演題抄録

International Session(Poster)

開催概要
開催回
第51回・2013年・京都
 

A Dosimetric Comparison of Radiotherapies for Paraaortic Lymph Node Metastasis

演題番号 : ISP-20

[筆頭演者]
Seok Ho Lee:1 
[共同演者]
Seung Heon Lee:1、KiHoon Sung:1、Choi Jin-Ho :1、Lee Kyu Chan :1

1:Radiation Oncology, Gachon University Gil Hospital, Korea

 

Purpose: The aim of this study is to compare the dosimetric differences of volumetric modulated arc therapy (VMAT), intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D-CRT) for patients with paraaortic lymph nodes (PALNs) metastases.Materials and Methods: Five patients of PALNs metastases were enrolled in this study. Dosimetric values for comparision of VMAT, IMRT and 3D-CRT were calculated for total doses of 50 Gy using 2.5 Gy/day. The parameters included the quality of coverage (QOC), conformal index (CI), homogeneity index (HI) and hot spot (V105%) for the planning target volume (PTV) as well as the monitor units (MUs) for plan efficiency. The mean dose (Dmean) for the organs at risk (OAR) and the maximal dose at 1% volume (D1%) for the spinal cord were evaluated. Results: Summated PTV were 49 to 334.6 cc (median 111.7 cc). The QOC of VMAT, IMRT and 3D-CRT were 0.83±0.10, 0.75±0.05 and 0.83±0.13, respectively (p=0.228). The CI of VMAT, IMRT and 3D-CRT were 1.12±0.11, 1.01±0.12 and 1.62±0.79, respectively (p=0.182). The HI of VMAT, IMRT and 3D-CRT were 1.46±0.28, 1.38±0.31 and 1.03±0.02, respectively (p=0.009). The averaged MUs of VMAT, IMRT and 3D-CRT were 826.4±183.0, 920±222.2 and 353.6±87.2, respectively (p=0.008). The Dmean of the liver for VMAT, IMRT and 3D-CRT were 4.49±3.37 Gy, 4.87±3.44 Gy and 6.39±5.06 Gy, respectively (p=0.878). The maximum dose to the spinal cord were 19.79±5.58 Gy for VMAT, 18.58±3.79 Gy for IMRT, and 29.15±1.03 Gy for 3D-CRT (p=0.114). Conclusion: In patients with PALNs metastases, VMAT and IMRT showed more conformal PTV coverage and more liver and spinal cord sparing compared with 3D-CRT. 3D-CRT provided significantly more homogeneous PTV coverage and showed significantly lower MUs compared with VMAT and IMRT. More patients should be analyzed to confirm these results.

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