Metrology for diagnostic imaging using spectral computed tomography

Each year, 60 million European citizens receive computed tomography (CT) scans, where ionising radiation in the form of X-rays is used to diagnose a range of conditions including stroke, cancer and cardiovascular disease. Recently, Spectral CT (sCT) has emerged which performs scans at two different X-ray energy levels. By comparing differences in the images generated, it can better distinguish between tissue types and identify disease biomarkers, allowing improved diagnosis and opening the possibility of patient-focused treatments (personalised medicine).  However, variability in CT scanner types and a lack of standardised methods has made comparing results difficult. As sCT uses X-rays, it is also important that the dose delivered to the patient is safe, but the dosimeters used in CT have not been adapted to sCT. In addition, the Directive 2013/59/Euratom ensures basic safety standards are in place to protect both workers and patients, but sCT lacks the medical phantoms used to calibrate scanners, meaning patient health may be placed at risk.

This project will develop sCT phantoms which will be characterised in at least two National Metrology Institutes. Digital phantoms will also be designed and validated to support the derivation of uncertainty budgets. The phantoms (physical and virtual) will then be used to assess sCT variability between multiple clinical centres to allow imaging data protocols to be harmonised.

The work of speCTraMet and the guidance it develops will provide the first traceability for quantitative diagnostic imaging using sCT – allowing better treatment of patients whilst ensuring that their safety is paramount.