A common Radiation Dose Monitoring System (RDMS) in combination with a Business Intelligence (BI) tool were used to monitor CT dose data. 104 standardised CT protocols per anatomical area and clinical indication, with defined DRLs, allowed for practice standardization across all centres. Each protocol corresponded to an RPID code from the Radlex Radiology Lexicon with defined number of series and scan area description.
Dose data were collected centrally using the BI tool. Data was analysed and actions for improvement of protocol parameters and examination technique were identified. High dose level alerts were tracked and justified using a justification coding method. Educational campaigns were organised for the radiographers and radiologists to increase awareness on Radiation Protection.
For this study, data from 2021 and 2022 was collected from a RDMS (DoseWatch, GE) connected to all CT scanners in combination with a Business Intelligence Tool (Imaging Insights, GE) used to monitor CT dosimetric data. 104 standardised CT protocols per anatomical area and clinical indication, with defined dose reference levels (DRL), allowed for practice standardization across all centres. Each protocol corresponded to an RPID code from the Radlex Radiology Lexicon with defined number of series and scan area description.
During the data collection process, the RDMS, identifies and categorizes the examinations according to the corresponding RPID and provides a detailed picture of the physical parameters (e.g. kV, mA, rotation speed, pitch, collimation, noise index, irradiation time/length, reference phantom size, iterative reconstruction ratio, etc.) and dose indices (CTDIvol and total DLP), as well as the patient's personal "data" (age, sex, weight and height, BMI).
Based on this information, radiographers can monitor examinations and modify CT protocol parameters in the future to avoid exceeding the Organizational DRLs.
Examinations with total DLP exceeding two times the RDMS calculated median DLP, or examinations with number of series 5 or above RDMS calculated p75 numer of series are flagged by the RDMS as examinations with high dose level alerts. High dose level alerts are generated for several reasons like: non-optimized protocol, selection of an inappropriate examination/ region, addition of an extra phase and/or region, overweight patient, prosthesis, motion artifacts and/or repetition due to a contrast material injection problem, etc. Scans with a higher dose level alerts can be justified by the operators, using the organizational justification coding list.
For non-optimized protocols, high dose level alerts are generated due to high CTDIvol and total DLP values. For optimized protocols, the root cause of a high dose level alerts is usually generated for high BMI patients or in case off additoional phase or additional region.
During the optimization process the following main parameters are taken in to account:
- mA
- kV
- noise index
- slice thickness
- rotation
- pitch
To achieve the organizational Dose Reference Levels in such a way that it does not negatively affect image quality, adequate feedback from Radiologists is required to approve the quality of the image.
Analyzing dosimetric data with the aid of the business analysis tools, we were able to observe which protocol needs optimization either for all centers, or only for one site. Or wether a specific radiographer needs further training. In this way we are able to monitor the studies with higher doses, and we can take steps to avoid overdose as well.
Our radiographers receive continuous training on dose reduction methods and on radiation protection topics.