text: SEOP has successfully been used and is fairly well developed for He, Xe, and Kr for biomedical applications. Additionally, several improvements are under way to get enhanced and interpretable imaging of cancer cells in biomedical science. Studies involving hyperpolarization of Xe are underway, piquing the interest of physicists. There are also improvements being made to allow not only rubidium to be utilized in the spin transfer, but also cesium. In principle, any alkali metal can be used for SEOP, but rubidium is usually preferred due to its high vapor pressure, allowing experiments to be carried out at relatively low temperatures (80 °C-130 °C), decreasing the chance of damaging the glass cell. Additionally, laser technology for the alkali metal of choice has to exist and be developed enough get substantial polarization. Previously, the lasers available to excite the D cesium transition were not well-developed, but they are now becoming more powerful and less expensive. Preliminary studies even show that cesium may provide better results than rubidium, even though rubidium has been the go-to alkali metal of choice for SEOP.
  The hyperpolarization method called spin-exchange optical pumping (SEOP) is being used to hyperpolarize noble gases such as Xenon-129 and Helium-3. When an inhaled hyperpolarized gas like 3He or 129Xe is imaged, there is a higher magnetization density of NMR-active molecules in the lung compared to traditional 1H imaging, which improves the MRI images that can be obtained. Unlike proton MRI which reports on anatomical features of lung tissues,  XenonMRI reports lung function including gas ventilation, diffusion, and perfusion.