Proceedings of the Korean Society of Medical Physics Conference (한국의학물리학회:학술대회논문집)
- 2002.09a
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- Pages.68-73
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- 2002
A Monitor Unit Verification Calculation in IMRT as a Dosimetry QA
- Kung, J.H. (Massachusetts General Hospital, Boston, MA, Harvard Medical School, Boston, MA) ;
- Chen, G.T.Y. (Massachusetts General Hospital, Boston, MA, Harvard Medical School, Boston, MA) ;
- Kuchnir, F.T. (Department of Radiation and Cellular Oncology, The University of Chicago)
- Published : 2002.09.01
Abstract
In standard teletherapy, a treatment plan is generated with the aid of a treatment planning system, but it is common to perform an independent monitor unit verification calculation (MUVC). In exact analogy, we propose and demonstrate that a simple and accurate MUVC in Intensity Modulated Radiotherapy (IMRT) is possible. We introduce a concept of Modified Clarkson Integration (MCI). In MCI, we exploit the rotational symmetry of scattering to simplify the dose calculation. For dose calculation along a central axis (CAX), we first replace the incident IMRT fluence by an azimuthally averaged fluence. Second, the Clarkson Integration is carried over annular sectors instead of over pie sectors. We wrote a computer code, implementing the MCI technique, in order to perform a MUVC for IMRT purposes. We applied the code to IMRT plans generated by CORVUS. The input to the code consists of CORVUS plan data (e.g., DMLC files, jaw settings, MU for each IMRT field, depth to isocenter for each IMRT field), and the output is dose contribution by individual IMRT field to the isocenter. The code uses measured beam data for Sc, Sp, TPR, (D/Mu)
Keywords
- Intensity Modulated Radiotherapy;
- Monitor Unit Calculation;
- Dosimetry;
- Quality Assurance;
- Hand Calculation