Question

which therapy is associated with light waves, but not sound waves?
breaking down kidney stones
acoustically targeting the delivery of a drug
cauterizing an incision or wound
ablating tumors

Explanation:

Breaking down kidney stones can use sound - wave based lithotripsy. Acoustically targeting drug delivery uses sound waves. Ablating tumors can be done with methods using sound waves. Cauterizing an incision or wound often uses heat or light - based methods and not sound waves.

Answer:

cauterizing an incision or wound