| RAI | radioactive iodine; radioactive isotope; resident assessment instrument; resting ankle index; right atrial inversion; right atrial involvement |
|---|---|
| RAID | radioimmunodetection |
| RAIS | reflection-absorption infrared spectroscopy |
| RAITI | right atrial inversion time index |
| RAIU | Radio-Active Iodine Uptake |
| RAIU | radioactive iodine uptake |