Author: Nina Burbure, Tawfik G. Giaddui, Shidong Li, Curtis Miyamoto, Jeremy Price, Bin Wang 👨🔬
Affiliation: FCCC at Temple University Hospital 🌍
Purpose: To evaluate the performance of KBP models for hypo-fractionated prostate and pelvic lymph nodes (LN) VMAT plans.
Methods: A KBP model (TUH KBP) was developed in Eclipse treatment planning system (version 16.1) using 75 previously treated definitive or post-operative prostate plans. The model is designed to be used for sequential boost or SIB prostate treatments. The performance of the model for hypo-fractionated (250 cGy for 28 fractions) prostate/prostate LN treatments was evaluated using 14 clinical treatment plans (8 prostate SV and 6 prostate/SV/LN plans). The plans were retrospectively reoptimized using the TUH KBP model and another model (WU KBP) provided by the vendor in a single iteration without human intervention.
Results: The PTV coverage was comparable for clinical plans and the KBP reoptimized plans. The maximum dose was (8 ± 2) %; (7±1) % and (6±1) % in clinical, TUHKBP and WUKBP plans. The average bladder V40Gy was (31± 9) %; (31± 9) % and (37 ±12) % and V65Gy was:(9±4); (9±4) % and (1±4) % for the clinical, TUHKBP and WUKBP plans respectively. The average rectum V40 Gy was:(23±10) %;(17±6) % and (20±8) % and V65Gy was:(2±2) %; (2±2) % and (3±3) % for the clinical, TUHKBP and WUKBP respectively. The average monitor units for the treatment plans were: 920 ± 135; 952±116 and 784 ±117 for the clinical, TUHKBP and WUKBP plans respectively.
Conclusion: The TUH KBP reoptimized plans showed a statistically significant reduction in Rectum V40Gy whilst similar and not statistically different changes in bladder V40Gy without adding significant complications to the treatment plans. The WUKBP model showed a statistically significant reduction in monitor units with significant increase in bladder V40Gy. The TUH KBP model has proved to be a useful tool to generate a high-quality clinical treatment plan for hypo-fractionated prostate and prostate LN treatments.