The effect of multileaf collimator leaf width on the radiosurgery planning for spine lesion treatment in terms of the modulated techniques and target complexity

Radiation Oncology

Seok Hyun Son²  Gi Woong Lee¹  Soo-Min Chae¹ 

[1] Department of Radiation Oncology, Cheju Halla General Hospital, Jeju, Korea;Department of Radiation Oncology, Incheon St. Mary’s hospital, College of Medicine, the Catholic University of Korea, Incheon, Korea

关键词: Target complexity;    Volumetric-modulated arc therapy;    Intensity-modulated radiotherapy;    Multileaf collimator;   

Others  :  811717
DOI  :  10.1186/1748-717X-9-72

 received in 2013-06-18, accepted in 2014-03-02,  发布年份 2014

【 摘 要 】

Purpose

We aim to evaluate the effects of multileaf collimator (MLC) leaf width (5 mm vs. 2.5 mm) on the radiosurgery planning for the treatment of spine lesions according to the modulated techniques (intensity-modulated radiotherapy [IMRT] vs. volumetric-modulated arc therapy [VMAT]) and the complexity of the target shape.

Methods

For this study, artificial spinal lesions were contoured and used for treatment plans. Three spinal levels (C5, T5, and L2 spines) were selected, and four types of target shapes reflecting the complexity of lesions were contoured. The treatment plans were performed using 2.5-mm and 5-mm MLCs, and also using both static IMRT and VMAT. In total, 48 treatment plans were established. The efficacy of each treatment plan was compared using target volume coverage (TVC), conformity index (CI), dose gradient index (GI), and V_30%.

Results

When the 5-mm MLC was replaced by the 2.5-mm MLC, TVC and GI improved significantly by 5.68% and 6.25%, respectively, while CI did not improve. With a smaller MLC leaf width, the improvement ratios of the TVC were larger in IMRT than VMAT (8.38% vs. 2.97%). In addition, the TVC was improved by 14.42-16.74% in target type 4 compared to the other target types. These improvements were larger in IMRT than in VMAT (27.99% vs. 6.34%). The V_30% was not statistically different between IMRT and VMAT according to the MLC leaf widths and the types of target.

Conclusion

The smaller MLC leaf width provided improved target coverage in both IMRT and VMAT, and its improvement was larger in IMRT than in VMAT. In addition, the smaller MLC leaf width was more effective for complex-shaped targets.

【 授权许可】

   
2014 Chae et al.; licensee BioMed Central Ltd.

【 图 表 】

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