Influence of Scan Field of View on Operator Radiation Exposure in Computed Tomography Fluoroscopy

Purpose: This study aimed to evaluate the effect of the scan field of view on operator radiation exposure during computed tomography fluoroscopy in computed tomography-guided interventional radiology procedures. Material and Methods: Two cylindrical phantoms (diameters: 220 mm and 330 mm) were scanned, and the tube currents were adjusted to achieve equivalent standard deviation values for scan field of view M (320 mm) and scan field of view L (500 mm), where standard deviation refers to the standard deviation of computed tomography attenuation values measured within a centrally placed square region of interest in the phantom image (expressed in Hounsfield units). Equivalent doses at the operator's position were measured under these standard deviation-equivalent conditions. Results: The results showed that the equivalent doses at the operator's position were significantly lower when using scan field of view M. The difference in radiation exposure was more pronounced with the larger phantom and increased by up to 15% when using the larger scan field of view (L), with scan field of view M as the reference. Conclusions: These findings suggest that using a smaller scan field of view can effectively reduce radiation exposure to the operator when a wide field of view is unnecessary for computed tomography fluoroscopy.