Use of computerized hot wire block cutter in radiation therapy

The ability to define the target volume more accurately and to deliver the radiation therapy with better precision in modern radiation oncology has resulted in radiation treatments with tighter margins in order to spare additional normal tissues. This type of treatment requires that the radiation shielding blocks be produced with high accuracy. The computer-driven block cutter has the advantage of being able to accept block contours designed from digital simulation and portal images as well as beam's-eye-view patterns produced during treatment planning. A computerized hot wire block cutter installed in our department has shown the capability to produce accurate blocks and has reduced the number of blocks requiring modifications by about one-third. The use of templates plotted on the transparencies facilitates the accurate mounting of the blocks has resulted in further reduction of the number of block modifications.