This paper reports on the commissioning tests performed on a new GE Lightspeed RT wide-bore computed tomography (CT) scanner with GE Advantage Sim software. This paper focuses on the laser marking system, CT hardware and the interfaces between each component of the system, and generalises the findings to most CT simulation systems currently available. A discussion on the commissioning of the virtual simulator software will follow in a separate paper. Three phantoms were used (two constructed in-house) to assist with a range of tests covering aspects such as the laser patient marking system, CT hardware, and connections between the CT scanner, virtual simulator system and the treatment planning system (TPS) and VARiS. Tests performed showed the CT simulation system to be working within acceptable tolerances suggested in the literature, and baseline data have been obtained against which future comparisons of system performance have been made. Where no tolerances were available, we have suggested suitable values. While considering tolerances on Hounsfield number variation that may lead to a dose error in excess of 2%, we found that in the case of low-kV CT scanning the range of Hounsfield numbers for dense bone was outside the acceptable limits for potential dose errors and so users were advised not to perform radiotherapy planning CT scans with kV below 100 kV.

This paper continues the discussion on the commissioning tests performed on a new GE Lightspeed RT wide-bore computed tomography (CT) scanner, focusing on the GE Advantage Sim software (version 6.0).The tests performed and phantoms used to assess the virtual simulator functionality, including the 3D image display, contouring, treatment unit beam parameters, digitally reconstructed radiograph generation and image quality, isocentre generation and multi-modality image registration, are described.The series of tests performed showed the virtual simulation software to be working within acceptable tolerances suggested in the literature and baseline data have been obtained against which future comparisons of system performance have been made. Where no tolerances were available, we have suggested suitable values.