Design, fabrication, and testing of a fiduciary tray to be used with the multileaf intensity-modulating collimator for portal film localization.

The purpose of this study was to design, fabricate, and test a fiduciary tray to be used for portal film localization using the multileaf intensity-modulating collimator (MIMiC) developed by NOMOS Corporation of Sewickley, PA. The MIMiC is a tertiary collimator that is utilized in intensity-modulated radiation therapy (IMRT) treatments. At this time, no MIMiC fiduciary tray exists for commercial use. Due to the escalation of dose in IMRT treatments, the need for accurate localization is of utmost importance. A slight error in interpretation could lead to significant errors in dosimetric coverage of the target volume and possible overdosing of normal tissues. A fiduciary tray that fits onto the MIMiC was designed. Special attention was given to ensure that treatment could not be accidentally given with the tray in place. Various localization tests were administered to ensure accuracy for brain and pelvic treatments. The fiduciary tray should directly impact the daily operations for not only the radiation therapists but also the radiation oncologists by aiding in the direct comparison of setup films to weekly port films.