Clinical evaluation of the golden beam data in the monaco treatment planning system for the harmony pro and infinity linear accelerators

BACKGROUND: Accurate dose calculations in radiotherapy depend on high-quality beam models in the Monaco treatment planning system (TPS). The accelerated go live (AGL) workflow, using a golden beam data (GBD) model, has improved beam modeling accuracy for various linear accelerators (linacs). However, similar studies specifically for the Harmony Pro, recently introduced for online adaptive radiotherapy, have not yet been reported internationally. Moreover, studies on dosimetric differences between TPS beam models with GBD and those with measured beam data (MBD) are limited, and no such studies have been published specifically for Elekta linacs. PURPOSE: This study aimed to assess the clinical performance of GBD in the Monaco TPS for the harmony pro and infinity linacs. METHODS: Beam tuning and data collection were performed on the harmony pro and infinity linacs based on GBD. Subsequently, percentage depth doses (PDDs), off-axis dose profiles, output factors (OFs), absolute doses, and test fields were measured to evaluate the GBD model. Additionally, 31 clinical plans from multiple anatomical sites, including 17 conventional fractionated radiotherapy (CFRT) plans and 14 stereotactic body radiotherapy (SBRT) plans, were designed using the Monaco TPS (GBD model) and practically tested. An Infinity linac with MBD was introduced as a control. RESULTS: PDDs and profiles on both GBD linacs showed 100% passing rate (2%/2 mm). OFs and absolute doses on both GBD linacs agreed within ±1% and ±1.5%, respectively. Additionally, verification of the test fields yielded passing rates above 98% (2%/2 mm) for both GBD linacs. Furthermore, for CFRT plans, measurements on three linacs achieved a passing rate above 95% (3%/2 mm). The absolute dose deviations were within 3%, whereas one MBD linac case exceeded 3% (-3.73%). For SBRT plans, the gamma passing rates were 98.18 ± 1.58%, 98.76 ± 1.54%, and 94.72 ± 0.04% (3%/2 mm) and 96.69 ± 1.96, 96.29 ± 2.26, and 89.51 ± 0.06% (2%/2 mm), for the two GDB linacs and the MDB linac, respectively. The absolute dose deviations were within 3%, whereas two MBD linac cases exceeded 3% (-3.51%, -4.50%). CONCLUSIONS: The harmony pro-GBD and infinity-GBD linac results demonstrated strong agreement with GBD. Clinical plans designed with Monaco TPS (GBD model) were clinically acceptable when delivered on both GBD linacs. Although the test results of GBD model plans delivered on the Infinity-MBD linac showed certain differences compared to those on the two GBD linacs, most plans remained acceptable. This indicates that GBD-based modeling in Monaco TPS offers reliable clinical performance across different linac types.