Contrast Enhancement for Portal Imaging in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Evaluation Using Flattening-Filter-Free Photon Beams
Contrast Enhancement for Portal Imaging in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Evaluation Using Flattening-Filter-Free Photon Beams
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DOI：
10.3390/nano9070920
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发表时间：
2019-07-01
期刊：
影响因子：
5.3
通讯作者：
Chow, James C. L.
中科院分区：
文献类型：
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作者：
Abdulle, Aniza;Chow, James C. L.
我们的团队在纳米粒子增强放射治疗中使用蒙特卡罗模拟评估了射野成像的对比度增强。通过改变纳米颗粒材料（金、铂、碘、银、氧化铁）、纳米颗粒浓度（3 - 40 mg/mL）和光子束能量（6和10 MV）来确定在双折射滤光片（FF）和无双折射滤光片（FFF）光子束上的对比度增强百分比的差异。基于Varian TrueBeam直线加速器生成6 MV FF、6 MV FFF、10 MV FF和10 MV FFF光子束的相空间文件和能谱。我们发现，金和铂纳米粒子（NP）产生最高的对比度增强门静脉成像相比，其他NP具有较低的原子序数。浓度等于40 mg/mL时，金和铂NP的最大对比度增强百分比分别为18.9%和18.5%。还发现对比度增强随着纳米颗粒浓度而增加。金NP的对比增强的最大增加率等于0.29%/mg/mL。使用6 MV光子束，金NP的最大对比度增强分别为79%（FF）和78%（FFF）高于使用10 MV光束的那些。对于FFF光束，金NP的最大对比度增强分别为53.6%（6 MV）和53.8%（10 MV），高于使用FF光束。结果表明，在纳米粒子增强放射治疗中，采用较高的NP原子序数、较高的纳米粒子浓度、较低的光子束能量和不使用光子束平坦滤波器，可以提高射野成像的对比度增强效果。
Our team evaluated contrast enhancement for portal imaging using Monte Carlo simulation in nanoparticle-enhanced radiotherapy. Dependencies of percentage contrast enhancement on flattening-filter (FF) and flattening-filter-free (FFF) photon beams were determined by varying the nanoparticle material (gold, platinum, iodine, silver, iron oxide), nanoparticle concentration (3-40 mg/mL) and photon beam energy (6 and 10 MV). Phase-space files and energy spectra of the 6 MV FF, 6 MV FFF, 10 MV FF and 10 MV FFF photon beams were generated based on a Varian TrueBeam linear accelerator. We found that gold and platinum nanoparticles (NP) produced the highest contrast enhancement for portal imaging, compared to other NP with lower atomic numbers. The maximum percentage contrast enhancements for the gold and platinum NP were 18.9% and 18.5% with a concentration equal to 40 mg/mL. The contrast enhancement was also found to increase with the nanoparticle concentration. The maximum rate of increase of contrast enhancement for the gold NP was equal to 0.29%/mg/mL. Using the 6 MV photon beams, the maximum contrast enhancements for the gold NP were 79% (FF) and 78% (FFF) higher than those using the 10 MV beams. For the FFF beams, the maximum contrast enhancements for the gold NP were 53.6% (6 MV) and 53.8% (10 MV) higher than those using the FF beams. It is concluded that contrast enhancement for portal imaging can be increased when a higher atomic number of NP, higher nanoparticle concentration, lower photon beam energy and no flattening filter of photon beam are used in nanoparticle-enhanced radiotherapy.