Quantification of the metabolic rate of glucose from Dynamic Whole-Body PET examinations requires measurements of the time course of the radioactivity concentrations in arterial blood by blood sampling, and in the tissue of interest by dynamic PET. Invasive arterial blood sampling cannot be part of a standard examination, and therefore the blood samples need to be replaced by activity concentrations derived from the PET images, usually from small volumes in the descending aorta or left ventricle.

Newly developed scanner software (Siemens) allows automated CT-based identification of blood pool regions and extraction of an image-derived blood input function from the corresponding PET data.

However, this automated method needs validation, as it could be prone to systematic errors caused by limited spatial resolution, patient movement, and image reconstruction. We will use invasively measured arterial blood samples as a reference for validation of methods to extract non-invasive PET image-derived input functions and quantify any systematic errors that could propagate to the resulting parametric images.

Inclusion Criteria:

• Patients with a planned clinical standard PET/CT as part of pre-therapeutic staging, response assessment scanning.
• Good performance status, which will allow us to obtain informed consent to draw the required arterial blood samples during the examination, and which will permit patients to lay still in the scanner for at least 70 min.

Exclusion Criteria:

• • Age < 18 or > 85 years

  • Patients that can not tolerate a PET scan (f.ex: claustrophobia).