KEY POINTS
- This technical development and validation study evaluated macro Monte Carlo dose calculation for monoenergetic electron beams from 50 to 250 MeV in homogeneous and heterogeneous phantoms and two patient computed tomography datasets.
- The framework used slab-based transport at energies of 25 MeV or higher and sphere-based transport below 25 MeV, with EGSnrc serving as the reference calculation method.
- In phantom testing, gamma passing rates exceeded 97% with 2%/1 mm criteria and 99% with 2%/2 mm criteria. Integrated depth-dose curves and lateral profiles agreed within 2% of the maximum dose.
- In the head-and-neck and prostate datasets, gamma passing rates exceeded 94% and 96%, respectively, with 2%/1 mm criteria, and 97% and 99% with 2%/2 mm criteria.
- Computational efficiency improved by up to 27-fold overall and by up to 11-fold and 12-fold in the head-and-neck and prostate datasets, respectively.
CLINICAL TAKEAWAY
Macro Monte Carlo may support faster treatment-planning research for very high energy electron and FLASH radiotherapy while maintaining close agreement with a general-purpose Monte Carlo reference. The evidence remains technical and preclinical because validation used phantoms, two patient datasets, and simple monoenergetic beams rather than optimized clinical plans.