X-ray acoustic computed tomography with pulsed x-ray beam from a medical linear accelerator
X-ray acoustic computed tomography with pulsed x-ray beam from a medical linear accelerator
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DOI：
10.1118/1.4771935
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发表时间：
2013-01-01
期刊：
影响因子：
3.8
通讯作者：
Xing, Lei
中科院分区：
文献类型：
--
作者：
Xiang, Liangzhong;Han, Bin;Xing, Lei
目的：研究医用直线加速器产生声波用于医学成像的可行性。这种模式，X射线声学计算机断层扫描（XACT），有可能使更深的组织穿透组织比光声断层扫描通过laser excitation.Methods：短脉冲（亩范围）10 MV的X射线束的剂量率约为30戈伊/min的医用直线加速器产生。声信号用定位在物体周围的超声换能器（500 KHz中心频率）收集。由计算机控制的步进电机驱动的换能器围绕对象进行扫描，在每个扫描位置处检测成像平面中的所得声信号。一个脉冲放大器，带宽为20 KHz-2 MHz，-3 dB，可切换增益为40和60 dB，接收来自换能器的信号，并将放大的信号传送到二级放大器。次级放大器的带宽为20 KHz-30 MHz，-3 dB，增益范围为10 - 60 dB。记录信号并通过示波器平均128次。使用100 MHz的采样率在每个视角记录2500个数据点。当接收器移动360度时，一组数据包含200个位置。然后用滤波反投影算法重建X射线产生的声学图像。结果：从嵌入鸡胸组织中的铅杆检测到X射线产生的声学信号。作者发现，声信号与X射线剂量沉积成正比，相关性为0.998。铅棒嵌入鸡胸组织的二维XACT图像被发现是在良好的协议与形状的object.Conclusions：第一个X射线声学计算机断层扫描图像。新的模态可以用于许多应用，例如提供基准的位置，或在放射治疗期间监测X射线剂量分布。虽然需要做很多工作来提高XACT的图像质量，并探索其在其他照射能量下的性能，但正如本工作中所强调的那样，这种模式的好处鼓励进一步研究。(C)2013年美国医学物理学家协会。[http：//dx.doi.org/10.1118/1.4771935]
Purpose: The feasibility of medical imaging using a medical linear accelerator to generate acoustic waves is investigated. This modality, x-ray acoustic computed tomography (XACT), has the potential to enable deeper tissue penetration in tissue than photoacoustic tomography via laser excitation.Methods: Short pulsed (mu s-range) 10 MV x-ray beams with dose-rate of approximately 30 Gy/min were generated from a medical linear accelerator. The acoustic signals were collected with an ultrasound transducer (500 KHz central frequency) positioned around an object. The transducer, driven by a computer-controlled step motor to scan around the object, detected the resulting acoustic signals in the imaging plane at each scanning position. A pulse preamplifier, with a bandwidth of 20 KHz-2 MHz at -3 dB, and switchable gains of 40 and 60 dB, received the signals from the transducer and delivered the amplified signals to a secondary amplifier. The secondary amplifier had bandwidth of 20 KHz-30 MHz at -3 dB, and a gain range of 10-60 dB. Signals were recorded and averaged 128 times by an oscilloscope. A sampling rate of 100 MHz was used to record 2500 data points at each view angle. One set of data incorporated 200 positions as the receiver moved 360 degrees. The x-ray generated acoustic image was then reconstructed with the filtered back projection algorithm.Results: The x-ray generated acoustic signals were detected from a lead rod embedded in a chicken breast tissue. The authors found that the acoustic signal was proportional to the x-ray dose deposition, with a correlation of 0.998. The two-dimensional XACT images of the lead rod embedded in chicken breast tissue were found to be in good agreement with the shape of the object.Conclusions: The first x-ray acoustic computed tomography image is presented. The new modality may be useful for a number of applications, such as providing the location of a fiducial, or monitoring x-ray dose distribution during radiation therapy. Although much work is needed to improve the image quality of XACT and to explore its performance in other irradiation energies, the benefits of this modality, as highlighted in this work, encourage further study. (C) 2013 American Association of Physicists in Medicine. [http://dx.doi.org/10.1118/1.4771935]