Calculations of Human Salivary Gland Cell Survival Rate After Proton and Carbon-12 Minibeam Irradiation

แนวคิดหลัก

Proton and carbon-12 minibeam therapies demonstrate a significant advantage over conventional homogeneous irradiation in sparing healthy tissues at the entrance to the target volume while achieving comparable tumor cell death rates.

บทคัดย่อ

• Bibliographic Information: Svetlichnyi, A.O., Savenkova, S.D., & Pshenichnova, I.A. (2024). Calculations of the cell survival rate after irradiating with minibeams of protons and 12C. arXiv preprint arXiv:2411.14589v1.
• Research Objective: To evaluate the efficacy of proton and carbon-12 minibeam therapies compared to homogeneous irradiation in sparing healthy tissues while effectively targeting tumor cells.
• Methodology: The researchers used Geant4 simulations to model the propagation of proton and carbon-12 minibeams in a water phantom. They then calculated the survival probabilities of human salivary gland cells representing healthy and tumor tissues using the modified microdosimetric kinetic model. Finally, they compared the results of minibeam irradiation with those of homogeneous irradiation.
• Key Findings: Minibeam therapies, with both rectangular and hexagonal grid arrangements, resulted in significantly higher survival rates (60-80%) for healthy cells at the phantom entrance compared to homogeneous irradiation (30-40%). Both minibeam and homogeneous irradiation achieved similar tumor cell inactivation rates (85-90%) within the target volume. Notably, carbon-12 minibeams did not fully overlap in the target volume, leading to variations in cell survival rates depending on the grid arrangement.
• Main Conclusions: Minibeam therapies, particularly with protons, offer a promising approach to reduce damage to healthy tissues while maintaining effective tumor control. The study highlights the importance of considering minibeam geometry and the potential for dose-volume effects in optimizing treatment plans.
• Significance: This research contributes valuable insights into the potential benefits of minibeam radiotherapy, particularly for deep-seated tumors where minimizing damage to surrounding healthy tissues is crucial.
• Limitations and Future Research: The study was conducted using a water phantom, which may not fully represent the complexities of human tissues. Further research using biological models and clinical trials is necessary to validate these findings and optimize minibeam parameters for clinical applications.

สถิติ

Minibeams of 0.5 mm FWHM were used.
The center-to-center distance between minibeams was 2 mm.
A 60 mm wide spread-out Bragg peak (SOBP) was centered at 130 mm depth for both protons and carbon-12.
The target volume received a dose of 5.1 Gy×RBE.
Approximately 10% survival of tumor cells was achieved in the target volume.
60-80% of cells survived at the phantom entrance (0-20 mm depth) after minibeam irradiation.
30-40% of cells survived at the same depth with homogeneous irradiation.
85-90% of cells were inactivated in the SOBP (100-160 mm depth) by both minibeams and homogeneous irradiation.

คำพูด

"The advantage of minibeams over homogeneous irradiation in sparing healthy tissues proximal to the tumour was demonstrated."
"The cells are inactivated only in ∼10% of the entry volumes because they are directly covered by the minibeams."
"In contrast, after homogeneous irradiation there are no parts of the entrance volumes with S > 0.7."

ข้อมูลเชิงลึกที่สำคัญจาก

Calculations of the cell survival rate after irradiating with minibeams of protons and $^{12}$C

by A.O. Svetlic... ที่ arxiv.org 11-25-2024

https://arxiv.org/pdf/2411.14589.pdf