Protons can treat some pregnant patients
Changran Geng, a researcher from Massachusetts General Hospital, and colleagues from Rensselaer Polytechnic, UC San Francisco, and Harvard Medical, have designed phantoms that simulate 31 organs for the mother and 3 separate fetuses of different development. The study was designed to compare the integral fetal dose after conventional radiotherapy (3D-CRT) and two delivery methods of proton therapy, passive scattering (PPT) and pencil beam scanning (PBS).
From article: "They calculated the ratios of the dose received by the fetus for radiotherapy with a prescribed dose of 52.2 Gy(RBE) divided by that of a CT scan of the mother's head. For PBS, the mean dose equivalents were only about four times larger than that of the CT scan. For photon therapy, the ratios ranged from 30 to 44 with the growing fetus, while for PPT, the ratios were highest, decreasing from 500 to 180 as the fetus grew."
Read full article from Medical Physics Web here