THE USE OF CUSTOMIZED SPREADSHEETS IN RADIATION-THERAPY

A number of radiation-therapy-related uses based on a commercially ava ilable spreadsheet program have been developed at our facility. The gr aphics and display capabilities inherent in these spreadsheet programs allow for concise visual results. The spreadsheets are used as an ind ependent check for several types of radiation therapy dose calculation s. External beam - a spreadsheet will verify the monitor units (Mu) or time required to deliver a prescribed dose to a point on an isodose l ine as calculated by a commercial treatment planning system. Calibrati on-spreadsheet programs have been developed to perform the calculation s necessary for the output calibration of cobalt and high-energy photo n and electron beams according to the TG-BI protocol. The user must in dicate which beam, electrometer, chamber, phantom material, temperatur e, pressure and depth of measurement that apply. Radiosurgery - the MU per are is calculated based on the following: the average depth per a re as obtained from a commercial radiosurgery program, the collimator size, and the prescription dose. TBI-The patient's width is entered in to the spreadsheet program, which then calculates the My needed to del iver a prescribed dose to the midline.