Radiation dose, for example, is precisely measured - we know exactly how much radiation the body is exposed to during therapy. mRNA products work by making our cells produce the desired protein/drug. There is no way of controlling how many cells are producing the drug and for how long they are producing it - ergo there is no way of controlling the dose. I hate to break it to you but they have found people producing spike protein over 3 years after getting the covid shot.