Discrepancies between Calculated and Delivered Dose Distributions of Respiratory Gated IMRT Fields according to the Target Motion Ranges for Lung and Liver Cancer Patients
Progress in Medical Physics 2014³â 25±Ç 4È£ p.242 ~ p.247
±è¿µ±¹(Kim Young-kuk) - Dong-A University Department of Physics
³ëÅÂÀÍ(Ro Tae-Ik) - Dong-A University Department of Physics
Á¤Å½Ä(Jeung Tae-Sig) - Kosin University College of Medicine Department of Radiation Oncology
¸¶¼±¿µ(Ma Sun-Young) - Kosin University College of Medicine Department of Radiation Oncology
ÃÖÁöÈÆ(Choi Ji-Hoon) - Kosin University College of Medicine Department of Radiation Oncology
ÀÓ»ó¿í(Lim Sang-Wook) - Kosin University College of Medicine Department of Radiation Oncology
Abstract
To see the discrepancies between the calculated and the delivered dose distribution of IMRT fields for respiratory-induced moving target according to the motion ranges. Four IMRT plans in which there are five fields, for lung and liver patients were selected. The gantry angles were set to 0¡Æ for every field and recalculated using TPS (Eclipse Ver 8.1, Varian Medical Systems, Inc., USA). The ion-chamber array detector (MatriXX, IBA Dosimetry, Germany) was placed on the respiratory simulating platform and made it to move with ranges of 1, 2, and 3 cm, respectively. The IMRT fields were delivered to the detector with 30~70% gating windows. The comparison was performed by gamma index with tolerance of 3 mm and 3%. The average pass rate was 98.63% when there's no motion. When 1.0, 2.0, 3.0 cm motion ranges were simulated, the average pass rate were 98.59%, 97.82%, and 95.84%, respectively. Therefore, ITV margin should be increased or gating windows should be decreased for targets with large motion ranges.
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Gated radiation therapy, IMRT, Gamma index, Moving phantom
KMID :
1038720140250040242
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À¯È¿¼º°á°ú(Recomendation)
³»ºÎÇ¥ÀûºÎÇÇ(internal target volume, ITV) margin should be increased or gating windows should be decreased for targets with large motion ranges.