In retrospective plan comparisons of ten previously treated patients with cancer and two clinical SBRT cases, physicists at Swedish Cancer Institute (SCI) in Seattle, WA have discovered that Elekta's latest release of Monaco treatment planning system - version 3.20 - provides significant benefits in dose conformity, delivery efficiency and sparing of organs-at-risk. SCI has been evaluating Monaco 3.20 since April.
In VMAT planning cases, physicists led by SCI Medical Physicist Dr Daliang Cao, compared Monaco 3.20 with the previous version of Monaco and found that Monaco 3.20 with Segment Shape Optimization (SSO) can provide much more uniform target dose without significantly compromising the sparing of critical normal structures. Compared with the previous version, they also observed that Monaco 3.20 reduced beam delivery time by 37 per cent (1.3 minutes) in some cases.
The new SSO enables improved dose conformity, plan quality and delivery efficiency through its approach to smoothing and clustering segments, then optimising beam weights and shapes. Powered by the Monte Carlo algorithm, the results are plans that improve sparing of organs-at-risk and dose conformality.
In addition to improved plan quality over the previous Monaco release, with SSO, Monaco VMAT can reduce the number of segments and therefore the amount of MLC leaf motion in the plan. The result is a 30 to 50 per cent improvement in delivery efficiency, according to Cao.
In SCI's SBRT cases the physicists found that Monaco VMAT planning takes just a few hours to obtain a reasonable plan, compared with the one- to two-day process using the centre's existing VMAT planning system.