Virtual Visit


         The Virtual Visit is a remote analysis of an institution’s dosimetry data using standard machine data. Through this audit, IROC Houston verifies that the dosimetry data is consistent with standard data for that make and model of accelerator. If the review is being requested due to an institution’s participation in the NCI’s National Clinical Trial Network (NCTN) clinical trials, it is paid for by NCI and is no cost to the institution. During the Virtual Visit, the site physicist is requested to complete several tasks:    


1). Complete the forms describing the radiotherapy equipment, as well as calibration and dose calculation techniques. This information will familiarize us with the institution’s practice and allow us to make appropriate dosimetric evaluations.    


2). Complete several tables of dosimetric data based on calculations from the treatment planning system. The virtual visit evaluates the basic dosimetry of the institution, including PDD (as a function of field size), output factors (including small fields for IMRT and SBRT), off-axis factors, and wedge factors.    


3). Submit documentation describing their quality assurance program, as well as calibration certificates for ion chambers and electrometers. The quality assurance program will be compared against the recommendations made in the AAPM TG-40 and TG-142 reports.    


         The submitted data will be evaluated by an IROC Houston physicist and used to generate a report detailing the results of the comparison, along with any recommendations made. This report will be reviewed by another IROC Houston physicist as well as the IROC Houston director to verify its accuracy. Upon completion of the report, it will be sent to the head physicist and head radiation oncologist at the facility.