Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA.
Phys Med Biol. 2012 May 7;57(9):2575-86. doi: 10.1088/0031-9155/57/9/2575. Epub 2012 Apr 11.
In this work, the suitability and performance of a mouse-size MOSFET (Mousefet) phantom is investigated for routine quality assurance (QA) of the small animal radiation research platform (SARRP). This Mousefet phantom is a simple construction consisting of five micro-MOSFETS custom integrated in a quincunx pattern within a tissue-equivalent phantom, allowing repeat/multiple QA tasks to be quickly performed in one experimental set-up. The Mousefet phantom is particularly evaluated for facilitating SARRP QA tasks which may warrant daily evaluation, including output constancy, isocenter congruency test and cone beam computed tomography (CBCT) image geometric accuracy. Results for the output constancy measurements showed a maximum daily variation of less than 2.6% for all MOSFETS, in consonance with observations from concurrent ion chamber measurements. It is also shown that the design of the Mousefet phantom allows the output check data to be used for prompt verification of beam energy and cone profile constancy. For the isocenter congruency test, it is demonstrated that the Mousefet phantom can detect 0.3 mm deviations of the CBCT isocenter from the radiation isocenter. Meanwhile, results for CBCT image geometric accuracy were consistently found to be within 2% of the expected value. Other CBCT image quality parameters could also be assessed in terms of image intensity constancy, noise and image uniformity. Overall, the results establish the Mousefet phantom as a simple and time-efficient multipurpose tool that could be employed effectively for routine QA of the SARRP.
在这项工作中，研究了一种鼠标大小的 MOSFET（Mousefet）体模，以用于小型动物辐射研究平台（SARRP）的常规质量保证（QA）。这种 Mousefet 体模结构简单，由五个微 MOSFET 定制集成在组织等效体模中的五角星形图案中，允许在一个实验设置中快速执行重复/多次 QA 任务。Mousefet 体模特别适用于需要日常评估的 SARRP QA 任务，包括输出稳定性、等中心一致性测试和锥形束 CT（CBCT）图像几何精度。输出稳定性测量的结果表明，所有 MOSFET 的最大日变化都小于 2.6%，与同时进行的离子室测量的观察结果一致。还表明，Mousefet 体模的设计允许使用输出检查数据来快速验证束能和锥形束轮廓的稳定性。对于等中心一致性测试，证明 Mousefet 体模可以检测到 CBCT 等中心与辐射等中心之间 0.3 毫米的偏差。同时，CBCT 图像几何精度的结果始终在预期值的 2%以内。还可以根据图像强度稳定性、噪声和图像均匀性等方面评估其他 CBCT 图像质量参数。总体而言，结果表明 Mousefet 体模是一种简单且高效的多用途工具，可以有效地用于 SARRP 的常规 QA。
