Bayer HealthCare explains how its Radimetrics solution can help maximise your return on radiation compliance with dose management.

Founded in the broad success and adoption of diagnostic imaging tests, medical exposures have evolved into the dominant man-made source of radiation to the population. By 2006, it was found to match, on average, the annual background level for the US population. Individual patient exposures can accumulate to equate to multiple years of background. The associated risks have led to a raised sense of responsibility, and a desire for dose awareness and management.

Together with advancing regulation, dose management is becoming a necessity for imaging departments today. However, implementation still seems to closely follow legal pressures, as studies suggest. What if compliance with regulation actually translated into tangible benefits for patients and providers?

A starting point for imaging dose criteria is first appropriateness and then the ALARA – ‘as low as reasonably achievable’ – principle. Further standards, initiatives and regulations are complementing this principle with more formal and specific objectives. These include: Euratom Directive 2013/59, EuroSafe and PiDRL initiatives, Image Gently and Image Wisely initiatives, and Dose Registry initiatives. So what can be done to achieve this and what are the key requirements?

Patient dose reporting: tackling outliers
The Euratom Directive specifies a rudimentary dose-reporting capability at the patient level. For example, Article 58 of Euratom demands that patient exposure information is documented in the diagnostic report. Article 60 specifies that interventional radiology and CT equipment need to provide parameters of patient dose and transfer the data to the exam record. Further, Article 63 requires reporting of accidental or unintended exposures and other significant events to authorities.

Since most scanners are providing DLP information of scans on the dose sheet, this information can be stored in PACS. However, a statistical evaluation across multiple patients is not easily possible due to the nature of the image archive. Also, an investigation of root causes and correlations for correctivemeasures may be difficult.

Enterprise dose management: you can only manage what you can measure

Therefore, when evaluating data beyond the individual patient record, dose tracking and management functionality becomes necessary. Corresponding objectives are covered in Article 58, which specifies clinical audits to be performed and corrective action if DRLs are consistently exceeded. Further, Article 61 demands appropriate techniques, corresponding quality-assurance programmes and dose assessment in the context of paediatric imaging, screening programmes, and potential high-dose procedures in interventional radiology, nuclear medicine, CT and radiotherapy.

Why all this effort? The answer can be found in Article 56: it again states the ALARA principle and use of DRLs, and, most importantly, demands "consistent production" of diagnostic information.

How else could outliers be reduced and DRLs complied with? How else could an ALARA dose be replicated for the next patient? In other words: how can dose be avoided that does not add to diagnostic information? The key is to reduce systematic variations in the imaging process. These variations stem from sources such as protocol and scan range selection. Variation levels have been found to exceed 200% between operators for the same exam. DRLs, protocol harmonisation and training have been demonstrated to reduce dose levels by 40-80%.

So, once again, it holds true that you can only manage what you can measure; aggregate statistical methods are needed that look beyond the individual patient file. The results are equally impressive and encouraging.

The consistent quality of connected radiology
So how can institutions prepare for the imminent radiation dose regulations and, at the same time, benefit from advances in patient care and reproducible quality?

As pioneer in the field, Bayer’s Radimetrics (Radiology Metrics and Quality) solution provides a vendor-neutral platform to help with compliance automation by facilitating protocol management, email dose alerts, interactive dosimetry training and providing reporting templates for dose submissions to authorities already today.

Beyond radiation dose management, it offers sites room to grow with future needs by also being able to personalise, track and manage contrast dose**, by expanding into non-ionising modalities for comprehensive utilisation tracking, and supporting dose registry set-up and participation for benchmarking or research.

One particularly interesting case in point is University Hospital of Basel (USB) in Switzerland. USB has voluntarily chosen to stay ahead of legislation and become a beacon of excellence in radiology. Since the installation of Radimetrics in 2012, USB has raised the bar in patient care and reproducible quality.

Personalised care: dose alerting
USB has set a threshold dose value for each CT protocol using the volumetric CT dose index (CTDIvol). By tracking the patient-effective dose, the site aims to avoid unnoticed periodic CT scans in young patients and patients with non-malignant disease, especially when non-ionising imaging modalities can deliver equivalent diagnostic information. In the case that a patient exceeds the threshold dose, the information is passed on to the radiology information system so the radiologist is alerted ahead of the next scan and can consider an alternative imaging modality.

In addition, dose outliers are monitored at the examination level to observe early systematic errors, such as an unintentional selection of the wrong technical settings. This allows timely corrective measures.

Personalised care: scanner benchmarking and patient triage
USB also performed scanner benchmarking on dose effectiveness. The average effective dose for a routine CT of the chest differed up to fourfold among the scanners. Having this important information at hand, young patients are now triaged for a routine CT of the chest to USB’s two high-end CT scanners with the goal to deliver the lowest doses for this radiosensitive patient group. These findings also helped inform a new high-end scanner acquisition in 2014.

Reproducible quality: protocol management
The systematic collection of dose data for different CT protocols based on hundreds to thousands of CT studies opened the door for further benchmarking and optimisation efforts, with the goal being to achieve the lowest possible dose for patients while maintaining diagnostic accuracy.

Based on the optimisation of technical parameters, the most common protocols were significantly improved. The most dramatic reduction in average dose was achieved for routine chest CT with or without contrast media. Effective dose for a routine CT of the chest was reduced by 63%, from 5.5mSv in 2012 to 2.0mSv in 2014.

As part of its continuous commitment to patient-centred care, USB also compares with external benchmarks and found the average SSDE for chest CT to be 45% below the national DRL for Switzerland.

Reproducible quality: reduced variation
Over the same time frame, reproducibility of doses between scans was also greatly improved across protocols as seen in the tighter distribution bands (see image above right).

References available on request.