Program Information
Implementation of the RadCalc Image Analysis Tool for IMRT QA
A Soldner1*, C Fitzherbert2, F Zhou2, C Hand2, (1) University of Pennsylvania, Philadelphia, PA (2) Albert Einstein Medical Center, Philadelphia, PA
Presentations
SU-F-T-302 (Sunday, July 31, 2016) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:To assess RadCalc as a means for analyzing fluence maps of IMRT QA patient plans. Eclipse generated fluence maps were compared to RadCalc fluence maps generated from both Eclipse parameters and from dynalog trajectory files.
Methods:Six IMRT plans consisting of fifty individual fields were compared both field-by-field and as composite plans. These plans were exported from Eclipse to RadCalc. Each plan was then delivered in QA mode on a Varian Clinac iX, while recording and saving the dynalog trajectory files. These files were then imported into RadCalc, providing three sources of generating fluence maps: Eclipse, RadCalc, and dynalog files. Using the image analysis tool in RadCalc, a gamma analysis was then performed as a point-by-point comparison for each IMRT field. The Eclipse fluence map was used as the baseline for each comparison.
Results:Based on the manufacturer’s recommendations, all fields were normalized to the maximum pixel value within each Eclipse field. All data was analyzed using a gamma index of 3mm/3% with passing criteria of 90%. For both dynalog analysis and RadCalc fluence analysis, 48/50 created fluence maps passed at greater than 90% when compared with the Eclipse baseline. In analyzing the composite of each of the six patients’ plans, all plans passed over 90%.
Conclusion:Using the dynalog trajectory files in combination with RadCalc Version 6.3 image analysis is a promising metric for verifying IMRT QA passing rates. Notably, if a field failed, it did so for both dynalog and RadCalc compared to Eclipse. This suggests RadCalc can accurately simulate fluence maps, with similar results to dynalog comparisons. Limitations within the RadCalc software were discovered in the analytical process such as pixel resolution and the inability to set minimum threshold values. Comparisons could be extended to include dose map and distance to agreement analysis by expanding software capabilities.
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