Stereotactic Radiotherapy: Potential Therapeutic Gain
Stereotactic radiotherapy, describes a more localized form of radiation that is delivered over a very short course of 1-5 treatments, using large doses per treatment (hypofractionated treatment). With stereotactic radiation approaches, it is possible to deliver a more sharply marginated form of radiation that is more sparing of surrounding tissue, allowing an increased dose to be delivered. This form of applied radiation is biologically ablative of tissue within the high dose volume and represents a potentially more effective method of eradicating liver lesions compared with prior radiotherapy techniques (21, 22, 23).In an ongoing Multi-Institutional
stereotactic radiotherapy dose escalation protocol, liver tolerance to radiation still has not been reached at a radiation dose level of 54Gy/3 fractions, as long as 30% of the hepatic tissue receives less than 15Gy total dose. The radiation does delivered in this study has been estimated as the biological equivalent of 160Gy in conventional 2 Gy radiotherapy fractions, assuming the alpha/beta ration = 10Gy, representing a far more biologically potent radiotherapy dose compared with prior “conventional” or standard conformal radiotherapy approaches (22, 23).
|
