Comparative Dosimetric Analysis of VMAT-Driven Total Body and Total Marrow Irradiation

Overview

This study evaluates the dosimetric differences between VMAT-based total body irradiation (TBI) and total marrow irradiation (TMI) in adult leukemia patients. TMI demonstrated significant reductions in organ-at-risk doses while maintaining treatment complexity and target coverage.

Background

Total body irradiation (TBI) is a critical component of conditioning regimens for hematopoietic stem cell transplantation but poses risks of significant radiation exposure to normal tissues. This exposure can lead to acute and late toxicities, necessitating the exploration of alternatives like total marrow irradiation (TMI), which aims to minimize these risks while preserving therapeutic efficacy. Understanding the comparative dosimetric profiles of TBI and TMI is essential for optimizing treatment strategies in leukemia patients.

Data Highlights

Key Findings

• TMI plans showed a statistically significant reduction in dose to all evaluated organs at risk compared to TBI (p < 0.001).
• Mean doses to the heart, kidneys, and liver were reduced by approximately 5–6 Gy.
• TMI provided improved dose homogeneity compared to TBI.
• TMI plans had significantly lower monitor units, segment number, and modulation factor than TBI plans.
• AI-based auto-segmentation facilitated standardized target delineation for TMI.

Clinical Implications

The findings suggest that TMI may offer a safer alternative to TBI by reducing radiation exposure to critical organs while maintaining effective treatment. Clinicians should consider the implications of these dosimetric advantages when planning treatment for adult leukemia patients.

Conclusion

VMAT-based TMI presents a promising approach to reduce organ-at-risk doses in leukemia treatment while maintaining plan quality. Further clinical validation is necessary to confirm these findings in practice.

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