Extending culture time to improve Mitotic Index for cytogenetic dosimetry.

Compared to the conventional 48-hour protocol, extending the culture length to 72 hours significantly increased the Mitotic Index and the number of first-division metaphases of irradiated lymphocytes, providing slides with a better scorable metaphase density. Extending the culture time to 72 hours, combined with FPG staining to score exclusively first-division metaphases, improved the counting of dicentric chromosomes. The methodology presented and discussed in this study can be a powerful tool for dicentric-based biodosimetry, especially when exposure to high radiation doses is involved.