Characterisation of a CZT detector for dosimetry of molecular radiotherapy
Characterisation of a CZT detector for dosimetry of molecular radiotherapy
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DOI：
10.1088/1748-0221/12/03/p03001
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发表时间：
2017-03-01
影响因子：
1.3
通讯作者：
Carroll, M.
中科院分区：
文献类型：
--
作者：
McAreavey, L. H.;Harkness-Brennan, L. J.;Carroll, M.
像素化镉碲化锌（CZT）探测器的特点是为了开发定量的单光子发射计算机断层扫描（SPECT）系统用于分子放射治疗（MRT）剂量测定。这就是CZT（描绘）剂量成像项目的目标，该项目是利物浦大学、皇家马斯登医院、皇家利物浦和布罗德格林大学医院以及商业合作伙伴Kromek之间的合作。CZT是一种直接带隙半导体，与当前SPECT系统中使用的闪烁体探测器相比，具有优越的能量分辨率和停止功率。研究了探测器的固有特性，并选择了偏置电压和峰值时间等工作参数来优化系统的性能。良好的能量分辨率需要区分从身体和准直器内发射的散射伽马射线，由于在MRT中管理的同位素的高活性，高光子吞吐量是必不可少的。该系统的平均测量电子噪声为3.31 keV，全宽半最大（FWHM），通过使用内部脉冲发生器确定。系统的能量响应在59.5 keV到364.5 keV的能量范围内被测量，发现是线性的。产生最佳FWHM和最大光子吞吐量的反向偏置电压和峰值时间分别为600 V和0.5 μ s。系统的平均死区时间为4.84 μ s，在59.5 keV下电荷分担率为0.71%。通过将该装置与原型准直器耦合，建立了像素灵敏度校准图，并获得了医学成像同位素Tc-99m和I-123的平面图像，从而证明了该探测器适合于描述项目。
Apixelated cadmium zinc telluride (CZT) detector has been characterised for the purpose of developing a quantitative single photon emission computed tomography (SPECT) system for dosimetry of molecular radiotherapy (MRT). This is the aim of the Dosimetric Imaging with CZT (DEPICT) project, which is a collaboration between theUniversity of Liverpool, The Royal Marsden Hospital, The Royal Liverpool and Broadgreen University Hospital, and the commercial partner Kromek. CZT is a direct band gap semiconductor with superior energy resolution and stopping power compared to scintillator detectors used in current SPECT systems. The inherent detector properties have been investigated and operational parameters such as bias voltage and peaking time have been selected to optimise the performance of the system. Good energy resolution is required to discriminate gamma-rays that are scattered as they are emitted from the body and within the collimator, and high photon throughput is essential due to the high activities of isotopes administered in MRT. The system has an average measured electronic noise of 3.31 keV full width at half maximum (FWHM), determined through the use of an internal pulser. The energy response of the system was measured across the energy region of interest 59.5 keV to 364.5 keV and found to be linear. The reverse bias voltage and peaking time producing the optimum FWHM and maximum photon throughput were 600 V and 0.5 mu s respectively. The average dead time of the system was measured as 4.84 mu s and charge sharing was quantified to be 0.71% at 59.5 keV. A pixel sensitivity calibration map was created and planar images of the medical imaging isotopes Tc-99m and I-123 were acquired by coupling the device to a prototype collimator, thereby demonstrating the suitability of the detector for the DEPICT project.