Commissioning and Implementation aspect of the Monaco TPS system at CMJAH

Abstract

Introduction: Modern Treatment Planning Systems (TPS), such as Elekta’s Monaco TPS, are essential in radiotherapy. Proper commissioning and Quality Assurance (QA) are essential to ensure accurate treatment planning and minimise side effects. This study aimed to validate the Monaco TPS (version 6.1.2.0) through photon beam data collection, analysis and dose calculation algorithm checks, ensuring optimal clinical outcomes and patient safety. Methodology: The verification of the Monaco TPS commissioning beam data for clinical use with four Elekta Versa HD linear accelerators at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) was performed in accordance with established dosimetric protocols. Photon beam data were collected using a PTW Beamscan water phantom and a PTW Unidos E electrometer with ionisation chambers and were compared with simulated data from the TPS for validation. Treatment plans for Volumetric Modulated Arc Therapy (VMAT) and 3D Conformal Radiation Therapy (3DCRT) techniques were generated and tested using the CIRS SHANE phantom for dose accuracy across various tissues and Perspex slabs. The Catphan 600 phantom was used for electron density (ED) calibration. Results: This work showed good agreement for open fields of 10 x 10 cm² or larger, but discrepancies were primarily observed in fields, particularly in those less than 5 x 5 cm². Collapsed Cone Convolution (CCC) models performed well for wedged fields, with minor limitations in smaller field sizes (FSs). Linac calibration accuracy was confirmed within ±1% and CT scan evaluations validated the ED to Hounsfield unit (ED-HU) curve, ensuring a reliable representation of tissue heterogeneities. Gamma analysis and IMRT/VMAT audits confirmed clinical acceptability. Dose delivery accuracy in prostate cancer treatment using 3D CRT and VMAT was within ±5%. Conclusion: This study effectively verifies and validates the commissioned Monaco TPS data at CMJAH, thereby confirming the accuracy of dose calculations and adherence to international commissioning standards for clinical implementation.