Dental Fillings and — Artefacts on PET-CT

No. Removing fillings before a PET-CT is not necessary and not recommended. The radiologist uses the knowledge that metal is present to interpret the images, not to avoid them. What helps is telling the technologist before the scan exactly which teeth have metal and on which side. That information goes into the scan record so the radiologist reading the images knows what to expect.

'Limited assessment' means the radiologist could see that area but could not be fully confident in what they saw, because artefact affected the image quality. It is not the same as 'nothing was seen'. It means the read in that region is less reliable than in unaffected areas. Your oncologist will decide whether the limitation matters for your situation — sometimes the area of interest is far enough from the metal that it makes no practical difference to the plan.

Yes, if the cancer is close to a large crown or bridge, artefact can reduce how confidently the radiologist reads that area. It is worth raising directly with your oncologist before the scan. A crown next to the primary site or nearby lymph nodes is one of the more challenging situations for PET-CT to read clearly. Your team may plan for a supplementary MRI or clinical examination to assess what the artefact obscures. Any new finding needs biopsy confirmation before decisions are made from it.

Mainly the CT part. The bright streaks are caused by the way metal absorbs X-rays in the CT image. However, because the PET image is corrected using the CT data, errors in the CT can also affect how uptake is measured on the PET in that small area. The effect on PET is usually smaller and more localised than the visible streaks on CT, but in the area immediately around substantial metal both components may be less reliable.

MRI does not produce the same streak artefact as CT, which is one reason it is sometimes used to supplement a PET-CT when metal obscures a key area. However, dental implants and some alloys cause their own kind of distortion on MRI, so it is not a complete solution. MRI also does not measure metabolic activity the way PET does, so the two scans answer different questions rather than being substitutes for each other. A supplementary MRI is most useful when artefact affects a specific area that matters clinically for your situation.

If your dental work stays the same, the artefact pattern will be similar each time. This is actually useful: the radiologist reading your follow-up scan can compare directly with your previous images and know that a change in appearance near the metal reflects a change in the tissue, not a change in the artefact. Consistency matters in surveillance scanning, which is why your team keeps all previous scan images rather than only the most recent report.