Precautions After a PSMA — or DOTATATE PET Scan

The rules are broadly similar, because FDG PET also uses a short-lived tracer — fluorine-18, with a half-life of approximately 110 minutes. The practical advice is nearly the same: fluids, toilet hygiene, and a brief buffer from pregnant women and young children. The bigger difference is between any of these diagnostic scans and therapeutic radioiodine, which involves far more radioactivity held for many days. If you have had an FDG PET before and followed those instructions, PSMA and DOTATATE precautions are comparable or slightly shorter.

Gallium-68 decays with a half-life of approximately 68 minutes. After several hours, the vast majority of the radioactivity has gone through physical decay alone, separate from how much your kidneys excrete. Drinking fluids speeds up excretion of whatever tracer remains in circulation. By the following morning, there is no meaningful residual radioactivity from a Ga-68 scan regardless of what you do — the physics ensures it.

Avoid prolonged holding — such as carrying a child on your hip for an extended period — during the first few hours after your scan. A brief hug or a short interaction is not a concern. After those first hours have passed, normal contact with children is fine. If you are unsure how much time has elapsed, check the injection time on your discharge notes — it should be written there.

No. Sleeping separately is a precaution for therapeutic radioiodine treatment, where large doses of I-131 are retained in the body for days. After a PSMA, DOTATATE, or DOTANOC diagnostic scan, the radioactivity is too small and too short-lived to require any change to your sleeping arrangements. Returning to your normal bed the same night is safe.

DOTATATE and DOTANOC are two different somatostatin receptor tracers used to detect neuroendocrine tumours. They bind to the same type of receptor on tumour cells but have slightly different molecular structures. Both are labelled with gallium-68, so the radiation physics — and therefore the after-scan precautions — are essentially identical. If your discharge sheet says DOTANOC rather than DOTATATE, follow the same advice.

Your nuclear medicine team or imaging centre will give you a written discharge sheet before you leave. This should state the tracer used, the injection time, and any specific timing guidance for precautions. At CION, PET and nuclear medicine scans are coordinated with partner imaging centres who provide this documentation. If you did not receive a sheet, or if something is unclear, contact the centre where you had the scan — not your GP or a general helpline — as they have your dose records and can answer precisely.

Fluorine-18 has a half-life of approximately 110 minutes — a little longer than gallium-68 at 68 minutes. The precautions are the same in type: fluids, toilet hygiene, and temporary distance from pregnant women and young children. Your nuclear medicine team may advise a slightly longer window before the precautions no longer apply. Your written discharge instructions should name the specific tracer and note any difference in timing.

At the doses used for diagnostic PSMA and DOTATATE scans, the radiation risk to you is very small. The effective dose is comparable to other imaging studies used in cancer care, and both the IAEA and EANM consider it acceptable in the context of diagnosing or staging cancer. Your oncologist would not request the scan if the clinical information it provides did not clearly justify that small risk. The brief precautions that follow are a standard safety measure, not a sign that the dose was large.