Bit by bit30 October 2018
In ongoing efforts to reduce radiation exposure to patients and healthcare professionals alike, how big a role might a new generation of radiation dose monitoring software have to play? The UK’s National Institute for Health and Care Excellence (NICE) has developed a Medtech innovation briefing, inviting input from industry specialists on existing and incoming measurement techniques.
The use of radiation dose-monitoring software may improve the collection, analysis and reporting of radiation dose data compared with current manual or semi-automated methods. The detailed information provided by dose-monitoring software allows the best image quality possible, while minimising radiation exposure to the patient.
Dose-monitoring software can be used to alert healthcare professionals to radiation exposure when diagnostic reference levels (DRLs) are consistently exceeded. Some of the technologies may help facilitate management of protocols, contrast media and staff dose as well as image quality.
The systematic monitoring and analysis of radiation dose data can potentially reduce radiation exposure for people having multiple imaging procedures. It can help hospitals meet legal and policy requirements. Based on ‘Medical exposure directive 97/43’, in some European countries (currently including the UK), radiation protection legislation mandates the recording of individual patient doses (or parameters from which dose can be calculated). Current UK legislation includes ‘Ionising radiation (medical exposure) regulations 2000 (IRMER)’ from the Department of Health, which details DRLs and what to do in cases of excessive radiation exposure. Systematic dose monitoring may help to support quality assurance in terms of meeting directives such as the ‘EU Council Directive 2013/59/EURATOM’.
Current guidelines and arrangements
Public Health England currently gathers radiation dose data for common examinations from a sample of UK hospitals through manually compiled databases. The Department of Health’s response to COMARE’s 16th report on the increased use of CT scans in the UK recommended that more frequent UK dose surveys need to be done. These surveys will provide data to support regular updating of national DRLs, including those specifically for children.
Manual and semi-automatic recording of radiation dose data requires data entry in the radiology information system, a spreadsheet or on paper. This is timeconsuming and may result in an error rate of up to 6%, according to a 2016 research paper on the matter.
The 2011 review of the Public Health England report ‘CRCE-013: Doses from CT examinations in the UK’ specifies that for a national audit on radiation dose data, a healthcare professional (either a radiographer or a physicist) with access to PACS should acquire the data.
It is the data manager, whether they be a radiographer or a physicist, that should verify the data before transferring it to a record.
The technologies could used for retrospective analysis by healthcare professionals specialising in radiation protection and with appropriate training. These would most likely be medical physicists, radiographers and radiologists. The technologies would be used in secondary care in the NHS to record and analyse data in the trust. Radiation dose data can be collected from anyone undergoing medical imaging with ionising radiation.
Cost of standard care
The main cost associated with manual dose data recording is the clinical time it takes. The cost of a hospital radiographer’s time is £35 per hour and a medical physicist’s time is £56 per hour. This includes all remuneration, qualifications, department overheads and capital costs. The cost depends on whether data is recorded manually (by radiographers filling in forms) or downloaded from the radiology information system. Specialist commentators estimate that it takes 20 minutes of a radiographer’s time for data collection per examination. The data is then transferred to a medical physicist for verification of data entry, review, analysis and report production. This takes at least one hour per examination. Combining the radiographer’s and medical physicist’s time, the estimated average cost is £68 per examination.
If data is instead taken from the radiology information system, little or no radiographer time is needed. However, extra medical physicist input may be needed to understand the data, eliminate outliers, confirm the validity of results and remove zero values before the data can be analysed.
One specialist commentator estimated that this is at least 1.5 hours of a medical physicist’s time is needed for each individual examination, with an estimated average cost of £84.
If adopted, the technologies would likely be used with the available ionising radiation imaging equipment. A mid-sized hospital trust could have an average volume of 100,000 images per year, whereas a large trust may do 250,000 images per year.
