Impact of the Enhanced Leaf Model In Eclipse v18.1 Compared with the Simple Leaf Model In Eclipse v15.6
Abstract
Purpose
Multileaf collimators (MLCs) are essential in radiotherapy, and their modeling in the treatment planning system directly affects dose accuracy. This study compares the performance of the Enhanced Leaf Model (ELM) in Eclipse v18.1 with the Simple Leaf Model (SLM) in Eclipse v15.6.
Methods
The Dosimetric Leaf Gap (DLG) was experimentally determined following the manufacturer’s recommendations, using a Novalis TX LINAC with a high-resolution multileaf collimator and energies of 6X, 10X, 6X FFF, and 10X FFF. Dosimetric comparison was performed using standard IMRT patterns (fixed fields with different fluences) and clinical TG-119 plans, evaluated in heterogeneous phantoms. Plan verification was carried out using Portal Dosimetry and the Delta4 phantom, complemented by independent dose calculations using RadCalc v7.3 and PRIMO.
Results
The ELM in Eclipse v18.1 demonstrated superior dosimetric performance compared with the SLM in Eclipse v15.6. In the analysis of standard patterns using portal dosimetry, gamma passing rates exceeded 90% (criterion 3%/2 mm/Th = 10%). For the TG-119 cases, evaluations using the Delta4 phantom and PRIMO exceeded 95%, while independent calculations with RadCalc yielded passing rates above 90% under the same criterion, confirming better agreement for the ELM compared with the SLM.
Conclusion
The Enhanced Leaf Model implemented in Eclipse v18.1 demonstrated superior dosimetric performance compared with the Simple Leaf Model in Eclipse v15.6. Verification using TG-119 cases, portal dosimetry, the Delta4 phantom, and independent calculations with PRIMO and RadCalc showed improved agreement between planned and delivered dose. These results support a more accurate representation of multileaf collimator behavior in Eclipse v18.1.