Abstract
Objective: Computed tomography (CT) is the standard imaging modality for the sinuses. Patients frequently undergo multiple scans from diagnosis to image-guided surgery, and incorrect scans necessitate repeat imaging. A protocol was established to reduce the number of scans obtained and to limit radiation exposure to our sinus patients.
Method: We designed a single isotropic study for diagnosis and surgical navigation. Reductions in kVp were made that would not compromise image detail or navigation fidelity. Two hundred adult CT sagittal sinus topograms were analyzed to determine how much cranial vertex could be eliminated from the imaged field.
Results: The total radiation dose during image capture was reduced from 120 to 100 kVp without an appreciable change in detail. Average distance from supraorbital rim to the cephalad aspect of the frontal sinus was 1.4 (0-3.5) cm, and from the cephalad aspect to the vertex was 6.8 (3.9-10) cm. It was conservatively calculated that 3.0 cm of vertex could be cropped without compromising the frontal sinuses and would permit successful placement of the navigation headset. These changes resulted in approximately 30% reduction in radiation exposure per scan. This standardized sinus CT replaced other options, reducing the need for repeat imaging.
Conclusion: Reducing dose, eliminating the vertex of the head, and offering only 1 multipurpose sinus CT results in significant reductions in radiation exposure without compromising diagnostic or navigational functionality. This new sinus CT protocol has been successfully implemented throughout our healthcare system.
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