Scientific Guidance and Protocols

This document was developed by an EFOMP Working Group on “Angiographic and fluoroscopic systems - QC protocol” with the aim of providing guidance on Acceptance, Commissioning and Constancy performance testing over the life of an x-ray imaging system. The main motivation for this document is to provide Medical Physics Experts (MPE) with unified guidance across Europe on the assessment of dynamic x-ray imaging systems, in an area that currently lacks such advice. Current testing practice is quite disparate, with specific and varied performance criteria being applied from country to country. It can be difficult for manufacturers to meet all of these different requirements and the introduction of a standardised protocol should simplify the situation, ensuring a consistent and comprehensive set of tests. Image quality assessment of these systems has always been a challenge, given the dynamic nature of the images and the fact that a visual evaluation often had to be performed ‘on the spot’ by the MPE. There have been a number of developments in the area of image quality assessment using computational methods and a further aim was to provide information on this topic.

This document provides guidance for testing dynamic x-ray systems. We will use the term ‘dynamic x-ray imaging system’ as a blanket term, covering simple mobile fluoroscopy to complex angiography devices. Not covered is the testing of cone beam computed tomography (CBCT) modes also referred to as 3D rotational angiography (3DRA) imaging. In these modes, the x-ray tube/detector assembly is rotated by at least 200° around the patient as a number of low dose projection images are acquired. These are then reconstructed to generate a volumetric dataset. Clinical applications include planning in stereotactic radiosurgery and angiography examinations such as imaging of aneurysms in neuroradiology and the evaluation of stent placement (Doerfler et al., 2015; Fahrig et al., 2021). Guidance on testing these systems is available in a separate EFOMP protocol (de las Heras Gala et al., 2017).

The complexity of PET imaging requires a clear quality control procedure at different levels, from radiopharmaceutical activity assay up to the final image formation and quantitation.

The EFOMP Protocol for Quality Control in PET/CT and PET/MRI provides simple and practical procedures that may be integrated into clinical practice to identify changes in the PET/CT/MRI scanner's performance and avoid short- and long-term quality deterioration.

The Protocol describes the quality control procedures on radionuclide calibrators, weighing scales, PET, CT and MRI scanners using selected and measurable parameters that are directly linked to clinical images quality. It helps to detect problems before they can impact clinical studies in terms of safety, image quality, quantification accuracy and patient radiation dose.

CT and MRI QC are described only in the context of their use for PET (attenuation correction and anatomical localization) imaging.

A regular QC based on the proposed protocol would guarantee that PET/CT and PET/MRI scanners operate under optimal conditions, resulting in the best performance in routine clinical tasks.

EFOMP intends to update the protocols after few years in practice, taking into account the knowledge and experience gained via their implementation in different clinical settings. Users are encouraged to share their experiences at conferences and in publications. Please submit comments and recommendations to the EFOMP PET/CT/MRI QC Working Group chair Roberta Matheoud (roberta.matheoud@maggioreosp.novara.it) once you’ve used the protocols.

EFOMP GUIDELINE "Quality control in PET/CT and PET/MR" - software tools user manual PET/CT QC - Python scripts were prepared by the EFOMP Working Group (WG) on "PET/CT and PET/MR QC Protocol".

Quality control of Digital Breast Tomosynthesis (DBT) systems is an essential part of quality assurance to periodically check that quality requirements are met and radiation exposure levels are sufficiently low. The main purpose of this document is to present procedures for quality control of DBT systems. In the document the new breast dosimetry is incorporated. The software required to calculate glandular dose in the DBT protocol can be found here: https://aapm.onlinelibrary.wiley.com/doi/full/10.1002/mp.16842

EFOMP provides links to software of third parties for the convenience of the users of the protocol, but does not guarantee the proper working of the software.

• https://data.mendeley.com/datasets/8jj7865wfn/ (Plugins for QC compliant with the European guidelines and EUREF/EFOMP protocols for digital mammography and digital breast tomosynthesis)
• https://medphys.royalsurrey.nhs.uk/nccpm/?s=tomosynthesisqctools (For extracting planes out of a DBT stack, partial opening of DICOM stack, measuring distortion, z-resolution and flat fielding)

Software to determine glandular dose according to the new AAPM/EFOMP breast dosimetry model is available here: https://aapm.onlinelibrary.wiley.com/doi/full/10.1002/mp.16842

Test patterns for quality control of the display of images on a workstation can be found at 

• https://www.aapm.org/pubs/reports/OR_03_Supplemental/ (Test patterns from AAPM taskgroup 18)

Quality control of cone-beam computed tomography (CBCT) systems is an essential part of quality assurance to periodically check that quality requirements are met, reduce uncertainties and errors and reduce the likelihood of accidents and incidents. Radiation exposure levels must be measured to ensure that patient doses associated with CBCT examinations are kept as low as reasonably achievable consistent with the required diagnostic information. The main purpose of this document is to present procedures for quality control of CBCT systems used for dental, radiotherapy, interventional radiology and guided surgery applications.

An executive summary of the full EFOMP CBCT protocol has been published in the European Journal of Medical Physics, and is available for free download at the following link: http://www.physicamedica.com/article/S1120-1797(17)30183-7/fulltext

It is the intention of EFOMP to update the protocols every few years taking into consideration the experience gained through their implementation in different settings. EFOMP encourages users to report their experiences at conferences and in publications. Once you have used the protocol, please send comments or suggestions to: Alberto Torresin: alberto.torresin@unimi.it.

This document is the first of the series on quality control and has concentrated on the need for harmonization of quality controls in (QCs) digital mammography.  In particular it proposes tests that can be applied by each country with the resources available locally, accepting the fact that there are different technological levels across the European countries and it fulfils the following criteria:

1. Tests included in the protocol have been selected on the basis of their relevance/priority (“Keep it simple”).
2. The protocol should be applicable to any type of digital mammography system (DR and CR).
3. The protocol should be “compatible” or at least “not in contradiction” with other existing protocols.
4. The protocol should not require the use of a specific test object, and consequently, should be “tolerant” about image quality parameters and criteria.
5. The protocol should be widely applicable and adaptable to local regulations.
6. The protocol should provide clear instructions about each test procedure, in order to minimize the potential for misinterpretation.

An article of the EFOMP Mammo protocol has been published in the European Journal of Medical Physics and is available for free download at the following link: https://tinyurl.com/y8zyearl

It is the intention of EFOMP to update the protocols every few years taking into consideration the experience gained through their implementation in different settings. EFOMP encourages users to report their experiences at conferences and in publications. Once you have used the protocol, please send comments or suggestions to: Alberto Torresin: alberto.torresin@unimi.it.

You are kindly asked to complete the on line survey on the EFOMP Mammo Working Group protocol at: https://goo.gl/XuZEBJ.