Čerenkov radiation emission and excited luminescence (CREL) sensitivity during external beam radiation therapy: Monte Carlo and tissue oxygenation phantom studies.
Čerenkov radiation emission and excited luminescence (CREL) sensitivity during external beam radiation therapy: Monte Carlo and tissue oxygenation phantom studies.
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DOI：
10.1364/boe.3.002381
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发表时间：
2012-10-01
影响因子：
3.4
通讯作者：
Pogue BW
中科院分区：
文献类型：
--
作者：
Zhang R;Glaser A;Esipova TV;Kanick SC;Davis SC;Vinogradov S;Gladstone D;Pogue BW
放射治疗在组织中产生Čerenkov辐射发射，并且发射光谱中出现的光谱吸收特征可以用于根据已知的血红蛋白吸收来量化血氧饱和度（StO 2）。此外，Čerenkov光可用于激发探针PtG 4的氧敏感磷光，其发射寿命直接报告组织氧分压（pO 2）。因此，使用外部放射治疗束探测血红蛋白StO 2和pO 2两者以在肿瘤组织中创建作为内部光源是可行的。在这项研究中，这两个信号的灵敏度和空间起源进行了检查。发射检测使用光纤耦合增强器选通CCD相机接口的光谱仪。磷光寿命进行了量化，并与以前测量的StO 2的变化进行比较。线性加速器射束的蒙特卡罗模拟与光学信号的跟踪一起用于预测体模内的空间分布和区域灵敏度。当光纤到射束距离（FBD）从0到30 mm变化时，即从光纤尖端到放射治疗射束的最近侧的距离，对于600-1000 nm范围内的波长，CR发射的有效采样深度从4 mm变化到29 mm。对于二次发射（磷光）的有效采样深度被确定为在9至19 mm的范围内。这些结果表明，采样的StO 2和pO 2在组织中的放射治疗过程中应该是可行的，并且可以设置的辐射束和光纤采样几何形状，以获取信号，起源于深至几厘米的组织。
Radiotherapy generates Čerenkov radiation emission in tissue, and spectral absorption features appearing in the emission spectrum can be used to quantify blood oxygen saturation (StO2) from the known absorptions of hemoglobin. Additionally, the Čerenkov light can be used to excite oxygen-sensitive phosphorescence of probe PtG4, whose emission lifetime directly reports on tissue oxygen partial pressure (pO2). Thus, it is feasible to probe both hemoglobin StO2 and pO2 using external radiation therapy beam to create as an internal light source in tumor tissue. In this study, the sensitivity and spatial origins of these two signals were examined. Emission was detected using a fiber-optic coupled intensifier-gated CCD camera interfaced to a spectrometer. The phosphorescence lifetimes were quantified and compared with StO2 changes previously measured. Monte Carlo simulations of the linear accelerator beam were used together with tracking of the optical signals, to predict the spatial distribution and zone sensitivity within the phantom. As the fiber-to-beam distance (FBD) varied from 0 to 30 mm, i.e. the distance from the fiber tip to the nearest side of the radiotherapy beam, the effective sampling depth for CR emission changed from 4 to 29 mm for the wavelengths in the range of 600-1000 nm. For the secondary emission (phosphorescence) the effective sampling depth was determined to be in the range of 9 to 19 mm. These results indicate that sampling of StO2 and pO2 in tissue should be feasible during radiation therapy, and that the radiation beam and fiber sampling geometry can be set up to acquire signals that originate as deep as a few centimeters in the tissue.