Reading a hard constraint against coverage in Elekta Monaco
A disqualifying limit is not one objective among many. Spend everything else before you spend it.
Written from documentation and not yet confirmed on a real Elekta Monaco. Control names may differ by version — if you use this system, the skill page has a button to confirm or correct it.
Until somebody does, this page is kept out of search results: naming your console in the title is a claim about it, and an unchecked claim is not one worth advertising.
Controls
| Cost function | Serial | |
| Power Law Exponent k | 1–4, start at 2 | departmental convention — verify against your protocol |
| Isoconstraint (EUD) | 5 % inside the limit | |
| Maximum Dose | optional, as a true ceiling | only for the disqualifying constraint |
This is where Monaco differs most and where a conversion has to be done by hand.
A disqualifying D0.03cc is a near-maximum dose. In Monaco that is a Serial cost function: the higher the power-law exponent k, the more the equivalent uniform dose is dominated by the hottest part of the structure.
Monaco's k is a small number, not the exponent from Niemierko's gEUD — vendor guidance puts the useful range around 1–4 with 2 as a starting point, and a published breast study found 2 ≤ k ≤ 4 optimal for the heart while leaving lung and LAD at k = 1. Treat any specific value as your department's convention rather than a conversion factor, and check it against your own protocol.
Set the isoconstraint 5 % inside the limit, run, and read the isoeffect. Monaco tells you what it achieved next to what you asked for, which makes it easier than most systems to see whether you have margin or are sitting on the line.
If you want a genuine hard ceiling rather than a biological one, add Maximum Dose alongside the Serial function. It is unforgiving and can dominate the plan, so use it for the constraint that disqualifies and not for the rest.
Why this works, and where the numbers come from →
The recipe is the console; the skill page is the reasoning and the papers behind it.
Same skill elsewhere:Accuray PrecisionVarian Eclipse