| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
|---|---|
| RIHSA | radioactive iodinated human serum albumin |
| RISA | radioactive iodinated serum albumin; radioimmunosorbent assay |
| RIU | radioactive iodine uptake |
| ALEC | artificial lung-expanding compound |