Approaches to improving the detection sensitivity of optical modulation based radiation detection method for positron emission tomography

Abstract. Clay plays a prominent role as barrier material in the geosphere. The small particle sizes cause extremely small pore sizes and induce low permeability and high sorption capacity. Transport of dissolved species by molecular diffusion, driven only by a concentration gradient, is less sensitive to the pore size. Heterogeneous structures on the centimetre scale could cause heterogeneous effects, like preferential transport zones, which are difficult to assess. Laboratory measurements with diffusion cells yield limited information on heterogeneity, and pore space imaging methods have to consider scale effects. We established positron emission tomography (PET), applying a high-resolution PET scanner as a spatially resolved quantitative method for direct laboratory observation of the molecular diffusion process of a PET tracer on the prominent scale of 1–100 mm. Although PET is rather insensitive to bulk effects, quantification required significant improvements of the image reconstruction procedure with respect to Compton scatter and attenuation. The experiments were conducted with 22Na and 124I over periods of 100 and 25 days, respectively. From the images we derived trustable anisotropic diffusion coefficients and, in addition, we identified indications of preferential transport zones. We thus demonstrated the unique potential of the PET imaging modality for geoscientific process monitoring under conditions where other methods fail, taking advantage of the extremely high detection sensitivity that is typical of radiotracer applications.

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Quantitative experimental monitoring of molecular diffusion in clay with positron emission tomography

10.5194/se-2016-34 ◽

2016 ◽

Cited By ~ 1

Author(s):

Johannes Kulenkampff ◽

Abdelhamid Zakhnini ◽

Marion Gründig ◽

Johanna Lippmann-Pipke

Keyword(s):

Positron Emission Tomography ◽

Molecular Diffusion ◽

Scale Effects ◽

Imaging Modality ◽

Detection Sensitivity ◽

Emission Tomography ◽

Pet Tracer ◽

Positron Emission ◽

Small Pore ◽

Preferential Transport

Abstract. Clay plays a prominent role as barrier material in the geosphere. The small particle sizes cause extremely small pore sizes and induce low permeability and high sorption capacity. Transport of dissolved species by molecular diffusion is less sensitive to the pore size. Heterogeneous structures on centimetre scale could cause heterogeneous effects, like preferential transport zones, which are difficult to assess. Laboratory measurements with diffusion cells yield limited information on heterogeneity, and pore space imaging methods have to consider scale effects. We established positron emission tomography (PET); applying a high-resolution PET-scanner, as spatially resolved quantitative method for direct laboratory observation of the diffusion process of a PET-tracer on the prominent scale of 1–100 mm. Although PET is rather insensitive to bulk effects, quantification required significant improvements of the image reconstruction procedure with respect to Compton scatter and attenuation. The experiments were conducted with 22Na and 124I over periods of 100, respectively 25 days. From the images we derived trustable anisotropic diffusion coefficients and, in addition, we identified indications for preferential transport zones. We thus demonstrated the unique potential of the PET imaging modality for geoscientific process monitoring under conditions where other methods fail, taking advantage of the extremely high detection sensitivity that is specific to radiotracer applications.

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A new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

10.1117/12.2241608 ◽

2016 ◽

Author(s):

Li Tao ◽

Henry M. Daghighian ◽

Craig S. Levin

Keyword(s):

Positron Emission Tomography ◽

Optical Properties ◽

Ionizing Radiation ◽

Radiation Detection ◽

Emission Tomography ◽

Positron Emission

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Diagnostic Value of Delayed PET/MR in Liver Metastasis in Comparison With PET/CT

Frontiers in Oncology ◽

10.3389/fonc.2021.717687 ◽

2021 ◽

Vol 11 ◽

Author(s):

Nina Zhou ◽

Xiangxi Meng ◽

Yan Zhang ◽

Boqi Yu ◽

Jianmin Yuan ◽

...

Keyword(s):

Positron Emission Tomography ◽

Liver Metastasis ◽

Predictive Value ◽

Diagnostic Value ◽

Lesion Detection ◽

Detection Sensitivity ◽

Emission Tomography ◽

Liver Lesions ◽

Positron Emission ◽

Pet Ct

ObjectivesThe aim of this study was to evaluate the value of a delayed positron emission tomography/magnetic resonance (PET/MR) scan relative to a single positron emission tomography/computed tomography (PET/CT) scan for liver metastasis detection.MethodsIn this study, 70 patients with solid malignancies and suspicious liver lesions undergoing 2-deoxy-2-[18F]fluoro-D-glucose [(18F)FDG] PET/CT and subsequent delayed liver PET/MR scans were analyzed. The histopathological analysis and/or imaging follow-up were performed as the standard of reference. Lesion maximum standardized uptake value (SUVmax), diameter, and tumor to nontumor ratio (T/N) were measured. Lesion detection sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both examinations.Results(1) The standard of reference revealed 208 liver lesions in 70 patients (metastasis in 56 patients with 196 lesions; benign in 14 patients with 12 lesions). Compared with PET/CT, PET/MR had higher accuracy (98.6% vs. 78.6%), sensitivity (98.2% vs. 76.8%), and specificity (100.0% vs. 85.7%) (2). The therapeutic strategies of 29 patients (41.4%) needed reconsideration after the additional PET/MR, including new metastases detected (13/70), new affected lobes identified (14/70), and false-positive corrected (2/70) (3). PET/MR detected significantly more metastases than PET/CT did, especially with small lesions. The SUVmax of the same lesion correlated well between the two acquisitions, while the delayed PET showed a higher T/N ratio.ConclusionsIn liver metastasis detection, the diagnostic value of the delayed PET/MR is validated to be superior to that of PET/CT, which may aid the clinical decision-making.

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