These technologies are software packages to be used with current hardware and so no additional facilities or technologies are likely to be needed. However, the hospitals will need to reallocate staff to manage information governance and software compatibility arrangements such that the technologies can be properly installed and used. This may prove to be time-consuming. The technologies will need IT involvement to set up and staff to maintain them. No published evidence on the resource consequences of adopting the technologies was found, including either economic evaluations or costing studies.
Comments on monitoring technology currently available were invited from clinical and scientific experts working in the field and relevant patient organisations. The comments received are individual opinions and do not represent NICE’s view. All five specialist commentators were familiar with these technologies. One specialist used at least one of the technologies infrequently (approximately five times per year); another used them regularly (on a weekly or monthly basis).
Two specialists stated that the radiation dose-monitoring software technologies are a minor variation of current technology, automating an existing process by using modern IT standards to interconnect imaging devices with data collection devices. Four commentators thought that the technologies could potentially improve data collection and image quality, and minimise radiation doses. One of the specialists stated that the technologies are a significant development in allowing real-time evaluation of all systems in an organisation, helping to identify imaging systems in which problems may be developing.
All but one specialist commentator thought that some level of training would be needed to use the software.
Potential patient impact
Three specialists anticipated that the technologies would have little or no direct effect on patients. However, three other specialists felt that the software could reduce overall population radiation exposure by allowing regular reliable audits, which would improve patient safety and reduce risk. Two specialists stated that the technologies would particularly benefit young people, and one felt that they could help to identify people with chronic conditions who have repeated examinations and therefore radiation exposure.
Three commentators thought that using the technologies could improve diagnostic accuracy and confidence, which would benefit patients. One stated that they may enable higher radiation doses to be used where appropriate to increase image quality. Another specialist stated that an alert system to identify relevant previous imaging might reduce a very small number of unnecessary examinations.
Potential system impact
The commentators agreed that the technologies would help to optimise images, which would be beneficial for the healthcare system. Three specialists felt that the automation would ease the burden of the current manual process of recording dose-monitoring data. One specialist stated that the technologies would help identify variation in techniques within or between institutions, highlighting the need for optimisation of radiation dose and image quality. Two commentators stated that using this software would lead to multidisciplinary teams optimising their work, possibly reducing the amount of time spent by the team on analysing patient dose data. However, another commentator expressed doubt that the additional information would reduce time spent by medical physicists on collection, analysis and reporting, stating that more time will be needed for analysis and interpretation. One of the commentators added that additional staff resources would be necessary for maximum benefit from the systems.
All the specialist commentators acknowledged that the database system would need to connect to existing IT infrastructure: some systems would be able to work with existing IT infrastructure with minimal changes and updates, whereas others may need a larger investment (for example, an increase in server capacity).
Four specialists thought that the potential for NHS cost savings was unclear, and one stated that a detailed cost analysis would be necessary to assess the cost implications. Another commentator stated that the financial savings would be minimal, because the technologies provide quality improvements rather than significant cost savings. One specialist stated that although dose-monitoring systems may make data recording faster, the process is likely to include more examinations than would have been included with manual data entry. Another explained that some people may choose to pursue legal action over WWexcess radiation exposures, so the technologies could reduce legal costs.
One specialist noted that the Public Health England report called for patient-size measurements to be taken from the images, because this information is rarely available and is a significant factor in terms of variation in radiation dose; the commentator did not feel that dose monitoring technologies would eliminate this manual step. Two specialists noted that dose monitoring systems are most useful if they are connected to multiple modalities, information systems and shared across organisations.
One commentator stated that regional or national dose collection would be needed for setting and optimising interventional DRLS; the potential for collection of large scale data offered by these technologies could transform the insight available. Another commentator expected the evidence to be generalisable across all technologies because the handling of data will have more of an effect than the technology itself.
According to another Public Health England report, ‘Medical and dental X-rays: frequency and collective doses in the UK’, 26% of medical imaging examinations with ionising radiation are for dental purposes and, the software will not be able to analyse most of these.