For each patient, effective dose was calculated. The overall image quality was subjectively rated by the referring physician on a 4-point scale (IQ score: 1 excellent, 2 good, 3 poor but interpretable, 4 poor not interpretable). Image quality was quantitatively evaluated measuring noise in the liver. Results: CT Results: Effective dose was progressively reduced from 9.5 ± 2.8 to 8.0 ± 2.3 and 6.2 ± 1.5 mSv (p 2) did not increase. PET Results: Effective dose was gradually reduced from 6.5 ± 1.4 to 5.7 ± 1.3 and 5.0 ± 1.0 mSv (p < 0.001). Average dose reduction was 23.4%. IQ score (p < 0.05) and noise (p < 0.001) significantly degraded for lower activity protocols. However, all images with reduced activity were scored as interpretable (IQ score ≤ 3). Conclusions: A significant radiation dose reduction of 28.7% was reached. Despite a slight reduction in image quality, the new regime was successfully implemented with readers reporting unchanged clinical confidence

Assessment of indeterminate pulmonary nodules detected in lung cancer screening: Diagnostic accuracy of FDG PET/CT

Background: A major drawback of lung cancer screening programs is the high frequency of false-positive findings on computed tomography (CT). We investigated the accuracy of selective 2-[fluorine-18]- fluoro-2-deoxy-d-glucose (FDG) Positron Emission Tomography/Computed Tomography (PET/CT) scan in assessing radiologically indeterminate lung nodules detected in lung cancer screening. Methods: FDG PET/CT was performed to characterize 64 baseline lung nodules >10 mm and 36 incidence nodules detected on low-dose CT screening in asymptomatic current or former smokers (83 men, age range 40–83 years) at high risk for lung cancer. CT images were acquired without intravenous contrast. Nodules were analyzed by size, density, and metabolic activity and visual scored on a 5-point scale for FDG uptake. Nodules were classified as negative for malignancy when no FDG uptake was observed, or positive when focal uptake was observed in the visual analysis, and the maximum standardized uptake value (SUVmax) was measured. Final diagnosis was based on histopathological evaluation or at least 24 months of follow-up. Results: A total of 100 nodules were included. The prevalence of lung cancer was 1%. The sensitivity, specificity, NPV and PPV of visual analysis to detect malignancy were 84%, 95%, 91%, and 91%, respectively, with an accuracy of 91% (AUC 0.893). FDG PET/CT accurately detected 31 malignant tumors (diameters 9–42 mm, SUVmax range 0.6–14.2) and was falsely negative in 6 patients. With SUVmax thresholds for malignancy of 1.5, 2, and 2.5, specificity was 97% but sensitivity decreased to 65%, 49%, and 46% respectively, and accuracy decreased to 85%, 79%, and 78% respectively (AUC 0.872). Conclusions: The visual analysis of FDG PET/CT scan is highly accurate in characterizing indeterminate pulmonary nodules detected in lung cancer screening with low-dose CT. Semi-quantitative analysis does not improve the accuracy of FDG PET/CT over that obtained with a qualitative method for lung nodule characterization

Impact of sex, age, and risk factors for venous thromboembolism on the initial presentation of first isolated symptomatic acute deep vein thrombosis

Thrombosis and Hemostasi

CMS physics technical design report: Addendum on high density QCD with heavy ions

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies ,will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction - Quantum Chromodynamics (QCD) - in extreme conditions of temperature, density and parton momentum fraction (low-x). This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield "tomographic" information of the hottest and densest phases of the reaction.0info:eu-repo/semantics/publishe