In the ‘UFO-Plan Vorhaben 3608S20001’ study initiated by the Ministry of Environment in Germany several phantoms, which are in use for Quality Control procedures in diagnostic radiology, have been investigated on accuracy and variation in production.
In this extensive study the principal investigator Dr. Borowski from the ‘Klinikum Braunschweig’ worked together with several workgroups from the ‘Physikalisch-Technische Bundesanstalt’, the ‘Bundesanstalt für Materialforschung und –prüfung’ and the ‘TÜV NORD Ensys Hannover GmbH’ to develop procedures for non invasive tests of the phantom components. These test procedures have been applied on a control samples for each of the phantom types.
One of the phantoms under investigation was the CDMAM phantom, which is recommended for use in the fourth edition of the European Guidelines for Breast Cancer Screening and Diagnosis (published in 2006) and its Supplement (in press). Within the above mentioned study 10 CDMAM phantoms have been evaluated with respect to the thickness and 5 CDMAM phantoms with regard to the shape/diameter of the gold discs.
The report concludes that the CDMAM phantoms are well built and that variations in thickness and size or shape of the gold discs with regard to the nominal values are mostly in the range of the manufacturer’s specified tolerances of 10% in thickness and 10µm in diameter.
However, the report also notes that the differences between phantoms may have an impact on the results of the analysis of CDMAM images. The report therefore suggests that, to further improve the robustness of the analysis, methods have to be developed, which compensate for these differences, for example by a calibration procedure.
Such a calibration procedure is already being investigated by the EUREF group. Images of a number of CDMAM phantoms have been made for this purpose and different methods of calibration are being evaluated. This work is still ongoing, but it is expected that the results of this evaluation will be available soon and communicated via the EUREF website.