Radiobiology Experimental and Monte Carlo Validation of Proton Capture Therapy of Low-Energy Proton Beams for SAS Cells
Abstract
Purpose
To increase the biological effectiveness of proton therapy, a novel approach proton boron/nitrogen capture therapy (PCT) were proposed. This research was carried out to evaluate the increased the radiobiological effectiveness of PCT with Monte Carlo and experiment.
Methods
The dose-averaged linear energy transfer (LETd) is a key physical parameter for evaluating the relative biological effectiveness (RBE) of proton therapy. The LETd of proton boron capture therapy (PBCT) and proton nitrogen capture therapy (PNCT) were calculated from Geant4and deep-learning-based models. To confirm MC work on PCT, here we report new in-vitro data obtained at the 3 MV tandetron accelerator (5 MeV proton beam) of the Sichuan University, Chengdu, China. We used 11B-Paraboronophenylalanine (BPA) as 11B carrier and 15N-L-Glutamine as 15N carrier with 500 ug/ml, SAS prostate cancer cells to assess cell killing and cell survival analysis was performed using the CCK-8 assay. For SAS cells, three repeats were performed with 0, 2, 4 and 6 Gy without or with BPA and 15N-L-Glutamine. Furthermore, dosimetry film (gafchromic EBT3 ) was employed to validate the accuracy of the delivered radiation dose.
Results
We have obtained the LETd of PCT at proton with low energy using Geant4. The average increment of LETd of PBCT and PNCT were 3.5% and 3.9%, compared to conventional proton therapy. Compared to exposure in the absence of boron and nitrogen, proton irradiation in the presence of BSH and 15N-L-Glutamine reduced SAS cells survival at 72 hours.
Conclusion
Our combined approach of MC simulation and biological experiments revealed that PCT holds promising potential for increasing the biological effectiveness of the proton therapy.