One of the techniques I have used is to have a patient try on a bra with an implant in the bra to get an ides of the size they would like to acheive. For example If you are a 36B and want to fill a 36C bra - try on a 36C bra and put implants in the bra to see approximately what size implant is needed to give you the desired volume. This will give you the size implant needed for the augmentation of the "normal" breast. The implant needed for the side that had the mastectomy can be estimated by the weight of the mastectomy specimen and the same volume added to that volume as will be added with the augmentation.
So for example, if the mastectomy specimen weighed 340 grams and you want to add 150 cc to augment the remaining breast , the reconstructed breast should have an implant volume of approximately 490 cc. Of course you need to discuss your particular situation with your plastic surgeon. Radiation can make reconstruction more difficult and you may want to consider a lift also on the augmented breast.
