Dose Enhancement for the Flattening-Filter-Free and Flattening-Filter Photon Beams in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Study
Dose Enhancement for the Flattening-Filter-Free and Flattening-Filter Photon Beams in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Study
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DOI：
10.3390/nano10040637
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发表时间：
2020-04-01
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：
Martelli, Stefano;Chow, James C. L.
采用蒙特卡罗模拟方法，结合纳米粒子材料、纳米粒子浓度、前列腺大小、盆腔大小和光子束能量等多个变量，对无滤光片(FFF)和滤光片(FF)光子束在前列腺纳米粒子增强放射治疗中的剂量增强率(DER)进行了预测。使用了一个模仿患者骨盆的体模，其前列腺和骨盆大小各不相同。使用EGSnrc代码的宏观蒙特卡罗模拟被用来预测前列腺或目标处的剂量，使用由瓦里安TrueBeam直线加速器(美国加州帕洛阿尔托的瓦里安医疗系统)产生的6 mV FFF、6 mV FF、10 mV FFF和10 mV FF光子束。在模拟中使用了金、铂、碘、银和氧化铁的纳米颗粒材料，其浓度在3-40 mg/ml范围内变化。前列腺大小2.5~5.5 cm，盆腔大小20~30 cm。在模拟中，DER被定义为添加纳米粒子的目标剂量与不添加纳米粒子的目标剂量的比率。从DER的蒙特卡罗结果来看，根据所有纳米粒子的浓度和光子束，具有最高DER的最佳纳米粒子材料是金。较小的前列腺大小、较小的盆腔大小和较高的纳米颗粒浓度显示出更好的结果。在能量比较时，6 mV光束的增强率始终较大。此外，与FF光相比，FFF光的光束总是有更好的性能。因此，金纳米粒子是纳米粒子增强放射治疗中最有效的材料。此外，较低的光子束能量(6 MV)、FFF光子束、较高的纳米粒子浓度、较小的盆腔大小和较小的前列腺大小都会增加前列腺纳米粒子增强放射治疗的DER。
Monte Carlo simulations were used to predict the dose enhancement ratio (DER) using the flattening-filter-free (FFF) and flattening-filter (FF) photon beams in prostate nanoparticle-enhanced radiotherapy, with multiple variables such as nanoparticle material, nanoparticle concentration, prostate size, pelvic size, and photon beam energy. A phantom mimicking the patient's pelvis with various prostate and pelvic sizes was used. Macroscopic Monte Carlo simulation using the EGSnrc code was used to predict the dose at the prostate or target using the 6 MV FFF, 6 MV FF, 10 MV FFF, and 10 MV FF photon beams produced by a Varian TrueBeam linear accelerator (Varian Medical System, Palo Alto, CA, USA). Nanoparticle materials of gold, platinum, iodine, silver, and iron oxide with concentration varying in the range of 3-40 mg/ml were used in simulations. Moreover, the prostate and pelvic size were varied from 2.5 to 5.5 cm and 20 to 30 cm, respectively. The DER was defined as the ratio of the target dose with nanoparticle addition to the target dose without nanoparticle addition in the simulation. From the Monte Carlo results of DER, the best nanoparticle material with the highest DER was gold, based on all the nanoparticle concentrations and photon beams. Smaller prostate size, smaller pelvic size, and a higher nanoparticle concentration showed better DER results. When comparing energies, the 6 MV beams always had the greater enhancement ratio. In addition, the FFF photon beams always had a better DER when compared to the FF beams. It is concluded that gold nanoparticles were the most effective material in nanoparticle-enhanced radiotherapy. Moreover, lower photon beam energy (6 MV), FFF photon beam, higher nanoparticle concentration, smaller pelvic size, and smaller prostate size would all increase the DER in prostate nanoparticle-enhanced radiotherapy.