Tracer Leakage at the Injection Site — What Extravasation Actually Means

Not necessarily. A small amount of extravasation often does not affect the scan enough to require a repeat. The radiologist will assess the images and note in the report whether the quality was sufficient for a clinical decision. If it was not, your referring doctor will be told and a repeat scan may be arranged. You do not need to decide this yourself — the clinical team will advise you.

The swelling is fluid that has accumulated in the tissue, not injury to the tissue itself. The tracer is given in an amount far too small to cause chemical harm. The lump typically reduces over hours to a day or two as the body absorbs it. If the swelling grows significantly, becomes very painful, or does not settle within a day or two, contact the scanning centre or your oncologist.

No. The radiation dose from a PET tracer is very small even when it reaches the intended tissue. A localised leak does not deliver a dose to the surrounding skin that is considered clinically significant. SNMMI and EANM, the international bodies that set safety standards for nuclear medicine, are consistent on this point. The concern with extravasation is image quality, not radiation harm to the injection site.

Ideally, the technologist documents it at the time of injection and the note travels with the images. The radiologist can also often see it directly on the PET images as a focal area of uptake near the injection site. If you know extravasation occurred but are not sure it was recorded, tell the scanning centre before the images are reported so the note can be added while it still matters.

Not usually. Extravasation happens even when the cannula is placed correctly and every protocol is followed. It is more common when veins are small, fragile, or deep — factors the team does not fully control. The more useful question is whether it was documented and whether the images are still usable for a clinical decision, not where to assign blame.

More common than most patients realise. Published quality audits suggest a meaningful proportion of PET scans involve some degree of extravasation, much of it undetected at the time of injection. EANM guidelines include specific recommendations for detecting and documenting it precisely because undocumented extravasation is a recognised cause of degraded or misread images.

A warm compress applied to the area for short periods can ease discomfort and help absorption. The swelling usually resolves within a day. If it grows, becomes very painful, develops spreading redness, or has not improved after a day or two, contact the scanning centre or your oncologist. These signs are not expected with radiotracer extravasation and should be assessed promptly.

Tell them extravasation occurred, which arm it was in, and roughly how much swelling you noticed. If you know whether it was documented by the scanning team, mention that too. Your oncologist will consider this when reviewing the scan report, and if there is any uncertainty about the images, it helps them decide whether to request a repeat or correlate the findings with other information.