RADIATION RISK-ESTIMATION BASED ON ACTIVITY MEASUREMENTS OF ZIRCONIUM-OXIDE IMPLANTS

Implants made from zirconium dioxide exhibit higher specific radionucl ide activities of the uranium-radium and thorium series than metallic and alumium implants. This study presents data on activity measurement s performed on different samples of ZrO2 raw material (powder) and on the ceramic joint heads belonging to it to formulate a correlation bet ween the specific radionuclide activities of the uranium-radium and th orium series in the raw material, the flux density of the alpha partic le leaving the implant surface, and the annual dose of the tissue surr ounding the implant. Based on this experimental study, an equation for defining the limits of the specific activities in raw material is pro posed, taking into account the long-lived radionuclides (key nuclides) of the uranium-radium and thorium series weighted with their relative dose contributions from alpha emitters. (C) 1996 John Wiley & Sons, I nc.