The aim of quality control in mammography is to maximize the benefits of exams while minimizing their potential risks. By law, mammogram screening programs must include quality control measures. In fact, ongoing internal quality controls provide a sound foundation for clinics to pass external reviews, such as audits and certifications, with flying colors. So, how can clinics maintain consistently high standards in mammography, and how can innovative technology such as artificial intelligence (AI) help? In this blog, we’ll provide a helpful overview with six practical tips on how to achieve this.

Why quality controls in mammogram screenings are crucial

Mammography is an X-ray-based exam of the female breast that provides information on the condition of the breast tissue and any pathological changes. These days, digital mammogram systems have become the norm. While mammograms are used to clarify specific clinical symptoms (curative mammography), they are also used for early breast cancer detection in asymptomatic women (mammography screening).

The aim of mammogram screening is to detect breast cancer and its precursors at early, prognostically favorable stages. At the same time, however, the – predominantly healthy – participants should be exposed to as little as possible X-ray radiation, and not be mis- or over-diagnosed. Here, the key is strict and systematic quality controls. Having standardized controls in place can also increase the acceptance and willingness of eligible women to participate in these screening programs.

Over the last twenty years, numerous professional associations have developed protocols for quality controls in mammography. Among the best known are the guidelines of both the European EUREF and the American College of Radiology (ACR), as well as the manual by the International Atomic Energy Agency (IAEA). However, these guidelines vary in their scope and their specific requirements.

In the US, for example, the Mammography Quality Standards Act (MQSA) defines the minimum quality standards required for mammogram screening used in early breast cancer detection. Essentially, the Act is based on ACR specifications and outlines consistent internal quality management as well as regular external audits. Of course, there are minimum requirements for radiation protection and medical-technical quality that also apply to curative mammography.

Levels of quality control in mammogram screenings

Quality controls in mammography are not just a one-time task – it’s vital that there is consistent control and improvement of standards. These controls are carried out on three levels:

Structural quality

Structural quality refers to requirements for material and staff, as well as for the greater working environment. For mammograms, this encompasses the space and equipment used by the relevant facilities. Constancy tests help ensure quality control; these are regular physical-technical checks on machines that are approved for operation. Another aspect of structural quality controls in mammography is standards for all staff involved, which includes having the right professional qualifications, carrying out further training, adequate experience measured through minimum case numbers, and regular checks.

Process quality

Process quality refers to the quality of all procedures and processes involved. In the case of mammograms, process quality controls ensure standards such as double reporting and multidisciplinary case conferences, wherein a patient’s exam results are discussed by the whole team. In addition, internal random checks can verify the quality of exams, reporting and further diagnostic steps.

Quality of results

The third level of quality controls in mammography is the evaluation of the result quality for mammograms. Result quality encompasses various indicators, such as image repetition rate or the rate of interval carcinomas. Core aspects of quality controls relate to external certifications by mammography institutions, as well as internal quality reporting.

Key components of internal quality controls

Internal quality controls form the foundation for clinics to maintain high standards for mammogram screening. The goal is to identify and correct any possible or present deficiencies early on, before these can impact the quality of medical care. Internal quality controls for mammography include the following aspects:

  • Image quality controls: Deficiencies in image quality are often due to operator errors during the examination (e.g., suboptimal positioning or compression of the breast). Only professionally made mammogram images can be correctly evaluated. As a rule, radiologists responsible for the facility’s screening program must carry out random checks on the diagnostic image quality provided by each medical technologist. In Europe and the US, assessments are usually based on the PGMI classification, made up of four quality levels (perfect, good, moderate, unacceptable). In addition, the number and proportion of repeated images are statistically evaluated.
  • Physical-technical quality controls: Once mammogram equipment systems have been green lit for operation, checks at regular intervals are crucial to ensure consistently high image quality, but with low radiation exposure. Regular constancy tests are carried out under standardized conditions to test the following:
    • Technical image acquisition quality (including verification of the radiation dose)
    • Image processing
    • Image display (includes checks of monitors and printers)
  • Quality controls for reporting: Physicians responsible for the screening program must evaluate the proportion of carcinomas detected, as well as the rates of false-positive and false-negative findings made by all radiologists. These results are then discussed in peer review meetings. Biopsies or histopathological examinations performed by the radiologists themselves also have to undergo regular evaluation checks.

