Researchers Oleg N. Vassiliev and Radhe Mohan, affiliated with the University of Texas MD Anderson Cancer Center, have developed a novel approach to solving the Boltzmann transport equation, which could significantly improve proton beam therapy planning and delivery. Their work was recently published in the journal Medical Physics.
Proton beam therapy is a type of radiation therapy that uses protons rather than x-rays to treat cancer. It is often preferred for certain tumors due to its ability to deliver high radiation doses to the tumor while sparing surrounding healthy tissue. However, accurate calculation of the dose distribution is crucial for effective and safe treatment.
The researchers’ new solver uses an iterative procedure to solve the Boltzmann transport equation, which describes the statistical behavior of a large number of particles. Their algorithm accounts for Coulomb scattering and nuclear reactions, using the same physical models as the most rigorous Monte Carlo systems. This ensures a low level of systematic errors. Unlike Monte Carlo methods, their solver does not involve random sampling, which means the solution is not contaminated by statistical noise. This results in lower overall uncertainties and orders of magnitude faster calculations.
The researchers have developed prototype software and completed its testing for calculations in water. They calculated fluence spectra, depth doses, and three-dimensional dose distributions for narrow Gaussian beams of 40-220 MeV protons. The calculations were completed in just 5-11 milliseconds for depth doses and fluence spectra at multiple depths, and 31-78 milliseconds for Gaussian beam calculations. All calculations were run on a single Intel i7 2.9 GHz CPU. Comparison of their solver with Geant4, a widely used Monte Carlo toolkit for the simulation of the passage of particles through matter, showed good agreement for all energies and depths. In the 1%/1 mm γ-test, which measures the difference between their doses and Geant4 doses at the same point, the pass rate was 0.95-0.99.
This new solver could have practical applications in the energy industry, particularly in the field of radiation therapy. Faster and more accurate dose calculations could lead to more efficient and effective treatment planning, potentially improving patient outcomes. Additionally, the ability to calculate fluence spectra is particularly useful for calculating relative biological effectiveness, which is important for advanced radiobiological models.
In conclusion, Vassiliev and Mohan’s novel Boltzmann equation solver offers a promising advance in proton beam therapy, with potential applications in the broader energy sector. Their work demonstrates the value of innovative computational methods in improving the accuracy and efficiency of radiation therapy.
This article is based on research available at arXiv.