Keywords:
CT, Radioprotection / Radiation dose, Radiation safety, Dosimetric comparison
Authors:
C. Crowley, B. Carey, O. O’Connor; Cork/IE
DOI:
10.26044/ecr2019/C-3757
Methods and materials
Dose monitoring software (DoseWatch,
General Electric Healthcare,
Waukesha WI,
USA) was instructed to issue an alert (red alert) if twice the median dose for a particular CT protocol occurred.
The average dose for each protocol was automatically calculated by the software.
Figure 1 shows an example of the data made available by DoseWatch for a particular CT study.
Dose data from a single CT scanner (Discovery 750HD,
GE Healthcare) was gathered for an initial 6-month period (Period 1: 31st December 2014 to 30th June 2015) prior to the introduction of a justification feedback tool.
Following the initial 6-month data collection period,
all CT radiographers were taught how to access dose data and alerts,
and how to respond to these alerts and return feedback regarding the reason for the alert if this was known to the radiographer.
Implementation of the feedback tool was also accompanied by the provision of a dedicated computer in the CT suite to facilitate ease of access to dose data.
This tool notified radiographers of excessive dose exposures and gave them the opportunity to justify the reason for the increased dose.
Figure 2 shows the free text box available on DoseWatch for radiographers to enter their justification for red alerts in Period 2.
Following a second 6-month period (Period 2: 1st July 2016 to 31st December 2016) of dose justification,
radiation dose-related data were again gathered.
Two reviewers assessed all data for the causes of the alerts and compared findings with those of the radiographer reported justification.
An alert was considered false or justified where: the study was repeated; another study was added (without changing the protocol); the patient was large in size (considered where "large patient protocols" were utilized or when the radiographer commented on this using the feeback tool); and/or the study was mislabelled.
Where none of these criteria were met,
an alert was considered true.
The most common study descriptions associated with alerts were further evaluated for alert incidence,
the reason for justification,
and the proportion of true compared with false alerts.