03 Nuclear
Standardized uptake value
SUV from activity concentration, injected dose, and body weight.
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Simulation
Standardized uptake value — Change the numbers; the scene follows.
Where it works
PET/CT
Patient / uptake
In the patient on the PET couch — activity concentration, SUV, and internal dose.
Open this machineFormula
Variables
Results
SUV
Standardized uptake value
2.8g/ml
Explanation
What it means
SUV is activity concentration in a voxel divided by injected activity per body mass. A uniform distribution would give SUV = 1 g/ml. Tumours, brain and myocardium run higher; lung and fat run lower. SUV_max is the usual PET reporting figure. This is a working relation in Nuclear medicine.
Where it is used
Clinically it sits on the PET/CT — Patient / uptake. In the patient on the PET couch — activity concentration, SUV, and internal dose. Nuclear-medicine relations sit in the hot lab, on the camera, and in the voxel: decay, SUV, TOF, and counting statistics. They decide whether an uptake is real or a clock error.
PET/CT · Open this machineHow to use it
C in kBq/ml (from the PET DICOM), A decay-corrected to scan start in MBq, m in kg. SUV_bw uses body weight; lean-body-mass and BSA variants exist. Change one input and watch the curve and the simulation follow.
Symbols
- CActivity concentration12 kBq/ml
- AInjected activity (decay-corrected)300 MBq
- mBody weight70 kg
Worked example
A typical case from the default values: C = 12 kBq/ml (Activity concentration); A = 300 MBq (Injected activity (decay-corrected)); m = 70 kg (Body weight). Substituting into the relation gives SUV = 2.8 g/ml. These are teaching numbers — align them with your machine.
Typical values give
- SUV = 2.8g/ml
Where it comes from
The displayed formula is the working relation. SUV from activity concentration, injected dose, and body weight. Usual reference: PET physics / Cherry. Derive it in the specialty lesson, then return here to pin the numbers.
Reference: PET physics / Cherry
Assumptions & limits
Assumes 1 ml ≈ 1 g. Does not correct residual syringe activity, extravasation, or uptake time. Different reconstructions change SUV_max.
Pitfalls
Activity is not counts. SUV needs the true injected activity, the residual, and the correct decay time — a clock off by 10 min on ¹⁸F is a several-percent error. Do not compare SUVs across reconstructions. Assumes 1 ml ≈ 1 g. Does not correct residual syringe activity, extravasation, or uptake time. Different reconstructions change SUV_max.
Keep this
C in kBq/ml, A in MBq, m in kg. Soft tissue ≈ 1 g/ml.
In this specialty