Nuclear medicine is safe. The tracer delivers only a small radiation dose (a bone scan is about 5 mSv, similar to other higher-dose imaging), it's been used for more than 60 years with no known long-term adverse effects, and reactions to the tracer are extremely rare. The tracer fades within hours to a day and passes out in your urine. The main things to know are simple: drink plenty of water, and tell the team if you're pregnant or breastfeeding.
Key takeaways
- The dose is small; the benefit of the scan outweighs the low radiation risk.
- Over 60 years of use with no known long-term adverse effects.
- Reactions to the tracer are extremely rare.
- Drink water afterwards; tell staff if pregnant or breastfeeding.
The word “radioactive” understandably makes people pause. But nuclear medicine is a well-established, safe test — here’s the honest picture of the risks and the simple precautions.
A small dose, big track record
Nuclear medicine scans use only a small dose of radiation, acceptable for a diagnostic test, and the benefit of the scan outweighs the very low radiation risk.[1] To put a number on it, a bone scan delivers about 5 mSv — in a similar range to other higher-dose imaging, and roughly a few years of natural background radiation.[3]
Reassuringly, doctors have used nuclear medicine for more than 60 years, and there are no known long-term adverse effects from these low-level exposures.[1]
Reactions are extremely rare
Because only a tiny amount of tracer is used, allergic reactions are extremely rare and usually mild.[1] The injection may cause a brief pin-prick and, occasionally, slight redness. Always tell the team about any allergies or problems during previous scans.
The tracer clears quickly
The tracer’s radioactivity fades within hours to about a day through natural decay, and much of it passes out in your urine (and sometimes stool) in the first hours to days.[1] You’ll be asked to drink plenty of water to help flush it out.
As a simple courtesy in the first few hours, it’s sensible to limit close, prolonged contact with very young children or pregnant people; your department will tell you if any specific precautions apply. One quirky note: because you’re briefly slightly radioactive, security radiation detectors (for example at airports) can occasionally pick it up for a short time after some scans.[1]
Pregnancy and breastfeeding
Always tell your doctor and the technologist if you are, or might be, pregnant or breastfeeding, as this affects whether and how a scan is done, and whether breastfeeding needs a short pause.[1]
Frequently asked questions
How much radiation is in a nuclear medicine scan?
It varies by scan — a bone scan is about 5 mSv, similar to other higher-dose imaging. The benefit of the information usually outweighs this small risk.[3]
Will I be radioactive afterwards?
Slightly, and only briefly — the tracer fades within hours to about a day and passes out in your urine. Drinking water helps, and any special precautions will be explained.[1]
Are there side effects from the tracer?
Very rarely. Reactions are extremely uncommon and usually mild; the injection may cause a brief pin-prick or slight redness. Tell the team about any allergies.[1]
Sources
- RadiologyInfo.org (RSNA & ACR) — General Nuclear Medicine (benefits vs risks) — www.radiologyinfo.org/en/info/gennuclear
- RANZCR / InsideRadiology — Nuclear medicine (Cain) — www.insideradiology.com.au/nuclear-medicine/
- ARPANSA — Nuclear medicine and radiation doses — www.arpansa.gov.au/understanding-radiation/radiation-sources/more-radiation-sources/medical-imaging
