| Summary: | 碩士 === 中臺科技大學 === 醫學影像暨放射科學系暨研究所 === 105 === Hybrid iterative reconstruction (iDose4) is introduced as a computed tomography (CT) image reconstruction technique by Philips Healthcare. The aim of this study was to evaluate the image quality by using Chest Phantom with iDose4.
A phantom (multipurpose Chest Phantom N1 “LUNGMAN”) was performed by using parameters of adult chest CT, the protocol of 120 kVp and 180 mAs. For dose reduction, the kVp remained the same, and the mAs was reduced by 40 mAs each time, up to 20 mAs. All image data was reconstructed by FBP and iDose4 level 1-6 to calculate the signal to noise ratio (SNR) , peak signal to noise ratio (PSNR) and root means square error (RMSE) for image quality evaluation.
The CTDIvol was showed 14.4, 11.8, 9.2, 6.5, 3.9 and 1.3 mGy for each scanning protocol. Noise reduction compared with FBP and each iDose4 level 1-6 were 12 %, 18 %, 25 %, 32 %, 38 % and 47 %, respectively.
The data slowed that the chest CT image quality can be improved at standard protocol and controlled mAs by using iDose4, and the maximum dose reduction was up to 67 %. RMSE and PSNR showed that Level 5 and Level 6 have less image noise, better image quality and smaller different between original and reconstruction image.
|
|---|
