Micro-radiosurgery: A new concept for radiotherapy based upon low energy, ion-induced nuclear reactions

摘要

Traditionally, proton radiotherapy has required the use of high energy proton beams (50--200 MeV) which can penetrate into a patients body to the site of a tumor that is to be destroyed through irradiation. However, substantial damage is still done to healthy tissue along the path of the incident proton beam, as 40% of that done at the tumor site. We propose a new concept for the production and delivery of energetic protons for use in medical radiotherapy, based upon the fact that low energy, ion-induced nuclear reactions can produce radiation products suitable for use in radiotherapy applications. By employing specially fabricated ''conduit needles'' to deliver beams of energetic ions to selected target materials plugging the end of the needle, ion beam-induced nuclear reactions can be generated at the needle tip, emitting reaction-specific radiation products directly at the tumor site In this paper, we show that the 13.6 MeV protons produced by the d((sup 3)He,p)(sup 4)He nuclear reaction can deliver a lethal dose (7 krad) of radiation to a 4.4 millimeter sphere of tissue in only 30 seconds using a 1 microamp, 800 keV (sup 3)He ion beam. If also proven clinically feasible, the use of low energy, ion-induced nuclear reactions would allow the utilization of relatively inexpensive, compact, low-energy ion accelerators for proton radiotherapy and minimize unintended radiation damage to healthy tissue by providing much greater precision in controlling the irradiated volume.