Significant dose reduction in diagnostic cerebral angiography using the ALARA principle and state-of-the-art medical equipment

Operator experience, the use of low frame rates during both fluoroscopy and DSA, and the application of modern medical equipment are crucial for ensuring optimal image quality while maintaining minimal exposure to ionising radiation during cerebral angiography. Our centre achieves this by using the lowest possible fluoroscopy frame rate (3.125 frames per second), a the operator set the nominal acquisition parameters at 2 fps for digital subtraction angiography (DSA), three-dimensional (3D) rotational angiography, two-dimensional /3D mapping, and roadmapping, without compromising the quality of the images obtained. A total of 213 diagnostic procedures for intracranial aneurysms, performed at a single medical centre between 2018 and 2024, were analyzed. Key exposure parameters were collected and analyzed for each procedure, including dose area product (DAP), air kerma (Ka,r), fluoroscopy time (FT), and the total number of DSA frames. The local diagnostic reference level (DRL) and typical values for cerebral angiography were determined and compared with data available in the relevant literature. The 75th percentile (P75) values, assumed to be the DRL, were 23.57 Gy · cm²for DAP (literature range: 90-209), 153 mGy for Ka,r (literature range: 711.3-1401 mGy), 10 min and 46 s for FT, and 257 for the number of DSA frames during diagnostic procedures. Typical values (50th percentile [P50]) were 13.4 Gy · cm²for DAP (literature range: 43.1-157), 92 mGy for Ka,r (literature range: 312-598 mGy), six minutes and 20 s for FT, and 182 for the number of DSA frames during diagnostic procedures. The P50 dose DRLs, measured via DAP, Ka,r, FT, and the number of DSA frames, were at least three times lower at our facility than those reported in studies on cerebral angiography published between 2013 and 2023. The use of low frame rates during both fluoroscopy and DSA has a significant impact on the radiation dose measured by DAP, Ka,r, FT, and the number of DSA frames. The proposed DRLs could be used to ensure quality and patient safety in diagnostic procedures.