Quantification and characterization of radiation-induced changes to mandibular vascularity using micro-computed...

Area of Science:

• Oral and Maxillofacial Surgery
• Radiation Oncology
• Biomedical Engineering

Background:

• Head and neck cancer reconstruction faces challenges due to radiation therapy (XRT)-induced damage to surrounding tissues.
• XRT impairs bone and soft tissue repair, leading to wound healing complications, fractures, and osteoradionecrosis.
• The specific effects of XRT on bone vasculature have been poorly understood.

Purpose of the Study:

• To quantitatively analyze the degradation of bone vascularity caused by XRT.
• To utilize high-resolution micro-computed tomography for precise vascular tree metrics.

Main Methods:

• Male Sprague-Dawley rats received 35 Gy of fractionated XRT.
• Mandibles were harvested 28 days post-XRT, injected with Microfil contrast, and scanned using micro-computed tomography (18-μm voxels).
• Vascular parameters including vessel number, thickness, separation, connectivity, and volume fraction were analyzed.

Main Results:

• Irradiated mandibles showed a significant reduction in vessel volume fraction (0.016 vs 0.032, P ≤ 0.003) and vessel thickness (0.042 vs 0.067 mm, P ≤ 0.001) compared to controls.
• No significant differences were observed in vessel separation or number between groups.
• Stereologic analysis confirmed quantifiable diminution in irradiated vasculature.

Conclusions:

• XRT significantly degrades the quality and size of mandibular blood vessels, even if vessel number is retained.
• This study quantifies the detrimental effects of XRT on mandibular vasculature.
• Findings suggest potential for future therapeutic interventions targeting XRT-induced bone injury mechanisms.