Proposal of a hybrid dosimetry method for improving work efficiency in CT dose management

In recent years in JAPAN, with the reform of work styles and the expansion of radiologists' duties, there has been a demand for more work improvement. Among them, many regulations surrounding computed tomography (CT) tasks require a large amount of time and manpower. In this study, we propose a hybrid method between leakage X-ray dosimetry and CT dose index (CTDI) measurement using a CTDI phantom used for CTDI measurement and elucidate the usefulness of the hybrid method. The results of the CTDI phantom generated more scattered radiation in the CT room; therefore, the previously used thoracoabdominal phantom could be replaced with the CTDI phantom. The number of exposures can be reduced by a factor of 15, work hours by 20 min, and the number of workers by two when evaluated as an average of four facilities using the hybrid method. The hybrid method enables the determination of the reproducibility of the output X-ray dose during leakage X-ray dosimetry, thereby ensuring the reliability of periodic leakage X-ray dosimetry. The use of the proposed hybrid method is reasonable because it is effective for work improvement, such as reducing work time and the number of workers.