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SU‐FF‐T‐285: Independent Monitor Unit Verification with the RadCalc® Program of Serial Tomotherapy IMRT Treatment Delivery
Author(s) -
Workie D,
Sehgal V,
He B,
AlGhazi M
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2241202
Subject(s) - tomotherapy , multileaf collimator , imaging phantom , ionization chamber , monitor unit , quality assurance , nuclear medicine , collimator , radiation treatment planning , dosimetry , medical physics , linear particle accelerator , software , medicine , computer science , radiation therapy , beam (structure) , physics , optics , radiology , pathology , ionization , programming language , ion , external quality assessment , quantum mechanics
Purpose: To present our initial experience with the implementation of commercially available independent monitor unit (MU) verification calculation software (RadCalc®) for dose verification for patients undergoing IMRT (serial tomotherapy) treatments planned using a commercially available IMRT planning system (CORVUS® 6.0) and delivered using the multileaf intensity modulating collimator (MIMiC) delivery device. Method and Materials: As a first step we defined a separate machine within the RadCalc® software to facilitate the dose verification process. At our facility, serial tomotherapy is used to deliver IMRT treatments. This is accomplished using the MIMiC delivery device attached to a Varian 600C linear accelerator producing a 6 MV photon beam. Dosimetric data for this treatment machine which included collimator and phantom scatter factors (S c and S p ) and leaf transmission for the MIMiC were also incorporated in the RadCalc® Software. After the treatment plans are approved for treatment by the radiation oncologist a hybrid QA (quality assurance) plan is generated and delivered to an ion chamber and film placed in a rectangular solid water phantom of dimensions 30 cm × 30 cm × 22 cm. The phantom geometry was also defined in the RadCalc® software to facilitate dose calculation and comparison with the dose determined from ion‐chamber measurements. In this preliminary study a total of 13 patients undergoing IMRT treatment with the MIMiC were analyzed. Results: Initial results indicate a good agreement (within ±5%) between dose calculated from the hybrid plan, ion chamber measurements, and the dose calculated by the RadCalc® program. Conclusion: Based on initial results presented here we have set an action level of ±5% which will be reviewed and revised as necessary as we continue to acquire and analyze additional patient data.