JACR: MDCT radiation dose slashed by optimization workshops
Anthony Wallace, MS, medical physicist at the Australian Radiation Protection and Nuclear Safety Agency in Yallambie, Australia, and colleagues collected data relating to radiation dose delivered by multidetector CT scanning at 10 hospitals and private practices in Queensland, Australia. The researchers sought to test various methods for dose optimization training, including audit feedback and didactic, face-to-face, small-group teaching of optimization techniques to learn which would be the most effective.
Data were collected for a variety of common adult and pediatric CT scanning protocols at the 10 sites, including tube current–time product, pitch, collimation, tube voltage, the use of dose modulation and scan length. One radiologist and one medical imaging technologist responsible for the project at each participating practice then participated in a one-day feedback and optimization training workshop conducted by the Royal Australian and New Zealand College of Radiologists and supported by the local state health department.
The feedback workshop deidentified the data collected and offered an analysis and discussion of the factors contributing to dose for higher dosing practices for each protocol, explained the authors. Following the optimization training, data were once again collected to track changes to radiation dose at each facility.
In total, data for 1,208 scans were collected during the first collection period and data from 1,153 scans were gathered during the postoptimization dose collection period for the four adult protocols (non-contrast brain CT, CT pulmonary angiography, CT lumbar spine and CT urography).
The researchers reported that for each of the four protocols, an average decrease in effective dose was successfully achieved. Specifically, average reductions of 46 percent were noted for brain CT, 28 percent for CT pulmonary angiography, 29 percent for CT lumbar spine and 24 percent for CT urography.
Citing a limitation to their research, it proved impossible to collect valid pediatric data from most sites due to the small numbers of children presenting for multidetector CT, and phantom data were acquired during the preoptimization and postoptimization phase, the authors noted. However, substantial phantom dose reductions were demonstrated at all sites, they said.
Despite the optimistic findings, access to medical radiation physicists, assistance with time-consuming data collection and technical support from a medical imaging technologist were costly, but critical to the success of the program, Wallace explained.
“As the number of MDCT scans continues to grow in Australia at approximately 9 percent per year and the estimated per capita dose to the Australian population from MDCT is 1.2 mSv per year, any dose-saving strategy should provide substantial benefit from a public health perspective,” the authors offered.
“Our study showed that audit feedback and academic detailing in a small-group setting could achieve clinically important dose reductions in volunteer practices,” wrote Wallace and colleagues. Noting the “highly variable” nature of support provided by vendors and other personnel, “hands-on training of professionals at the practice level is an urgent need,” the study concluded.