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Session: Therapy General ePoster Viewing [Return to Session]

Evaluation of Surface Dose Prediction Accuracy of Precision Radixact Tomotherapy Treatment Planning System Using OSL Nanodots

A Alphonse*, S Pokharel, M Kasper, S Richter, S Rana, Lynn Cancer Institute, Boca Raton Regional Hospital, Boca Raton, FL


PO-GePV-T-249 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: To evaluate the accuracy of the surface dose calculated by the Precision treatment planning system for Radixact tomotherapy by comparing against the measured dose from optically stimulated luminescence (OSL) technology via nanodots.

Methods: A unique approach was utilized to place the nanodots in the area of interest on the patient’s skin. Specifically, the exact locations of the nanodots placement were marked with a sharpie marker on the skin surface of a patient. Then small metallic BBs were placed on the marked locations designating the area of interest. A localization KVCT or MVCT that was used for anatomical set-up was then generated. Upon completion of scan verification for set-up accuracy, the metallic BBs were then removed and replaced with the OSL nanodots. The patient was treated exposing the nanodots at the exact position of interest. The next step was to perform a rigid registration of the localization scan with the planning CT containing the planned treatment dose. This registration displayed the exact location of the OSL nanodots via the BBs. Within the planning CT containing the planned treatment dose, the calculated dose to the BBs was obtained. The OSL nanodots were then sent out to the lab in order to obtain the measured dose.

Results: The measured dose using the OSL technology via nanodots were about ±1.5% different from the calculated dose from the Precision planning system.

Conclusion: The difference between the calculated (Precision) and measured (nanodots) doses on the patient skin was clinically acceptable. The nanodot measurements on additional patients will be performed to confirm the accuracy of the Precision planning system in predicting surface dose for Radixact tomotherapy treatment.


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