Radiation exposure with 3D rotational angiography of the skull

Purpose: Determination and comparison of radiation exposure for examinations of the skull with unsubtracted 3D Rotational Angiography (3D RA) and 2D Digital Subtraction Angiography (2D DSA). Materials and Methods: Measurements were carried out with a skull of an Alderson phantom for 3D RA and for 2D DSA in p. a. and lateral projections using an Innova 4100 angiography system with a digital flat panel detector from GE Healthcare. 45 thermoluminescent dosimeters TLD 100H from Harshaw were placed inside the phantom to measure organ doses. In addition the dose area product was recorded and the effective dose was calculated using the Monte Carlo program PCXMC. Results: For a biplanar DSA run (lateral and p.a. projection), the organ doses were 4 to 5 times higher and the effective dose was 4 times higher than for a 3D RA even though the number of images for the two DSA runs was only half of that for 3D RA. Conclusion: The radiation exposure for unsubtracted 3D RA using a flat panel detector is significantly lower than for biplanar DSA. Using 3D RA in place of 2D DSA can reduce the radiation exposure of patients in neuroradiology procedures.