Diapositive 1

Dublin 2018

Zhen et al

• Found:

– 3%/3mm showed no correlation that indicates DVH errors

decrease with increasing gamma pass rates

– Significant number of False Negatives (Gamma>95% but

DVH errors>5%)

– Correlation increases as reduce %/mm (though still weak)

– Inverse correlation found in some cases (DVH errors larger

for higher pass rates)

• Concluded:

– Gamma pass rates don’t correlate to clinically relevant

DVH metrics

– Action levels presume a strong correlation

– DVH based metrics? Vs ‘simple’ gamma metric?