Information for patients
This leaflet can be made available in other formats including large print, CD and Braille and in languages other than English, upon request.
The purpose of this leaflet is to explain the potential risks from the small amounts of radiation to which you will be exposed for your chest X-ray and lung scan.
It does not apply to other kinds of imaging such as ultrasound and MRI imaging.
Why am I having a lung scan?
Your healthcare team are concerned that you could have a blood clot in your lungs that may reduce your ability to breathe properly. This is a serious condition that poses a risk to you and your baby.
The lung scan will help confirm or rule out their suspicions which will affect the decision to recommend medication. Treatment with medication is itself not without a small amount of risk.
You will need to have a chest X-ray and then a nuclear medicine lung scan.
The nuclear medicine scan uses a small amount of radioactive substance to see where blood flows in your lungs. We may ask you to return the next day for the second part of the study where you breathe a radioactive gas so we can see where the air flows in your lungs. Alternatively, we may think it best to perform both scans on the same day. The radioactive substances may stay in your body for a short period of time.
The healthcare professionals involved always check that the benefit of having the test is greater than the risk from the small amount of radiation.
We will explain what the scan entails before we give you the radioactive substance.
Are there any risks to using radiation?
We are all exposed to background radiation every day. Any amount of radiation has potential ill health effects (very small increased chance of cancer); however, the amount used in these tests is minimal.
If you have one component of the lung scan, the amount of radiation you will be exposed to is about the same as you would naturally
receive in 6 months.
If you have both components of the lung scan, the amount of radiation is about what you would naturally receive in 1 – 2 years.
The lung scan and X-ray may increase radiation risks by a very small amount, less than 1 in every 6000.
|Hazard||Equivalent background radiation||Increased radiation risk||Risk level|
|Chest x-ray||Less than 1 week||Less than 1 in 100,000||Minimal|
|Nuclear medicine lun scan (perfusion only, separate day)||6 months||Less than 1 in 10,000||Very low|
|Nuclear medicine lung scan (ventilation only, separate day)||3 months||Less than 1 in 20,000||Very low|
|Nuclear medicine lung scan (ventilation and perfusion, same day)||1 to 2 years||Less than 1 in 6,000||Low|
What are the effects on my baby?
Exposure of an unborn baby to radiation may cause a slight increase in their risk from radiation. Your baby will receive an even smaller radiation dose than you will.
The risk from the blood clot is far greater than the risk from the radiation.
You must tell us if you are breastfeeding another child as we will need to give you personalised guidance.
What if I don’t have the test?
The greatest risk is an untreated blood clot. If you do not have the scan, your care team will likely recommend continued use of anticoagulants.
Without the lung scan, we will not know if these anticoagulants are unnecessary.
The very small dose of radiation in the lung scan is a much smaller risk than the unnecessary use of anticoagulants.
You should discuss any concerns with your healthcare team.
What if I have more questions?
Please talk to your doctor or any of the team carrying out your nuclear medicine test if you would like to discuss any of this further.
Further risk comparisons can be found at GOV.UK Guidance on Ionising radiation: dose comparisons.
Information produced by:
Northern Medical Physics & Clinical Engineering, North Tees & Hartlepool NHS Foundation Trust April 2023.
- Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources, Administration of Radioactive Substances Advisory Committee (2023).
- Radiation Risks from Medical X-ray Examinations as a Function of the Age and Sex of the Patient (HPA-CRCE-028), Health Protection Agency (2011).
- Ionising Radiation Exposure of the UK Population: 2010 Review (PHE-CRCE-0.26), Public Health England (2010)
Comments, concerns, compliments or complaints
Patient Experience Team (PET)
We are continually trying to improve the services we provide. We want to know what we’re doing well or if there’s anything which we can improve, that’s why the Patient Experience Team (PET) is here to help. Our Patient Experience Team is here to try to resolve your concerns as quickly as possible. The office is based on the ground floor at the University Hospital of North Tees if you wish to discuss concerns in person. If you would like to contact or request a copy of our PET leaflet, please contact:
Telephone: 01642 624719
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This leaflet has been produced in partnership with patients and carers. All patient leaflets are regularly reviewed, and any suggestions you have as to how it may be improved are extremely valuable. Please write to the Clinical Governance team, North Tees and Hartlepool NHS Foundation Trust, University Hospital of North Tees, TS19 8PE or:
Email: [email protected]
Leaflet Reference: PIL1431
Date for Review: August 2026