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Abstract
The position of the internal organs can change continually and periodically inside the body due to the respiration. To reduce the respiration induced uncertainty of dose localization, one can use a respiratory gated radiotherapy where a radiation beam is exposed during the specific time of period. The main disadvantage of this method is that it usually requests a long treatment time, the massive effort during the treatment and the limitation of the patient selection. In this sense, the combination of the real-time position management (RPM) system and the volumetric intensity modulated radiotherapy (RapidArc) is promising since it provides a short treatment time compared with the conventional respiratory gated treatments. In this study, we evaluated the accuracy of the respiratory gated RapidArc treatment. Total sic patient cases were used for this study and each case was planned by RapidArc technique using varian ECLIPSE v8.6 planning machine. For the Quality Assurance (QA), a MatriXX detector and I'mRT software were used. The results show that more than 97% of area gives the gamma value less than one with 3% dose and 3 mm distance to agreement condition, which indicates the measured dose is well matched with the treatment plan's dose distribution for the gated RapidArc treatment cases.
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Fig. 2.
(a) Radiation Therapy Planning (RTP) result using by ECLIPSE, (b) Dose distribution of same patient radiation therapy plan when it is projected into MatriXX detector.
Fig. 3.
(a) 2 dimensional dose distribution of the measurement by MatriXX, (b) dose comparison of x-axis profile between measurement and RTP plan, (c) 2 dimensional dose distribution of the RTP plan by ECLIPSE, (d) gamma distribution for same sample.
Table 1.
Information of the patient radiotherapy plan (1 arc=360o, 2 arc=720o).
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