Baldock C, Burford R P, Billingham N, Wagner G S, Patval S, Badawi R D, Keevil S F
Centre for Medical and Health Physics, Queensland University of Technology, Brisbane, Australia.
Phys Med Biol. 1998 Mar;43(3):695-702. doi: 10.1088/0031-9155/43/3/019.
A simple methodology for the manufacture and calibration of polyacrylamide gel (PAG) for magnetic resonance imaging (MRI) radiation dosimetry is presented to enable individuals to undertake such work in a routine clinical environment. Samples of PAG were irradiated using a linear accelerator and imaged using a 0.5 T (22 MHz) Philips Gyroscan MRI scanner. The mean spin-lattice relaxation rate was measured using a 'turbo-mixed' sequence, consisting of a series of 90 degrees pulses, each followed by acquisition of a train of spin echoes. The mean sensitivity for five different batches of PAG in the range up to 10 Gy was calculated to be 0.0285 s-1 Gy-1 for the mean spin-lattice relaxation rate with a percentage standard deviation of 1.25%. The overall reproducibility between batches was calculated to be 2.69%. This methodology, which introduces the novel use of pre-filled nitrogen vials for calibration, has been used to develop techniques for filling anatomically shaped anthropomorphic phantoms.
本文介绍了一种用于制造和校准用于磁共振成像（MRI）辐射剂量测定的聚丙烯酰胺凝胶（PAG）的简单方法，以使个人能够在常规临床环境中开展此类工作。使用直线加速器对PAG样品进行辐照，并使用0.5 T（22 MHz）飞利浦Gyroscan MRI扫描仪进行成像。使用“快速混合”序列测量平均自旋晶格弛豫率，该序列由一系列90度脉冲组成，每个脉冲之后采集一串自旋回波。对于平均自旋晶格弛豫率，计算得出在高达10 Gy范围内的五批不同PAG的平均灵敏度为0.0285 s-1 Gy-1，标准偏差百分比为1.25%。批次间的总体重现性计算为2.69%。这种引入预充氮瓶用于校准的新用途的方法，已被用于开发填充解剖形状人体模型的技术。
