Feasibility of reduced-dose CT of the head and neck with iterative reconstruction: a phantom and prospective clinical study

Abstract

Background: There is growing concern over computed tomography (CT)-related radiation exposure, particularly in patients requiring head and neck CT due to the proximity of radiosensitive organs. Purpose: We aimed to evaluate the feasibility of reduced-dose CT of the head and neck with iterative reconstruction in a phantom and patient study. Material and Methods: In the phantom study, low-contrast resolution test of the American Association of Physicists in Medicine CT performance phantom was scanned to determine the lowest acceptable tube current (mAs). In the patient study, three sets of CT images (standard-dose [200 mAs] and reduced-dose with iterative reconstruction or filtered back projection [FBP]) were prospectively obtained. The image noise, qualitative image quality, and radiation dose were compared. Results: In the phantom study, 100 mAs was determined as the lowest acceptable value. In the patient study (n = 29), reduced-dose CT with FBP showed significantly higher image noise and lower qualitative image quality than reduced-dose CT with iterative reconstruction and standard-dose CT (P < 0.05). There was no significant difference in image noise and qualitative image quality between reduced-dose CT with iterative reconstruction and standard-dose CT (P > 0.05). The radiation dose of the reduced-dose CT was significantly lower than that of the standard-dose CT (volume CT dose index = 6.9 vs. 14.3, P < 0.001; dose-length product = 223.6 vs. 455.8, P < 0.001). Conclusions: Reduced-dose CT with iterative reconstruction is a potential alternative to standard-dose CT of the head and neck, reducing radiation dose by approximately 50% while preserving image quality. © The Foundation Acta Radiologica 2019.