• Question: If perhaps a sufficient amount of metal were to be located in the individual taking the scan, what health risks could it possibly impose and does it affect the quality of the image?

    Asked by Shania to Clare, Glafkos, Paul, Samantha on 16 Mar 2015.
    • Photo: anon

      anon answered on 16 Mar 2015:

      People who have metal in their bodies will cause an artefact. For example in MRI is someone with a metal hip their image of their hip would be black. But if you are scanning someone with a metal hip but want to take a picture of the brain there shouldn’t be any problem. However, the patient is warned that they will experience a slight tug in the MR scanner but it is nothing to be worried about!

      SO when you go for MR scan you are asked about implants etc as it may affect the area to be imaged.

      Great question!

    • Photo: Clare Devery

      Clare Devery answered on 16 Mar 2015:

      If you’re talking about an MRI scan then yes, as Pauline has said, there will be an associated artefact. This is because an MRI scanner works using a giant magnet. If you bring metal near the magnet you will have an impact on the invisible magnetic field surrounding the magnet, and the scanner won’t work as it was designed to!

      This is not the case for other types of scan though. The likes of an x-ray or CT examination could go ahead without any safety concerns for the patient. Again though there might be an artefact in the images that would worsen image quality.

    • Photo: Samantha Terry

      Samantha Terry answered on 16 Mar 2015:

      see answers above – I didn’t know the answer to this one!

    • Photo: Paul Booker

      Paul Booker answered on 16 Mar 2015:

      I won’t comment on MRI scans but in radiotherapy we quite often have to scan and treat people with artificial hips or metal fillings. We use CT scans to plan our radiotherapy treatment and metal causes lots of streaking in the image, so we have to go carefully through and overwrite those bits with a standard body density. This also upsets the dose calculations in radiotherapy, so we try to avoid putting any radiation beams that will enter or exit through metal.

    • Photo: Glafkos Havariyoun

      Glafkos Havariyoun answered on 16 Mar 2015:

      I agree with answers above for CT and MRI. In Nuclear Medicine there is not health risk associated with having a scan with metal inside a patient. Small artefacts (something observed in a medical scan that is not naturally there but occurs due to a presence of another thing (i.e. metal or due to the procedure) can be seen though as well.

      Also in MRI there have been reported cases of burns due to forgotten leads on patients or clothes with silver lining!

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