Abstract: A device useful to block radiation (e.g., X-ray, gamma ray) leakage through a wall joint and screw holes in a lead-shielded structure is provided. The device includes a substantially planar lead strip which is at least the thickness of the lead sheeting covering the structure, and a lead strip holder adapted to hold the lead strip securely in place and attach the lead strip to a metal C stud such that when attached thereto, the lead strip forms a barrier which blocks radiation leaking through the wall joint and adjacent screw holes. Clips can be used to attach the lead strip holder to the stud, wherein each of the clips includes a U-shaped portion to frictionally fit onto a U-shaped portion of the lead strip holder. In various embodiments, the device can be used on vertical or horizontal wall joints.