MOSAIQ User's Guide - UCSF Radiation Oncology

MLC Conversion
CHAPTER 6: MLC Fit
MOSAIQ Intelligent [MLC] Conversion attempts to convert a static MLC leaf plan for a
particular machine to an equivalent plan for a different machine by mapping the leaves. In
general, if the source and target machines have equivalent leaf widths, then MOSAIQ can
map the leaves. Leaf mapping preserves manual edits as long as they remain within positional
limits. If the leaves cannot be mapped, then MOSAIQ will attempt to fit the leaves if the
following conditions are met: the field is a Static MLC (dynamic fields cannot be converted),
MLC Fit is a registered feature, and Shape record is present and a fit method is available.
When a fit is performed, any manual edits to the leaf positions are lost. If neither leaf
mapping (Intelligent Conversion) nor a fit can be performed in conjunction with a machine
change, then a simple 1:1 mapping will occur, and in most cases results in an inappropriate
MLC leaf field. Warning messages will appear in all cases in which direct leaf mapping
cannot be performed.
In the case in which the source machine is equipped with a 120 leaf MLC and the target
machine has either a 52 or 80 leaf MLC, MOSAIQ provides 3 options to handle the 2 to 1
mapping required by the 0.5 cm leaves.
Intrusive The relative positions of adjacent 0.5 cm leaves are mapped to match the
leaf that is extended furthest.
Average The relative positions of adjacent 0.5 cm leaves are averaged.
Retracted The relative positions of adjacent 0.5 cm leaves are mapped to match the
leaf that is most retracted.
If it is necessary to use MLC Fit and you want to preserve manual edits, you must copy the
field before changing machines. When MOSAIQ is connected to the new machine, you can
then run MLC Fit on the original plan and recover your edits from the copied field.
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