Purpose: In DRLs 2020, the entrance surface air kerma (Ka,e) was set to 17 mGy/min as the reference dose rate in fluoroscopy. But, Ka,e in fluoroscopy for different regions and Ka,e in exposure was not set. A multicenter survey was conducted to evaluate Ka,e by each area.
Methods: Ka,e for each area was analyzed for 79 facilities attending this survey (274 machines and 461 protocols). When the protocols were changed by the difference in disease, angiography, or IVR, the difference rate of Ka,e was evaluated. Ka,e before and after modifying the incident air kerma at the patient entrance reference point (Ka,r) and air kerma area product (PKA) difference rate were calculated when protocols were changed, considering the DRLs 2020.
Results: There were dose differences in Ka,e by each area. Compared to DRLs 2020, 36 protocols from 13 facilities modified their protocols, all of which reduced Ka,e.
Conclusion: Although reducing Ka,e does not necessarily reduce Ka,r, and PKA, comparison of Ka,e by each area is expected to optimize medical exposure protection, including evaluation of quality control.
Keywords: diagnostic reference level (DRL); entrance surface air kerma (Ka,e); interventional radiology (IVR).