Estimation of external radiation dose to caregivers of patients treated with radioiodine after thyroidectomy.

Due to the remarkable increase in thyroid cancer cases, the number of patients treated with radioiodine (I) shows a sharply increasing trend in recent years. Accordingly, radiation exposure of other people, particularly caregivers or comforters, after release of patients from hospitals is getting more attention than ever. In the present study, empirical equations are proposed for estimation of doses to caregivers.

Stable stationary vortices and traveling oscillatory vortices in a stenotic fluid-flow channel.

A shearing zonal flow of viscous fluid near a boundary perturbation can generate vortices that either remain attached near the boundary or detach to be abruptly carried downstream. At low speed a stationary attached vortex develops downstream from the perturbation. At higher speeds an array of traveling vortices forms, with successive rolls rotating in opposite directions.