Program Information
Initial Experience with Pinnacle3 Auto-Planning On Field Matching
S Wang1*, D Zheng1 , W Zhen1 , Y Lei1 ,X Zhu1 , X NI2 , C Enke1 , S Zhou1 , (1) University of Nebraska Medical Center, Omaha, NE, (2) The First Hospital of Longyan Affiliated to Fujian Medical University, Longyan, FUJIAN
Presentations
SA-B-BRD-8 (Saturday, March 5, 2016) 10:30 AM - 12:30 PM Room: Grand Ballroom D
Purpose:Pinnacle3 auto-planning (AP) was introduced to improve labor-intensive planning process and plan quality consistency. It utilizes progressive optimization to create planning structures, based on anatomical relationships among the PTVs and OARs, and iteratively tune the planning objectives during optimization. Our study evaluated AP planning on field matching between upper neck IMRT and lower neck 3DCRT fields, a more challenging problem for IMRT planning.
Methods:Twelve patients treated with matching upper neck IMRT and lower neck anterior-posterior opposing fields were studied retrospectively. A generic AP technique was created by retrospectively sampling the institutional planning objectives of target volumes and anatomical OARs, excluding planning structures created by the planners. The AP composite plans with AP IMRT fields and clinical lower neck 3DCRT beams were compared to the clinical composite plans used for treatments. PTV coverage in the matching region, mean doses to the parotids, maximum doses to the spinal cord and brainstems, and plan conformity (prescription dose spillage) were evaluated. Mann-Whitney U-Test was used to compare between AP and clinical plans.
Results:Overall PTV coverage were comparable, but AP plans achieved significantly better PTV coverage in the matching area, and significantly lower mean dose to parotids and max dose to brainstem (P<0.05). The max dose to spinal cord was on average lower in the AP plans, but not statistically significant. On the other hand, the prescription isodose volumes outside the PTVs were significantly larger in the AP plans, indicating inferior conformity in the AP plans than the clinical plans.
Conclusion:With an expedited planning process with much less human-thought process, AP results in better PTV coverage in the matching area and better OAR sparing for head-and-neck patients treated with combined IMRT and 3DCRT fields. Further improvement is necessary to achieve better plan conformity.
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