What is this all about?

Varian's DMLC is an option for the C-Series Clinac which allows to deliver sliding window treatments.
For planning clinical IMRT treatments, we use CadPlan (current version 6.3.5) with the Helios inverse planning module. In CadPlan, the dynamic leaf sequences are generated by the LMC (Leaf Motion Calculator), taking a fluence distribution computed by Helios as the input, generating a dynamic leaf sequence (the so-called DVA file) as output.
The DVA file (embedded in the treatment plan) is the exported to the VARiS/Vision environment. From VARiS it is then uploaded to the MLC controller and delivered on the Clinac (80leaf MLCs).

For testing, arbitrary testpatterns (like mathematical patterns or grayscale images) can be fed into the LMC as well, and converted to DVA files.

One focus of these pages is a nice feature of the DMLC system: the possibility of logging MLC system parameters during DMLC treatments. During the sliding window execution, all data necessary to reconstruct the treatment are logged on the MLC controller. The spatial and time-resolution are high enough to allow accurate reconstruction for clinical treatments. Developing the tools to analyse the vast amount of data is a work in progress. Only some aspects can be demonstrated here.

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