Chemotherapy has saved the lives of many pets and people with cancer. But the treatment can be nearly as harsh as the disease. The large doses of chemicals needed to kill cancer cells can destroy other cells in the body, too, which can lead to serious side effects.

Research on the treatment of prostate cancer in dogs has taken a very different approach. Low doses of tiny radioactive gold bits, called nanoparticles, are injected directly into the tumor, where they target only cancer cells. This small but mighty onco-ammunition has been very effective against tumors in mice and has produced no adverse effects in dogs.

Because dogs are the only mammals other than men to develop aggressive prostate cancer, scientists have high hopes that the treatment will be as golden in humans as in their four-legged friends.