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Mismatch of posion of maximum values in Gamma analysis

I’m comparing PDD files in the software and noticed a slight mismatch in the reported dmax positions.

  • For the measured PDD file, dmax is at z = 1.41 cm, but in the curve window it shows 1.38 cm.

  • In my simulated PDD file, dmax is at 1.50 cm, but the curve window shows 1.49 cm.

Why does this discrepancy occur, and is there a way to correct it to improve the accuracy of the gamma index calculation?

Thank you for your help!

Dose profiles need to be interpolated to match the same spatial resolution, therefore small discrepancies (0.1 mm in your case) can be found between the original profile and the interpolated one.  Those interpolations do not degrade the accuracy of gamma analysis.