Three-Dimensional Radiation Dosimetry Using MRI-Fricke-Agarose Gel Technique

• Main Authors: C. H. Tsai, 蔡志豪
• Other Authors: W. C. Chu
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/58414167849594931355

碩士 === 國立陽明大學 === 醫學工程研究所 === 87 === Traditionally one can use TLD, ion chamber or radiographic film to measure absorbed radiation dose. But it is impossible to use these methods to measure dose in the human body directly. Instead, we use Fricke-Agarose gel phantom to simulate human body, and by MR imaging the gel phantom, we are able to obtain dose distribution information. The effects of ferric ion diffusion in Fricke-Agarose gel dosimetry requires that MR images to be acquired in as short time as possible. We compare the conventional R1（T1 relaxation rate） mapping technique and image intensity mapping technique for dose measurement accuracy. Results show that intensity mapping method out performs the R1 method in the Fricke-Agarose gel dosimetry. Besides gamma knife radiosurgery, it may be applied to other three-dimensional radiation dosimetry.