In X-ray radiotherapy accelerators, neutrons are produced mainly by ( , n) reaction when high energy X-rays interact with high Z materials of the linear accelerator head. These materials include the lead (Pb) used as shielding in the collimator, tungsten (W) target used for the production of X-rays and iron (Fe) in the accelerator head. These unwanted neutrons contaminate the therapeutic beam a...

PURPOSE Craniospinal irradiation poses technical difficulties that may be addressed with the use of the newer technologies that have become available over the past decade. The use of CT simulation allows improved target localisation and beam geometry definition while significantly reducing the treatment simulation time. We have developed a CT-based technique for whole CNS irradiation in the sup...

PURPOSE Commissioning beam data for proton spot scanning beams are compared for the first two Varian ProBeam sites in the United States, at the Maryland Proton Treatment Center (MPTC) and Scripps Proton Therapy Center (SPTC). In addition, the extent to which beams can be matched between gantry rooms at MPTC is investigated. METHOD Beam data for the two sites were acquired with independent dos...

INTRODUCTION The conventional fat saturation scheme for thin-slice fMRI is to use a 90° flip angle, spatially non-selective, 1D RF pulse at fat resonance frequency to rotate fat spins (or water spins under a B0 frequency offset that equals the fat-water frequency difference) in the whole 3D space to transverse plane. This scheme relies on a sufficiently strong following crusher gradient to remo...

For specific radiation therapy (RT) treatments, it is advantageous to use the isocenter-to-couch distance (ICD) for initial patient setup.(1) Since sagging of the treatment couch is not properly taken into account by the electronic readout of the treatment machine, this readout cannot be used for initial patient positioning using the isocenter-to-couch distance (ICD). Therefore, initial patient...