1 College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
2 Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University, Changzhou, China.
Technol Cancer Res Treat. 2019 Jan 1;18:1533033819844485. doi: 10.1177/1533033819844485.
To study the effect of a metal tracheal stent on radiation dose distribution.
A metal tube bracket is placed in a self-made foam tube sleeve, and micro-computed tomography scanning is performed directly. The foam sleeve containing the metal bracket is placed in a nonuniform phantom for a routine computed tomography scan. The stents in conventional computed tomography images are replaced by the stents in micro-computed tomography images. Subsequently, 2 sets of computed tomography images are obtained and then imported to a radiotherapy treatment planning system. A single photon beam at 0° is designed in a field size of 10 cm × 10 cm, a photon beam of 6 MV, and a monitor unit of 200 MU. Monte Carlo algorithm is used to calculate the dose distribution and obtain the dose curve of the central axis of the field. The dose is verified with thermoluminescence dose tablets.
The micro-computed tomography images of the tracheal stent are clearer and less false-like than its conventional computed tomography images. The planned dose curves of the 2 groups are similar. In comparison with the images without any stents in place, the doses at the incident surface of the stent in the conventional computed tomography images and at the stent exit surface in the rear of the stent increase by 1.86% and 2.76%, respectively. In the micro-computed tomography images, the doses at the incident surface of the stent and at the exit surface behind the stent increase by 1.32% and 1.19%, respectively. Conventional computed tomography reveals a large deviation between the measured and calculated values.
Tracheal stent based on micro-computed tomography imaging has a less effect on radiotherapy calculation than that based on conventional computed tomography imaging.
研究金属气管支架对放射剂量分布的影响。
将金属管支架置于自制泡沫管套中，直接行微计算机断层扫描。将含有金属支架的泡沫套置于非均匀体模中进行常规计算机断层扫描。用微计算机断层扫描图像中的支架替换常规计算机断层扫描图像中的支架。随后，获取 2 套计算机断层扫描图像，并将其导入放射治疗计划系统。在野尺寸为 10cm×10cm、光子束为 6MV、监测单位为 200MU 的条件下，设计一个 0°单光子束。采用蒙特卡罗算法计算剂量分布，得到野中心轴的剂量曲线。使用热释光剂量计验证剂量。
气管支架的微计算机断层扫描图像比常规计算机断层扫描图像更清晰，伪影更少。2 组的计划剂量曲线相似。与无任何支架的图像相比，常规计算机断层扫描图像中支架入射面的剂量增加了 1.86%，支架后端出口面的剂量增加了 2.76%。在微计算机断层扫描图像中，支架入射面和支架后端出口面的剂量分别增加了 1.32%和 1.19%。常规计算机断层扫描显示出测量值和计算值之间的较大偏差。
基于微计算机断层扫描成像的气管支架对放射治疗计算的影响小于基于常规计算机断层扫描成像的支架。
