A high-speed scintillation-based electronic portal imaging device to quantitatively characterize IMRT delivery.
A high-speed scintillation-based electronic portal imaging device to quantitatively characterize IMRT delivery.
复制标题
一种基于高速闪烁的电子射野成像设备，用于定量表征 IMRT 传输。
DOI：
10.1118/1.2143142
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发表时间：
2006
期刊：
影响因子：
3.8
通讯作者：
Dempsey,JamesF
中科院分区：
文献类型：
--
作者：
Ranade,ManishaK;Lynch,BartD;Li,JonathanG;Dempsey,JamesF
我们开发了一种采用快速闪烁体和高速相机的电子射野成像设备（EPID）。该器械设计用于准确、独立地表征在采用步进式或动态多叶准直器（MLC）输送的调强放射治疗（IMRT）期间直线加速器输送的通量。我们的目标是准确地获得在调强放射治疗过程中提供的所有节段的射束形状和注量，以研究计划和提供的剂量之间的差异的性质。将商用高速摄像机与掺铽氧硫化钆闪烁体组合，以形成EPID，用于在IMRT输送中无混叠捕获每个射束的二维注量分布。高速EPID与加速器脉冲形成网络同步，并被选通以捕获从加速器发射的每个可能的脉冲，其帧速率大约为（fps）。使用我们的高速EPID记录了需要输送的头颈部IMRT治疗计划的62段射束，产生了大约的成像数据。将EPID数据与MLC指令文件和MLC控制器日志文件进行比较。对帧进行分箱，以提供具有足以分辨叶位置和节段通量的信噪比的帧速率。来自日志文件和EPID数据的分数通量一致。解决了在射束开启期间MLC运动的模糊性。日志文件在42个片段中的33个片段的末端报告了叶运动，而EPID仅在42个片段中的7个片段中观察到叶运动。高速EPID观察到的静态IMRT段形状与日志文件中报告的形状一致。日志文件未在时间上解决步进式输送的射束开启期间观察到的叶片运动。
We have developed an electronic portal imaging device (EPID) employing a fast scintillator and a high‐speed camera. The device is designed to accurately and independently characterize the fluence delivered by a linear accelerator during intensity modulated radiation therapy (IMRT) with either step‐and‐shoot or dynamic multileaf collimator (MLC) delivery. Our aim is to accurately obtain the beam shape and fluence of all segments delivered during IMRT, in order to study the nature of discrepancies between the plan and the delivered doses. A commercial high‐speed camera was combined with a terbium‐doped gadolinium‐oxy‐sulfide scintillator to form an EPID for the unaliased capture of two‐dimensional fluence distributions of each beam in an IMRT delivery. The high speed EPID was synchronized to the accelerator pulse‐forming network and gated to capture every possible pulse emitted from the accelerator, with an approximate frame rate of (fps). A 62‐segment beam from a head‐and‐neck IMRT treatment plan requiring to deliver was recorded with our high speed EPID producing approximately of imaging data. The EPID data were compared with the MLC instruction files and the MLC controller log files. The frames were binned to provide a frame rate of with a signal‐to‐noise ratio that was sufficient to resolve leaf positions and segment fluence. The fractional fluence from the log files and EPID data agreed well. An ambiguity in the motion of the MLC during beam on was resolved. The log files reported leaf motions at the end of 33 of the 42 segments, while the EPID observed leaf motions in only 7 of the 42 segments. The static IMRT segment shapes observed by the high speed EPID were in good agreement with the shapes reported in the log files. The leaf motions observed during beam‐on for step‐and‐shoot delivery were not temporally resolved by the log files.