6 Tips for physical-technical quality controls in mammography

Every radiology clinic is responsible for physical-technical quality controls in their mammography department. It’s a crucial prerequisite for consistently high image quality alongside low radiation exposure for the patient. So that these quality controls are fit for purpose, radiology clinics must be aware of these essential aspects:

1. Ensure sufficient time and staff

Staff need to have sufficient time to properly perform and document the relevant quality controls and to remedy failing standards as necessary. Ideally, quality controls in mammography should be a multidisciplinary initiative, involving both medical and medical-technical staff. It’s also crucial to clearly define responsibilities within the team – that is, who performs what checks and when. In addition, all staff should know the relevant contacts in the event of problems or breakdowns.

2. Equipment constancy tests at regular intervals

Once green lit for operation, mammogram equipment systems must be checked at regular intervals to ensure consistent image quality and radiation exposure. These constancy tests are usually performed on-site by radiologists. Depending on the quality control protocol, some tests must be performed daily, while others are weekly or monthly. A comprehensive check and maintenance of all system components is typically carried out once a year by medical techs.

Each mammography facility should have a reference document in which the frequency of the individual checks and the respective tolerance values according to the mammography quality assurance protocol are noted. In addition, concrete measures should be defined here that are to be initiated in the event of deviations from the standard.

3. Use standardized test materials for quality controls in mammography

For the constancy tests in mammography quality assurance, a set of test specimens or phantoms is required, which serve as weakening specimens in the test images. Test inserts are used, among other things, to check the detectability of the smallest structures. Today, PMMA plates with various object thicknesses are generally used. It is essential that the test materials are CE-certified and comply with the current test standards as defined in the EUREF or ACR guidelines. Non-standard test specimens could lead to deviating conclusions.

4. Ensure consistent audit requirements

Equipment settings and test equipment should be kept constant for all mammography quality assurance checks to ensure comparable results. According to current guidelines, the tests must also be performed under the same conditions as in medical practice (e.g., mode of automatic exposure, image display).

5. Identify and rectify systemic errors and defects

If the constancy tests reveal any defects or errors, then a systematic approach can find the causes and eliminate them as quickly as possible. The aim is to swiftly gain ideal image quality and to keep equipment downtimes to a minimum.

A part of effective systematic troubleshooting is the use of checklists and flowcharts, which help narrow down possible causes. They then guide you on the next targeted steps.

For example, when interference structures occur, the following criteria could serve as a starting point for error analysis:

  • Can you delineate the shape of the interfering structure? If yes, is it:
    • Point-shaped
    • Oblong
    • Or irregular?
  • Does the position of the interfering structure remain unchanged?
  • Does the interfering structure affect the entire image area?

Depending on the specific constellation, extra quality controls may, for example, be put in place to check the adjustment technology, or to clean the freely accessible components of the mammogram machine, or even to recalibrate the system.

6. Use modern software tools for quality controls in mammography

To facilitate and automate physical-technical quality controls in mammography, special software tools are now available. These guide users through the individual steps, making the exam process much easier and faster. This does away with old-fashioned manual data acquisition and evaluation forms, which can be time-consuming as well as error-prone.

Outlook: Artificial intelligence (AI) for more effective quality controls in mammography

AI-based technologies are increasingly being used in modern medicine, with radiology pioneering their efficiency. When it comes to complex image analyses, self-learning algorithms are especially beneficial: They can efficiently evaluate large amounts of data according to objective criteria, saving time while doing so.

Thus, AI-based software systems are predestined for use in quality control, to further improve mammograms. They have many applications: self-learning systems are already helping radiologists when reporting on mammogram images as additional controls or by pre-categorizing the images. Overall, AI has helped radiologists prioritize their focus.

AI can also be used further upstream to automate image quality evaluation. This helps medical technicians gain immediate feedback on whether an image meets the required standards.

In mammography quality control, another application of AI is for physical-technical constancy tests. Usually, radiologists review a portion of the phantom images to assess the detectability of small structures. With the aid of AI-based software systems, this step can be automated based on objective criteria. AI apps can reduce error rates in the future, facilitate practical procedures, and maintain consistently high standards – even when waiting rooms are full and staffing levels are tight.

The optimization potential for quality controls

Over the decades, mammogram screening has significantly reduced breast cancer mortality. Yet, to ensure that screening exams have the best cost-benefit ratio, quality controls have to be a top priority. Many radiology clinics can improve and optimize their internal quality management by focusing on even more consistent standardization and process automation. Modern technology can lead the way and provide valuable support.