First demonstration of real-time gamma imaging by using a handheld Compton camera for particle therapy
First demonstration of real-time gamma imaging by using a handheld Compton camera for particle therapy
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首次演示使用手持式康普顿相机进行粒子治疗的实时伽马成像
DOI：
10.1016/j.nima.2016.04.028
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
A.Kishimoto et al.
中科院分区：
文献类型：
--
作者：
T.Taya;J.Kataoka;A.Kishimoto et al.
在粒子治疗中使用实时伽马成像进行癌症治疗有望提高治疗射束输送的准确性。在这项研究中，我们演示了质子辐照过程中核相互作用产生的γ射线的成像，使用基于闪烁探测器的手持式康普顿相机（14 cm×15 cm×16 cm，2.5 kg）。该相机对~（137）Cs源的角分辨率为~（138）°。我们测量的γ射线的能谱使用溴化镧（铈）闪烁体和光电倍增管，并使用手持式康普顿相机，进行图像重建时，使用70 MeV的质子束照射水，Ca（OH）2，和聚甲基丙烯酸甲酯（PMMA）的幻影。在三个体模的能谱中，我们发现一个明显的峰位于511 keV，它来自湮没γ射线，而在PMMA体模的能谱中，我们发现另一个峰位于718 keV，它包含了10 B产生的瞬发γ射线。因此，我们评估了PMMA体模重建图像的投影峰值位置。使用模拟计算的峰值位置和布拉格峰值位置之间的差分别为7 mm±2 mm和3 mm±8 mm。虽然我们可以在质子辐照过程中快速获得两个能量范围的在线伽马成像，但由于康普顿相机的空间分辨率的不确定性，我们无法得出一个明确的结论，即即时伽马射线足以从这些结果中跟踪布拉格峰。我们将在不久的将来开发一台高分辨率的康普顿相机，以供进一步研究。
The use of real-time gamma imaging for cancer treatment in particle therapy is expected to improve the accuracy of the treatment beam delivery. In this study, we demonstrated the imaging of gamma rays generated by the nuclear interactions during proton irradiation, using a handheld Compton camera (14 cm×15 cm×16 cm, 2.5 kg) based on scintillation detectors. The angular resolution of this Compton camera is ∼8° at full width at half maximum (FWHM) for a137Cs source. We measured the energy spectra of the gamma rays using a LaBr3(Ce) scintillator and photomultiplier tube, and using the handheld Compton camera, performed image reconstruction when using a 70 MeV proton beam to irradiate a water, Ca(OH)2, and polymethyl methacrylate (PMMA) phantom. In the energy spectra of all three phantoms, we found an obvious peak at 511 keV, which was derived from annihilation gamma rays, and in the energy spectrum of the PMMA phantom, we found another peak at 718 keV, which contains some of the prompt gamma rays produced from10B. Therefore, we evaluated the peak positions of the projection from the reconstructed images of the PMMA phantom. The differences between the peak positions and the Bragg peak position calculated using simulation are 7 mm±2 mm and 3 mm±8 mm, respectively. Although we could quickly acquire online gamma imaging of both of the energy ranges during proton irradiation, we cannot arrive at a clear conclusion that prompt gamma rays sufficiently trace the Bragg peak from these results because of the uncertainty given by the spatial resolution of the Compton camera. We will develop a high-resolution Compton camera in the near future for further study.