Dosimetric evaluation of megavoltage X-ray and proton minibeam radiation therapy in brain tumor-bearing canines.
Healthy tissue toxicity is the main limitation for the treatment of brain tumors using radiotherapy (RT). Megavoltage X-ray Minibeam Radiation Therapy (MBRT) and proton Minibeam Radiation Therapy (pMBRT) are novel therapeutic approaches demonstrated to reduce healthy tissue toxicity, enhancing the therapeutic possibilities of challenging cases. Owing to the different radiation types delivering the dose, their dosimetric properties may make one approach more suitable than the other depending on tumor type and location. While both techniques have been extensively studied in small animal models, canine clinical studies provide a closer approximation to human conditions.
This study aims to compare the dosimetric performance of MBRT and pMBRT in canine brain tumors and to determine which modality provides more favorable dose distributions depending on tumor location.
Three representative cases were chosen, and MBRT and pMBRT treatments for a prescribed dose of 26 Gy to the planning target volume (PTV) were simulated using Monte Carlo methods. The in-depth evolution of the minibeam patterns was investigated for both modalities. The dose distributions within the PTV, healthy brain and surrounding tissues evaluated by calculating and comparing the corresponding peak, valley, and mean doses.
pMBRT achieves dosimetric superiority for tumors in the rostral cerebrum surrounded by highly heterogeneous tissue with one entry port. MBRT achieves optimal dose distributions in a two-beam configuration for deeper and more centered targets, where the reduced lateral spread of X-ray minibeams preserved dose heterogeneity.
In this dosimetric comparison of MBRT and pMBRT for the treatment of spontaneous canine brain tumors, the distinct in-depth physical behavior of X-ray and proton minibeams makes each modality more suitable for specific target locations to achieve optimal dose distributions. These findings provide valuable guidance for future veterinary clinical trials and represent an important step toward the clinical implementation of MBRT and pMBRT.
This study aims to compare the dosimetric performance of MBRT and pMBRT in canine brain tumors and to determine which modality provides more favorable dose distributions depending on tumor location.
Three representative cases were chosen, and MBRT and pMBRT treatments for a prescribed dose of 26 Gy to the planning target volume (PTV) were simulated using Monte Carlo methods. The in-depth evolution of the minibeam patterns was investigated for both modalities. The dose distributions within the PTV, healthy brain and surrounding tissues evaluated by calculating and comparing the corresponding peak, valley, and mean doses.
pMBRT achieves dosimetric superiority for tumors in the rostral cerebrum surrounded by highly heterogeneous tissue with one entry port. MBRT achieves optimal dose distributions in a two-beam configuration for deeper and more centered targets, where the reduced lateral spread of X-ray minibeams preserved dose heterogeneity.
In this dosimetric comparison of MBRT and pMBRT for the treatment of spontaneous canine brain tumors, the distinct in-depth physical behavior of X-ray and proton minibeams makes each modality more suitable for specific target locations to achieve optimal dose distributions. These findings provide valuable guidance for future veterinary clinical trials and represent an important step toward the clinical implementation of MBRT and pMBRT.
Authors
Fernandez-Rodriguez Fernandez-Rodriguez, Perrot Perrot, Benoit Benoit, Prezado Prezado
View on Pubmed