How to obtain the image-derived blood concentration from Zr-immuno-PET scans.

Background: PET scans using zirconium-89 labelled monoclonal antibodies (Zr-mAbs), known as Zr-immuno-PET, are made to measure uptake in tumour and organ tissue. Uptake is related to the supply of Zr-mAbs in the blood. Measuring activity concentrations in blood, however, requires invasive blood sampling.

Validation of simplified uptake measures against dynamic Patlak K for quantification of lesional Zr-Immuno-PET antibody uptake.

Purpose: Positron emission tomography imaging of zirconium-89-labelled monoclonal antibodies (Zr-Immuno-PET) allows for visualisation and quantification of antibody uptake in tumours in vivo. Patlak linearization provides distribution volume (V) and nett influx rate (K) values, representing reversible and irreversible uptake, respectively. Standardised uptake value (SUV) and tumour-to-plasma/tumour-to-blood ratio (TPR/TBR) are often used, but their validity depends on the comparability of plasma kinetics and clearances.

Noninvasive Quantification of Myocardial 11C-Meta-Hydroxyephedrine Kinetics.

Unlabelled: (11)C-meta-hydroxyephedrine ((11)C-HED) kinetics in the myocardium can be quantified using a single-tissue-compartment model together with a metabolite-corrected arterial blood sampler input function (BSIF). The need for arterial blood sampling, however, limits clinical applicability. The purpose of this study was to investigate the feasibility of replacing arterial sampling with imaging-derived input function (IDIF) and venous blood samples.

Calibration of PET/CT scanners for multicenter studies on differentiated thyroid cancer with (124)I.

Background: Studies on imaging of differentiated thyroid cancer (DTC) using (124)I often require a multicenter approach, as the prevalence of DTC is low. Calibration of participating scanners is required to obtain comparable quantification. As determination of a well-defined range of recovery coefficients is complicated for various reasons, a simpler approach based on the assumption that the iodine uptake is highly focal with a background that significantly lacks radioactivity might be more efficient.

Multicenter harmonization of 89Zr PET/CT performance.

Unlabelled: This study investigated the feasibility of quantitative accuracy and harmonized image quality in (89)Zr-PET/CT multicenter studies.

Methods: Five PET/CT scanners from 3 vendors were included. (89)Zr activity was measured in a central dose calibrator before delivery.

Toward prediction of efficacy of chemotherapy: a proof of concept study in lung cancer patients using [¹¹C]docetaxel and positron emission tomography.

Purpose: Pharmacokinetics of docetaxel can be measured in vivo using positron emission tomography (PET) and a microdose of radiolabeled docetaxel ([(11)C]docetaxel). The objective of this study was to investigate whether a [(11)C]docetaxel PET microdosing study could predict tumor uptake of therapeutic doses of docetaxel.

Experimental Design: Docetaxel-naïve lung cancer patients underwent 2 [(11)C]docetaxel PET scans; one after bolus injection of [(11)C]docetaxel and another during combined infusion of [(11)C]docetaxel and a therapeutic dose of docetaxel (75 mg·m(-2)).

Cerebral blood flow and glucose metabolism in healthy volunteers measured using a high-resolution PET scanner.

Background: Positron emission tomography (PET) allows for the measurement of cerebral blood flow (CBF; based on [15O]H2O) and cerebral metabolic rate of glucose utilization (CMRglu; based on [18 F]-2-fluoro-2-deoxy-d-glucose ([18 F]FDG)). By using kinetic modeling, quantitative CBF and CMRglu values can be obtained. However, hardware limitations led to the development of semiquantitive calculation schemes which are still widely used.

Rapid decrease in delivery of chemotherapy to tumors after anti-VEGF therapy: implications for scheduling of anti-angiogenic drugs.

Current strategies combining anti-angiogenic drugs with chemotherapy provide clinical benefit in cancer patients. It is assumed that anti-angiogenic drugs, such as bevacizumab, transiently normalize abnormal tumor vasculature and contribute to improved delivery of subsequent chemotherapy. To investigate this concept, a study was performed in non-small cell lung cancer (NSCLC) patients using positron emission tomography (PET) and radiolabeled docetaxel ([(11)C]docetaxel).

Absolute quantification of [(11)C]docetaxel kinetics in lung cancer patients using positron emission tomography.

Purpose: Tumor resistance to docetaxel may be associated with reduced drug concentrations in tumor tissue. Positron emission tomography (PET) allows for quantification of radiolabeled docetaxel ([(11)C]docetaxel) kinetics and might be useful for predicting response to therapy. The primary objective was to evaluate the feasibility of quantitative [(11)C]docetaxel PET scans in lung cancer patients.

Optimizing an online SPE-HPLC method for analysis of (R)-[11C]1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide [(R)-[11C]PK11195] and its metabolites in humans.

(R)-[11C]PK11195 is used as a positron emission tomography tracer for activated microglia in several neurological disorders. Quantification of specific binding requires a metabolite-corrected plasma input function. In this study, a high-performance liquid chromatography (HPLC) procedure with online solid phase extraction was modified for analyzing (R)-[11C]PK11195 plasma samples, yielding total sample recoveries of more than 98%.

Validation of a multiwell gamma-counter for measuring high-pressure liquid chromatography metabolite profiles.

Objectives: The purpose of this study was to verify the accuracy and reproducibility of a multiwell counter to assess its suitability for use within human PET studies in which metabolizing (11)C tracers are used. Such tracers often require metabolite analysis for deriving plasma metabolite-corrected input curves. High-pressure liquid chromatography (HPLC) with on-line activity measurement is often unreliable for later plasma samples due to the poor sensitivity of the on-line activity detector.

Measurement of 18F-FDG concentrations in blood samples: comparison of direct calibration and standard solution methods.

Objective: The purpose of this study was to compare the accuracy and reliability of 2 well counter methods for measuring the activity concentration of (18)F-FDG in blood samples.

Methods: Three to 5 blood samples from 154 patient studies were weighed and measured in a well counter. The (18)F-FDG activity concentration was derived using, first, a direct calibration factor to convert measured well counter readings into activity concentration and, second, a comparison of measured counts with those of a specified standard solution.