Dictionary attribute prescribedDose makes no difference in resulting dose

[xskere]

In https://github.com/SlicerRt/SlicerRT a dose engine using pyRadPlan was added, however the max dose calculated would always be a bit over 1Gy.

After investigating a bit I noticed (in pyRadPlan/plan/_plans.py) that there was a key in the pln that was prescribedDose:

    pln_dict_camel = {
        "radiationMode": "photons",  # either photons / protons / carbon
        "machine": "Generic",
        "numOfFractions": 30,
        "prescribedDose": 60.0,
        "propStf": {},
        # dose calculation settings
        "propDoseCalc": {},
        # optimization settings
        "propOpt": {},
        "propSeq": {},
        "multScen": scen_dict_camel,
    }

This was not set in SlicerRT (while creating the dict, before calling create_pln), so to test it I hardcoded, using the prescribedDose key, the Rx dose to be 60.0 as well.
However, this made no difference and the max dose was also around 1Gy.

After that, I looked through the pyRadPlan code and saw that it seems that prescribedDose and prescribed_dose are both present in the code, but they are only referenced in pyRadPlan/plan/_plans.py in three places (The docstring describing the field, the field definition and an example in the main block), but is never read.

Is it that this a bug? Or is it that their usage is not implemented yet? And, if not, how would this need to be solved?

[wahln]

Yeah, this property is currently a bit unfortunate.

• prescribedDose is an alias for prescribed_dose to allow model validation from matRad
• Currently, this value does not do anything, as the optimization objective's dose parameters together with the number of fractions decides the absolute dose. pyRadPlan currently always then returns the dose per fraction. prescribed_dose was intended for future purposes like normalization of the plan.

[cpinter]

Thank you for the quick answer! We'd like to use it for now for forward planning. My assumption, looking at the maximum dose, is that the prescription (per fraction) is always 1, correct? Do you think it is reasonable for now to simply scale up the resulting dose by the prescription to see the total dose?