磁振造影技術與承載假體應用於聚合物凝膠劑之探討

Application of Loading Phantom for Magnetic Resonance Imaging in Polymer Gel Dosimetry

洪千惠(Chian-Huei Hung)

指導教授 ： 張振榮 ； 江志明

中臺科技大學/健康科學院/放射科學研究所/碩士(2011年)

摘要

聚合物凝膠劑量計對輻射偵測具有高靈敏度，經輻射照射後產生的聚合及交聯反應，對於輻射偵測具有高靈敏度。磁振造影 (magnetic resonance imaging, MRI) 是被公認最具潛力之凝膠劑量計讀出工具，以磁振造影測凝膠劑量計時，需要設計可同時支撐多跟詴管的承載假體作為支架，本研究主要針對圓盤狀 (氣體)、全固態 (壓克力) 及愛玉 (膠體) 三種設計之承載假體的劑量反應曲線進行比較，並探討凝膠劑量計在三種承載假體當中的MRI 影像品質，包括影像不均度 (nonuniformity) 及訊號雜訊比 (SNR) 為影像品質比較的指標。研究數據顯示愛玉承載假體影像均勻度最佳 (1.60 %~1.84 %) ，而全固態承載假體之SNR 最佳 (391~513)。另外以劑量間隔方法測詴MRI 儀器對於劑量變化偵測的鑑別程度 (scale=0.2 , 0.5, 1Gy)。MRI 儀器在0~1.6 Gy 劑量區可鑑別的最小劑量間隔為0.2 Gy，在12~16 Gy 劑量區可鑑別的最小劑量間隔則為0.5 Gy。本研究結果顯示承載假體提升凝膠劑量計於MRI 掃描的影像品質。

關鍵字

磁振造影 ； 凝膠劑量計 ； 承載假體

並列摘要

The sensitivity of polymer gel dosimeter is high in radiation detection, which will be polymerized or cross-linked under the radiation exposure. Magnetic Resonance Imaging (MRI) was recognized as the most potential device in measuring the radiation dosage by gel dosimeters. However, the image quality of MRI is highly affected by the materials of the loading phantom, which can carry the test tubes in position during MRI testing. Therefore, in this study, the disc-shaped prosthesis, whole solid phantom and Gd jelly phantom were compared in the dose-response curve, image nonuniformity and SNR in the standard imaging quality. The results demonstrated that the Gd jelly phantom and the whole solid phantom display higher imaging quality nonuniformity (1.60%~1.84 %) and higher SNR (391~513), respectively. In addition, the dose scale method (scale=0.2, 0.5 and 1Gy) was utilized to study the dose discrimination of MRI. The discrimination in the dose range of 0~1.6 Gy and 12~16 Gy were 0.2 Gy and 0.5 Gy, respectively. The results showed that the loading phantom could easily promote the MRI imaging quality of the Polymer gel dosimeter.

並列關鍵字

Loading phantom ； Polymer gel dosimeter ； Magnetic Resonance Imaging (MRI)

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