儿童人工耳蜗植入术作CT扫描时眼球的放射防护

Radiation protection for the eyes of the children experiencing an operation of artificial cochlear implant against CT scan

目的优化儿童人工耳蜗植入术前、后作颞骨CT扫描的曝光参数，减少其辐射危害。方法对疑有颞骨内耳病变者87例（其中人工耳蜗植入手术接受者31例），行颞骨薄层高分辨CT扫描（HRCT），以成人扫描参数为标准，适当调整扫描曝光量及扫描角度，直至图像符合诊断的要求，并分析其曝光量及单次扫描的加权CT剂量指数（CTDIw）和剂量长度乘积（DLP）。结果儿童颞骨CT扫描曝光量及单次扫描的CTDIw值可降低到成人曝光量的66．67％～83．33％，DLP也可降低到66．67％～83．33％，且内耳及植入电极三维重建图像质量优良。结论儿童人工耳蜗植入术前、术后作CT扫描曝光量的适当降低，以及扫描角度的适当调整，可有效地降低颞骨局部的辐射剂量，且有效地避免了儿童眼晶体的直接辐射伤害。

Objective To optimize the CT scanning parameters in pediatric temporal bone examination with artificial cochlear implant and reduce its radiation hazards. Methods The temporal bones of 87 patients with suspected inner ear disease which include 31 experienced artificial cochlear implant were scanned by HRCT. Regarding adult scan parameters as a criteria, properly adjusted the scanning dose and scanning angle until the quality of CT images was beyond the diagnosis demands. Finally the exposed doses, single scanning CT dose index weighted （CTDIw） and dose length product （DLP） were analysed. Results Compared with adult temporal bone scanning, the exposure value and CTDI, were reduced to 66.67%-83.33% , DLP of temporal bone scanning in pediatrics was reduced to 66.67%-83.33%, moreover, the imaging quality of tridimensional reconstruction for inner ear and implant electrode was improved. Conclusion The proper reduction of CT scan exposure on preoperative and postoperative children with cochlear implants and the proper adjustment of scan angle ean significantly reduce the exposure dose to local temporal bone and effectually avoid the damage to lens of children.