It was pointed out by Couch and Torrence that the extreme Reissner-Nordström solution possesses a discrete conformal isometry. Using results of Romans, it is shown that such a symmetry also exists when a non-zero cosmological constant is allowed. Introduction In [1], Couch and Torrence found a conformal isometry that interchanges the event horizon and null infinity J of an extremal Reissner-Nor...

Due to the angulation of the breast board used for tangential breast irradiation, additional normal lung tissues are included in the supraclavicular field. This work investigates a method to reduce the lung volume and dose delivered during supraclavicular irradiation for breast cancer. Ten patients included for this retrospective study received chest wall and supraclavicular irradiation followi...

Accurate alignment of linear accelerator table rotational axis with radiation isocenter is critical for noncoplanar radiotherapy applications. The purpose of the present study is to develop a method to align the table rotation axis and the MV isocenter to submillimeter accuracy. We developed a computerized method using electronic portal imaging device (EPID) and measured alignment stability ove...

Purpose To characterize the accuracy of noncoplanar image guided radiation therapy with the Varian Edge radiosurgery system for intracranial stereotactic radiosurgery (SRS) treatments by assessing the accuracy of kV/kV orthogonal pair registration with Optical Surface Monitoring System (OSMS) monitoring relative to cone beam computed tomography (CT). Methods and materials A Computerized Imagi...