Clinical Radiation Physics Service

Division Of Clinical Sciences - Nci

Investigators

Linked publications & trials

Abstract

We have a series of initiatives utilizing our High Dose-Rate Remote Afterloader (HDR) using a small, high intensity 192Ir source for interstitial and intercavitary brachytherapy. The department now has two state-of-the-art Varian TrueBeam STX accelerators which are equipped with 120 leaf high definition multi-leaf collimators with leaf widths as thin as 2.5 mm. This renders them capable of performing frameless stereotactic radiosurgery (SRS), although a set of circular collimators with diameters ranging from 4mm to 25mm and an SRS planning module are included in the acquisition. The patient couches also provide for 6 Degrees-of-Freedom (6DOF) to greatly improve positional accuracy by permitting corrections for pitch, roll and yaw, in addition to the traditional longitudinal, lateral and vertical position adjustments. The treatment delivery parameters of these two accelerators are matched to within 0.5%, thus providing true redundancy, assuring that patients can continue to receive their treatments according to their fractionation schedule. These machines include the Edge Extracranial SABR Package that will permit them to deliver frameless stereotactic body radiation therapy (SBRT) using advanced motion management based on radiofrequency local positioning using implanted fiducial transponders and infrared cameras. The revised Edge package includes a Calypso radiofrequency positioning system, utilizing implantable fiducial transducers and real-time tracking capability. The real-time optical tracking utilizes an upgraded Optical Surface Monitoring System (VisionRT) system to monitor the body surface and to interrupt the treatment if the surface distorts (due to motion) and the clinical implementation of a prostate radiotherapy protocol using Calypso RF transponders to monitor prostate position and correspondingly gate the treatment delivery. ROB has acquired a new Elekta Flexitron 40 channel High-Dose-Rate (HDR) remote brachytherapy afterloader to replace its previous unit. Additionally, ROB has acquired a new B-K ultrasound unit, which has vastly improved imaging capabilities relative to the previous unit. We have acquired a couch-mounted stepper-stabilizer to improve needle insertion methodology and are working on adapting a motorized scanning system for the probe to speed image acquisition. ROB has a dedicated brachytherapy suite (B2-3643). This room is now clinically operational and has proved to provide greater flexibility in the layout of operative and support equipment, which is reflected in reduced patient time under anesthesia. ROB has installed a replacement CT Simulator. While similar overall to the existing unit, the new system has substantially more powerful processing power to accelerate image reconstruction. It also utilizes dual energy, sequential CT scans, which can be post processed to enhance the detection of Iodine, Calcium or other detectable elements utilized as bio-tracers for the functional imaging of tumors. ROB, in conjunction with NCI/CBIIT, is still in the process of upgrading its Radiation Therapy Patient Management and Treatment System (ARIA) from version 13.7 to version 16. The upgrade is now scheduled for mid-September, 2022. This system includes substantial improvements including migration to the NIH Active Directory user management system. It will also migrate from physical servers too a virtual server environment, which will provide improved hardware redundancy. ROB has also upgraded its Machine Shop to conform with current electrical standards as well as permitting the installation of more advanced fabrication equipment inn order to better support clinical research projects.