Published online Oct 15, 2017. doi: 10.4251/wjgo.v9.i10.423
Peer-review started: May 17, 2017
First decision: July 11, 2017
Revised: July 25, 2017
Accepted: August 16, 2017
Article in press: August 17, 2017
Published online: October 15, 2017
To compare radiation dose and image quality of low-dose computed tomography (CT) protocol combined with hybrid-iterative reconstruction algorithm with standard-dose CT examinations for follow-up of oncologic patients.
Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standard-dose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated mA modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 mAs (depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise (SD), sharpness and diagnostic quality with 4-point scale.
Density values in liver, spleen and aorta were higher in low-dose images (liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen (liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index (CTDIvol) and Dose-Length-Product (DLP) were significantly lower in low-dose CT as compared to standard-dose (DLP 1025.6 mGy*cm vs 1429.2 mGy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality.
Automatic tube-current modulation combined with hybrid-iterative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.
Core tip: Introduction of new generation of multidetector computed tomography (MDCT) scanner allowed thin-collimation scanning and high spatial resolution, and reducing at same time the delivered radiation dose to patients by using new iterative reconstruction algorithm. This new mathematical model approach permits to reduce the radiation dose, expecially in patients who undergo serial follow-up study for oncologic (staging and restaging) purpose. On these basis in our study we evaluated radiation dose and image quality of CT examinations in a population of oncologic patients undergoing follow-up examinations with a new generation MDCT scanner (256-rows) using automatic modulation of tube current and iterative reconstruction algorithm (DoseRight system).