The Application of Low-Dose MSCT on Pediatric Chest

Objective To evaluate the application of the low-dose in the pediatric chest multi-slice spiral CT(MSCT) examination.Methods Phantom measurement:the phantom scans were performed on the same location using doses 150,80,50,35,15mAs,and five same regions of interest were measured on every image.The homogeneity and noise level of CT were appraised.The patients’ scans:40 children with lung infection were selected randomly,conventional-dose (150mAs) MSCT examinations were performed to detect the lesion and then the low-dose (50,35 and 15mAs) scans were performed on the focus.Their weighted CT dose index(CTDIw) and dose lenth product(DLP) were compared.The image quality was graded as excellent,good,acceptable and unacceptable by two experienced radiologists.Results The phantom measurement suggested that the lower the dose,the lower the homogeneity was.The lower the dose,the higher the noise level was. CTDIw was 10.0mGy,3.3 mGy,2.3 mGy and 1.0 mGy,respectively,using 150 mAs,50 mAs,35 mAs and 15 mAs scanning protocol.Their DLPs was 117.8,39.3,27.5 and 11.8, respectively.90% of image quality was acceptable on both lung and mediastinum windows acquired using doses of 150 mAs,50 mAs,35 mAs,while image quality was unacceptable on the mediastinum window when acquired using 15mAs.Conclusion It is recommended that the dose of 35 mAs is applicable for pediatric chest study without image quality compromises.