Xie Yunhe, Bentefour El Hassane, Janssens Guillaume, Smeets Julien, Vander Stappen François, Hotoiu Lucian, Yin Lingshu, Dolney Derek, Avery Stephen, O'Grady Fionnbarr, Prieels Damien, McDonough James, Solberg Timothy D, Lustig Robert A, Lin Alexander, Teo Boon-Keng K
Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
Advanced Technology Group, Ion Beam Applications SA, Louvain-la-Neuve, Belgium.
Int J Radiat Oncol Biol Phys. 2017 Sep 1;99(1):210-218. doi: 10.1016/j.ijrobp.2017.04.027. Epub 2017 May 3.
To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode.
A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan.
In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field.
This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties.
报告在笔形束扫描模式下进行体内质子射程验证的即时伽马成像的首次临床结果和价值评估。
使用一台独立的、安装在手推车上的、采用刀口狭缝准直器设计的即时伽马相机原型，记录一名脑癌患者在质子治疗过程中沿质子轨迹发射的即时伽马信号。将记录的各个笔形束光斑的即时伽马深度检测轮廓与治疗计划模拟的预期轮廓进行比较。
在3周内记录的6个治疗分次中，9个能量层中所有光斑的平均（±标准差）射程偏移，侧野为-0.8±1.3毫米，右上斜野为1.7±0.7毫米，头顶野为-0.4±0.9毫米。
本研究证明了即时伽马成像在笔形束扫描治疗模式下的可行性，并说明了其独特优势。在这例首例临床病例中发现，射程验证的准确性优于治疗计划中应用的射程不确定度余量。这些初步结果为进一步开展工作奠定了基础，以更紧密地整合用于体内质子射程验证和射程不确定度量化的系统。
