Boron microlocalization in oral mucosal tissue: implications for boron neutron capture therapy

Area of Science:

• Oncology
• Radiochemistry
• Biomedical Engineering

Background:

• Boron neutron capture therapy (BNCT) is an emerging cancer treatment for glioma and melanoma.
• Clinical trials are ongoing, with new facilities being built globally.
• Acute oral mucositis has been observed in patients, indicating a potential complication.

Purpose of the Study:

• To investigate the microdistribution of boron-10 (10B) in oral mucosa.
• To correlate 10B distribution with the biological effectiveness of the neutron capture reaction.
• To compare the effects of two boron delivery agents, BSH and BPA, on oral mucosa.

Main Methods:

• Utilized a rat ventral tongue model to study boron delivery agents BSH and BPA.
• Employed high-resolution ion microscopy to quantify 10B concentrations in different tissue regions.
• Assessed oral mucosal response (ulceration) to BNCT irradiation and calculated Compound Biological Effectiveness (CBE) factors.

Main Results:

• 10B concentrations were lower in the epithelium with BSH compared to BPA.
• Lamina propria showed higher 10B levels than epithelium for both agents, more so with BSH.
• BSH demonstrated reduced radiation sensitivity and a significantly lower CBE factor (0.29) than BPA (4.87).

Conclusions:

• Microdistribution of 10B significantly impacts oral mucosa response to BNCT.
• Oral mucositis complications are more likely with BPA-based BNCT protocols.
• High-resolution analysis of 10B in human oral tissue is crucial for applying experimental CBE factors clinically.