Investigating the sensitivity of NIPAM gel dosimetry in CyberKnife systems using MRI-based R2 mapping.

Motivation: The CyberKnife's high precision and complex dose gradients challenge traditional dosimetry techniques, but N-isopropylacrylamide (NIPAM) gel phantom can capture 3D dose distributions effectively. Goal(s): This study explores using NIPAM polymer gel dosimetry with MRI-based R2 mapping to verify dose distribution in the CyberKnife stereotactic radiation system. Approach: MRI-based R2 mapping. Results: Results showed a dose-dependent increase in R2 values, with a peak at a 30 mm depth, reflecting maximum dose accumulation. This method provides high spatial resolution, making it a promising alternative to conventional dosimetry. Impact: The findings suggest potential applications of NIPAM gel dosimetry in verifying dose delivery across various stereotactic treatments.