Radiation doses, noise properties, and in-plane spatial resolutions for CT coronary angiography using different CT scanners: Phantom study

Abstract

Objective: We aimed to evaluate radiation doses, noise properties, and in-plane spatial resolutions for CT coronary angiography (CTCA) using different CT scanners and phantoms.

Methods: ECG-gated step-and-shoot (SAS) and low-pitch spiral (LPS) acquisitions were performed using the 64-section single-source CT (SSCT) system. ECG-gated high-pitch spiral (HPS), SAS, and LPS acquisitions were performed using the 128-section dual-source CT (DSCT) system. The absorbed doses for thoracic organs were measured using an anthropomorphic phantom and radiophotoluminescent glass dosimeters. Noise properties and in-plane spatial resolutions were evaluated using a calibration phantom and a cylinder phantom constructed in-house, respectively.

Results: The absorbed doses for thoracic organs differed significantly depending on the acquisition modes and not the scanners. The doses absorbed by the heart were 66.8 and 215.5 mGy with SAS and LPS acquisitions using the 64-section SSCT system, respectively, and 10.0, 96.1, and 195.7 mGy with HPS, SAS, and LPS acquisitions using the 128-section DSCT system, respectively. Noise properties and in-plane spatial resolutions differed significantly depending on the scanners used but not the acquisition modes.

Conclusions: To optimize the patient dose, an appropriate acquisition mode should be chosen according to the scanner type, patient’s average heart rate, stability of a patient’s heartbeat, and patient’s history.