METHODS
Five cm depth-fluence maps calculated by TPS and measured
by 2D array were compared using PTW Verisoft program
for the IMRT plans of 16 prostate patients. The percentage
of points passing through the (g) evaluation was found for
different distance to agreement (DTA) and dose difference
(DD)%.
RESULTS
When coronal fluence maps were compared, the percentage
of points passing through the (g) evaluation was obtained as
98.45 (95.5-100) for the low segment group and as 86.75 (73-
94) for the high segment group for 3 mmDTA/3% DD.
CONCLUSION
The percentage of points passing through (g) evaluation was
found lower for the high segment group than for the low segment
group. To minimize this uncertainty in the IMRT verification,
the use of a large number of segments should be avoided
to the extent possible.
Keywords: Intensity-modulated radiotherapy (IMRT); dosimetric verification; 2D array; gamma index
