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Table 1 Absolute and Relative gamma evaluation comparison between films irradiated on the MRIdian in an MR environment compared to those irradiated on the Varian Edge linac in a non- MR environment for three open field sizes

From: Clinical utility of Gafchromic film in an MRI-guided linear accelerator

  3%/3 mm 3%/1 mm 2%/2 mm
Open fields (cm2) MRIdian Edge MRIdian Edge MRIdian Edge
Absolute gamma results
1.66 × 1.66 99.8 98.0 98.4 94.3 98.2 93.3
4.98 × 4.98 100 100 95.1 97.3 99.1 97.9
9.96 × 9.96 100 99.9 98.6 100 99.8 98.9
Average 99.9 99.3 97.4 97.2 99.0 96.7
Standard deviation 0.1 1.1 2.0 2.9 0.8 3.0
Relative gamma results
1.66 × 1.66 100 98.1 97.1 93.3 95.9 92.6
4.98 × 4.98 99.9 99.6 92.6 97.5 97.9 98.0
9.96 × 9.96 100 99.9 98.2 98.8 99.8 98.9
Average 100.0 99.2 96.0 96.5 97.9 96.5
Standard deviation 0.1 1.0 3.0 2.9 2.0 3.4
  1. Gamma pass criteria of 3%/3 mm, 3%/1 mm and 2%/2 mm were used for analysis