[VEILLE] The impact of acceleration factors in 4D flow MRI
The decision of January 15, 2020 applies from January 15, 2021.
Interest of the study
In the event of a tube change, the decision provides for the following tests to be carried out as part of the IQC:
- - 8.5.1/8.12.1 "Determination of acquisition parameters" using PE and PMMA sheets with thicknesses of 2.5 mm, 5 mm and 10 mm (240 mm x 320 mm)
- - 8.5.6/8.12.2.2 "Half-attenuation layer" and 8.5.8/8.12.6 "Mean glandular dose" with the use of a multimeter and, where appropriate, aluminum plates with dimensions of at least 10 cm x 10 cm. However, it is not compulsory for the operator to own this equipment, given the expected low frequency of such changes. When carrying out these tests, the equipment of the service provider who changed the tube can be used.
These tests should also be carried out when a software version is changed, modifying the projection dose.
Interest of the study
From now on, a new control is to be carried out internally: 8.12.5.4 (Homogeneity of reconstructed tomosynthesis image and SNR monitoring).
The decision allows the use of a 45 mm thick PMMA block if the dedicated mammography calibration block supplied by the manufacturer is to be used at tube level. A set of PMMA sheets with a total thickness of 45 mm can also be used.
It should also be noted that the dimensions of the PMMA block or 45 mm thick sheet assembly are 240 mm x 320 mm. In other words, if the manufacturer’s calibration phantom is to be used at Potter level, it must be used for IQC.
The decision mentions the software needed to check receiver homogeneity, the homogeneity of the reconstructed tomosynthesis image and SNR monitoring, and to check for uncorrected defective elements, as mentioned in point 8.12.5.4. In fact, as part of internal quality control, only the test of reconstructed tomosynthesis image homogeneity and SNR monitoring mentioned in section 8.12.5.4 requires the use of software. In particular, this software can be made available by the manufacturer on the acquisition console of the mammograph or plate reader.
If this is not the case, you can use the Flatfield software proposed by the LRCB and available on the ANSM. If the software is not available on site, the EQC cannot issue a non-conformity on this point, pending installation of the software.