Project Sunshine was a secret set of experiments carried out by the Atomic Energy Commission starting in 1953. They were testing radioactivity levels of nuclear fallout, especially the strontium-90 isotope. The body doesn't easily recognize the difference between strontium-90 and calcium, and they were measuring the levels of it deposited in bones and teeth, measured in 'sunshine units'. Bodies of stillborn and deceased babies were obtained from unofficial third-party sources, and without consent.
A related test was done at MIT, in which children with disabilities were given cereal containing radioactive tracers. These experiments were co-sponsored by the AEC, which wanted data on how the radioactive isotopes were deposited in the body, and the Quaker Oats company, which was interested in where the nutrients in the cereal were used in the body.
Project Sunshine is also a volunteer, non-profit organization, providing free programs and services to kids with cancer, AIDS, and other terminal illnesses. I can't help but assume that the name isn't just a coincidence.