Individualized lung shields constructed from lead shot embedded in plastic.

Earle and Bagshaw (2) described a rapid optical method for preparation of complex field shapes for megavoltage therapy. In their technic, treatment simulation is carried out under conditions which are exactly similar to the therapeutic conditions. With optical methods, it is possible to produce a minified image of required size and shape, to guide construction of lung shields for the purpose of reducing dosage to these radiosensitive normal structures. At the same time prescribed dosage is delivered to areas of or presumed areas of tumor involvement. While it is a simple matter to prepare the complex field shape, the preparation of an individualized shield is a separate and more difficult problem. Highly desirable features include ease and rapidity of construction and also simplicity of modification, since modification is often necessary to obtain the final desired shape. We describe here a rapid, simply constructed lung shield which is readily modifiable and which fulfills the above requirements for a hi...