A novel method for megavoltage scatter correction in cone-beam CT acquired concurrent with rotational irradiation
A novel method for megavoltage scatter correction in cone-beam CT acquired concurrent with rotational irradiation
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DOI：
10.1016/j.radonc.2011.08.019
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发表时间：
2011-09-01
影响因子：
5.7
通讯作者：
Sonke, Jan-Jakob
中科院分区：
文献类型：
--
作者：
van Herk, Marcel;Ploeger, Lennert;Sonke, Jan-Jakob
背景和目的：与VMAT同时采集锥形束CT（CBCT）会导致兆伏（MV）射束散射到千伏（kV）探测器上，从而降低CBCT图像质量。本文的目的是开发一种方法来估计和校正MV散射到达kV panel.Material和methods：校正方法是基于一个交替的脉冲序列，这样的kV源是启用只有每隔一帧。KV未曝光帧中的MV散射、噪声和伪影基于它们的空间和时间频率特性被分离，并且随后从曝光帧中被减去。该方法进行了测试的幻影和一个肺癌患者扫描上的Elekta Synergy戈伊系统，同时与9戈伊VMAT delivery.Results：没有纠正，收购过程中VMAT导致显着的杯状和骨对比度的损失。该新方法消除了由于MV散射引起的信号。与没有MV射束的采集相比，除了由于暴露帧中散射的MV辐射而产生的一些不可避免的噪音之外，重建质量是相同的。校正进行在线采集，而不引入delays.Conclusions：开发了一种新的，高效和有效的方法，以纠正MV散射CBCT扫描同时获得旋转放疗。(C)2011爱思唯尔爱尔兰有限公司保留所有权利。放射治疗和肿瘤学100（2011）365-369
Background and purpose: Acquisition of cone-beam CT (CBCT) concurrent with VMAT results in scatter of the megavoltage (MV) beam onto the kilovoltage (kV) detector deteriorating CBCT image quality. The aim of this paper is to develop a method to estimate and correct for MV scatter reaching the kV panel.Material and methods: The correction method is based on an alternating pulse sequence such that the kV source is enabled in only every other frame. MV scatter, noise and artifacts ill the kV-unexposed frames are separated based on their spatial and temporal frequency characteristics and subsequently subtracted from the exposed frames. The method was tested on a phantom and one lung cancer patient scanned on an Elekta Synergy system simultaneous with a 9 Gy VMAT delivery.Results: Without correction, acquisition during VMAT leads to significant cupping and loss of bone contrast. The novel method removes the signal due to MV scatter. Compared to acquisition without MV beam, the reconstruction quality is identical except for some unavoidable noise due to the scattered MV radiation in the exposed frames. Correction is performed in-line with acquisition without introducing delays.Conclusions: A novel, efficient and effective method was developed to correct for MV scatter In CBCT scans acquired concurrent with rotational radiotherapy. (C) 2011 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 100 (2011) 365-369