Abstract: A shielding device for the protection of human embryo cells from the effects of radiation during examination by X-ray comprising a radiant absorbent protective screen rotatably secured to a supporting frame, the screen including a central protective plate of predetermined shape; a first plurality of protective displaceable sheets, a second plurality of protective sheets associated with said first protective sheets mounted in pairs and being rotatable on one pair of said first sheets and adjusting means to linearly displace the first protective sheets to vary the covering surface area of the screen.