DropScaleless is an option for
FCLoopIsolate, ApartFF,
FourDivergence and other functions. When set to
True, all loop integrals that do not contain a
FeynAmpDenominator, i.e. consist of only scalar products
but no denominators, are set to zero.
FCLoopIsolate[SPD[l, q], {q}]\text{FCGV}(\text{LoopInt})(l\cdot q)
FCLoopIsolate[SPD[l, q], {q}, DropScaleless -> True]0