Positron emission tomography (PET) is a nuclear imaging technology (also referred to as molecular imaging) that enables visualization of metabolic processes in the body. The basics of PET imaging is that the technique detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (also called radiopharmaceuticals, radionuclides or radiotracer). The tracer is injected into a vein on a biologically active molecule, usually a sugar that is used for cellular energy. PET systems have sensitive detector panels to capture gamma ray emissions from inside the body and use software to plot to triangulate the source of the emissions, creating 3-D computed tomography images of the tracer concentrations within the body.
In scans of a 62-yr-old man with Gleason 4+3 PCa treated with radical prostatectomy, with rising PSA level (1.32) and PSA doubling time of 3.7 months, 64CuCl2-PET/CT images revealed 2 positive small left iliac lymph nodes (A,C), whereas 18F-Choline PET/CT (B,D) was negative (arrows). Image courtesy of A Piccardo et al., Galliera Hospital, Genoa, Italy.
68Ga-PSMA PET/CT images showing multifocal PCA in peripheral zone with GS of 5 1 5 5 10. (A and C) Axial PET images. (B and D) Fused PET/CT images. SUVmax of lesion in B was 84.3 and that of lesion in D was 5.7. IRS was 3, and 80% of cells were stained. Credit: Senior author V Prasad, Charité Universitätsmedizin Berlin, Berlin, Germany.
Representative PET/CT images of 18F-FDS and 18F-FDG in inflamed mice. Mice were inoculated with dead K. pneumoniae (10^8 CFU/mL). Imaging was performed for days 1, 2, 3 and 4 using 18F-FDG and 18F-FDS. CT images showed clear inflammation on day 2 and day 3 with corresponding high 18F-FDG uptake on PET. No significant uptake of 18F-FDS was detected for any of those 4 days. Credit: J Li et al., University of Louisville School of Medicine, Louisville, Ky.
Longitudinal PET imaging with 18F-AV45. PET imaging shows the average 18F-AV45 uptake per animal group at 8 and 13 months of age. A significant interaction of genotype treatment was observed in the cortex (p = 0.0248), hippocampus (p = 0.0071) and thalamus (p = 0.0084), indicating reduced [18F]-AV45 uptake in BACE1 inhibited transgenic mice. Credit: MICA, University of Antwerp, Belgium.
Transaxial 11Csarcosine hybrid PET/CT showed a (triangulated) adenocarcinoma in the transition zone of the anterior right prostate gland on PET (A), CT (B), and a separately obtained T2?weighted MR sequence (C) with resulting PET/MRI registration (D). Image courtesy of M. Piert et al., University of Michigan, Ann Arbor, Mich.
Example of a patient with an upper left lung NSCLC: A: FDG; B: FDG PET/CT; C: Planning radiotherapy based on FDG (66Gy) with BTVm (GTV), CTV and PTV; D: PET FMISO E: FMISO PET/CT; F: boost based on the FMISO PET (76Gy) with BTVh (biological hypoxic target volume) and PTV boost. Credit: QuantIF – LITIS EA 4108 – FR CNRS 3638, Henri Becquerel Cancer Center, Rouen, France