Positron Emission Tomography (PET) is a molecular imaging modality that visualizes metabolic activity, cellular function, and biochemical processes within the body. PET is essential in oncology, neurology, and cardiology, providing information that cannot be obtained with CT, MRI, or ultrasound.
PET is most commonly performed as PET/CT, combining metabolic imaging with anatomical detail for precise localization of disease.
PET imaging uses radiopharmaceuticals labeled with positron‑emitting isotopes. When positrons interact with electrons, they produce annihilation photons detected by the PET scanner. These signals are reconstructed into 3D images showing metabolic activity.
The most common PET tracer is F‑18 FDG, which highlights areas of increased glucose metabolism—often corresponding to tumors, inflammation, or infection.
Other tracers target amyloid plaques, myocardial perfusion, neuroreceptors, and prostate‑specific membrane antigen (PSMA).
Source: Society of Nuclear Medicine and Molecular Imaging
PET is the gold standard for cancer staging, treatment planning, and monitoring therapy response. It detects disease earlier than structural imaging and identifies active tumor tissue.
Neurologic PET evaluates dementia, epilepsy, and neurodegenerative disorders. Cardiac PET assesses myocardial viability and perfusion with exceptional accuracy.
PET/CT and PET/MRI hybrid systems combine functional and anatomical imaging for superior diagnostic precision.
Source: American College of Radiology
PET/CT
PET/MRI
Whole‑Body PET
F‑18 FDG
Ga‑68 PSMA
F‑18 Amyloid Tracers
Oncology Staging
Neurologic Imaging
Cardiac Viability
Source: SNMMI
PET facilities follow accreditation standards from the American College of Radiology (ACR) and the Intersocietal Accreditation Commission (IAC). These standards ensure proper radiopharmaceutical handling, scanner calibration, and technologist competency.
Quality control includes daily blank scans, normalization, energy window checks, and dose calibrator accuracy.
Source: ACR / IAC
Is PET safe? Yes. Radiation doses are moderate and tracers decay quickly.
How long does a PET scan take? Most exams take 1.5–2 hours including uptake time.
Why is PET combined with CT? CT provides anatomical detail to localize PET findings.
Source: SNMMI
PET technologists require training in radiopharmacy, PET physics, scanner operation, patient preparation, and radiation safety. Certification is available through ARRT and NMTCB.
Students learn to prepare tracers, manage uptake protocols, and interpret metabolic patterns.
Source: NMTCB