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http://dx.doi.org/10.14316/pmp.2015.26.3.153

Evaluation of Dosimetric Leaf Gap (DLG) at Different Depths for Dynamic IMRT  

Chang, Kyung Hwan (Department of Radiation Oncology, Asan Medical Center)
Kwak, Jungwon (Department of Radiation Oncology, Asan Medical Center)
Cho, Byungchul (Department of Radiation Oncology, Asan Medical Center)
Jeong, Chiyoung (Department of Radiation Oncology, Asan Medical Center)
Bae, Jae Beom (Department of Radiation Oncology, Asan Medical Center)
Yoon, Sang Min (Department of Radiation Oncology, Asan Medical Center)
Lee, Sang-wook (Department of Radiation Oncology, Asan Medical Center)
Publication Information
Progress in Medical Physics / v.26, no.3, 2015 , pp. 153-159 More about this Journal
Abstract
This study is to evaluate thedosiemtric leaf gap (DLG) at different depths for dynamic intensity-modulated radiation therapy (IMRT) in order to evaluate the absolute dose and dose distribution according to the different positions of tumors and compare the measured and planned the multileaf collimator (MLC) transmission factor (T.F.) and DLG values. We used the 6 MV and 15 MV photon beam from linear accelerator with a Millenium 120 MLC system. After the import the DICOM RT files, we measured the absolute dose at different depths (2 cm, 5 cm, 10 cm, and 15 cm) to calculate the MLC T. F. and DLG. For 6 MV photon beam, the measured both MLC T. F. and DLG were increased with the increase the measured depths. When applying to treatment planning systemas fixed transmission factor with its value measured under the reference condition at depth of 5 cm, although the difference fixed and varied transmission factor is not significant, the dosiemtric effect could be presented according to the depth that the tumor is placed. Therefore, we are planning to investigate the treatment planning system whichthe T. F. and DLG factor according to at the different depths can be applied in the patient-specific treatment plan.
Keywords
Dosimetric leaf gap (DLG); MLC transmission factor; MLC files; Intensity-modulated radiation therapy (IMRT); Patient-specific plan;
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