M e s o t h e l i o m a

Linear energy transfer (LET) describes the rate at which a type of radiation deposits energy as it passes through tissue. Higher levels of deposited energy cause more cells to be killed by a given dose of radiation therapy. Different types of radiation have different levels of LET. For example, x-rays, gamma rays, and electrons are known as low-LET radiation. Neutrons, heavy ions, and pions are classified as high-LET radiation.
Most high-LET radiation is investigational treatment. The cost of the equipment and the amount of specialized training needed to perform high-LET radiation therapy restrict its use to only a few facilities in the United States.