In this pilot study, MRI of the lungs of healthy adult volunteers will be performed at 3Tesla to assess image quality using a prototype chest coil and pulse sequence following inhalation of hyperpolarized 129Xe (xenon) gas. This study will take place at the Hospital for Sick Children, Toronto, Canada. Twenty subjects aged 18 to 75 will participate in this study. Xenon MRI is a non-invasive imaging technique that does not involve X-rays or ionizing radiation. Rather, this imaging method utilizes the same hardware and software principles that are used for conventional proton MRI of patients in a hospital. The investigators are testing the abilities of xenon MRI to see if it will produce lung images of equal or better quality to that of proton MRI.