Clinical Radiation Physics Service

Miller, Robert

Abstract

We have instituted routine dynamic Intensity Modulated Radiation Therapy (dIMRT). This is the most complex of IMRT treatments and requires considerable pre-treatment verification to ensure accurate execution. These treatments are delivered using our twin Clinac-21EX accelerators. A Hi-ART system (Tomotherapy Inc.) for delivering treatments via helical tomotherapy has been installed, accepted and is currently treating patients. This system provides ROB with cutting edge treatment technology to support future clinical trials. We have started a series of initiatives with our Nucletron High Dose-Rate Afterloader (HDR) , using a small, high intensity 192Ir source for interstitial and intercavitary brachytherapy. Our radiosurgery capability has been expanded with the acquisition of 3 new applicators with diameters of 5mm, 7.5mm and 10mm. A new Philips Brilliance 16 slice, large bore CT Simulator has received couch control upgrades. On-board imaging (OBI) has been installed on the newer Clinac-21EX. The final component of the Varian RPM Respiratory Gating system for providing gated radiation therapy has been acquired and we are awaiting delivery. Respiratory gating will improve targeting ability by compensating for regular respiratory motions during treatment. We have acquired two state-of-the-art scanning water phantoms, one for CT and Tomotherapy and the second for general accelerator use. These should greatly facilitate data acquisition for annual quality assurance as well as for research purposes. We have also had funding approved for the replacement of our oldest linear accelerator with a new unit. We are in the process of acquiring a replacement for our oldest Clinac-21EX accelerator, which we have had for over 12 years. Room renovation is scheduled to begin February, 2014,, with accelerator installation scheduled for summer of that year. The new machine will be a state-of-the-art Varian TrueBeam. This accelerator will be equipped with the new high definition multi-leaf collimator with leaf widths as thin as 5 mm. This will render it capable of performing frameless stereotactic radiosurgery (SRS), although a set of circular collimators and an SRS planning module are included in the acquisition. This will replace our current Radionics SRS system, which has been discontinued by the manufacturer. An upgrade to this accelerator has already been requested. This upgrade, the Edge Extracranial SABR Package for Truebeam will permit the unit to deliver frameless stereotactic body radiation therapy (SBRT) using advanced motion management based on radiofrequency local positioning using implanted fiducial transponders and infrared cameras..