[ Special series on Nasopharyngeal carcinoma ]
doi: 10.1186/s40880-015-0016-8
Dosimetric benefit to organs at risk following margin reductions in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy
Yan-Ping Mao, Wen-Jing Yin, Rui Guo, Guang-Shun Zhang, Jian-Lan Fang, Feng Chi, Zhen-Yu Qi, Meng-Zhong Liu, Jun Ma and Ying Sun
Department of Radiation Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, Guangdong, Peoples Republic of China
[Abstract]
Introduction
It is important to decrease the radiation exposure of normal tissue in intensity-modulated radiation therapy (IMRT). Minimizing planning target volume (PTV) margins with more precise target localization techniques can achieve this goal. This study aimed to quantify the extent to which organs at risk (OARs) are spared when using reduced margins in the treatment of nasopharyngeal carcinoma (NPC).
Methods
Two IMRT plans were regenerated for 40 patients with NPC based on two PTV margins, which were reduced or unchanged following cone beam computed tomography online correction. The reduced-margin plan was optimized based on maximal dose reduction to OARs without compromising target coverage. Dosimetric comparisons were evaluated in terms of target coverage and OAR sparing.
Results
Improvements in target coverage occurred with margin reduction, and significant improvements in dosimetric parameters were observed for all OARs (P<0.05) except for the right optic nerve, chiasm, and lens. Doses to OARs decreased at a rate of 1.5% to 7.7%. Sparing of the left parotid and right parotid, where the mean dose (Dmean) decreased at a rate of 7.1% and 7.7%, respectively, was greater than the sparing of other OARs.
Conclusions
Significant improvements in OAR sparing were observed with margin reduction, in addition to improvement in target coverage. The parotids benefited most from the online imaging-guided approach.
Introduction
It is important to decrease the radiation exposure of normal tissue in intensity-modulated radiation therapy (IMRT). Minimizing planning target volume (PTV) margins with more precise target localization techniques can achieve this goal. This study aimed to quantify the extent to which organs at risk (OARs) are spared when using reduced margins in the treatment of nasopharyngeal carcinoma (NPC).
Methods
Two IMRT plans were regenerated for 40 patients with NPC based on two PTV margins, which were reduced or unchanged following cone beam computed tomography online correction. The reduced-margin plan was optimized based on maximal dose reduction to OARs without compromising target coverage. Dosimetric comparisons were evaluated in terms of target coverage and OAR sparing.
Results
Improvements in target coverage occurred with margin reduction, and significant improvements in dosimetric parameters were observed for all OARs (P<0.05) except for the right optic nerve, chiasm, and lens. Doses to OARs decreased at a rate of 1.5% to 7.7%. Sparing of the left parotid and right parotid, where the mean dose (Dmean) decreased at a rate of 7.1% and 7.7%, respectively, was greater than the sparing of other OARs.
Conclusions
Significant improvements in OAR sparing were observed with margin reduction, in addition to improvement in target coverage. The parotids benefited most from the online imaging-guided approach.
Chinese Journal of Cancer 2015, Volume: 34, Issue 5
[ PDF Full-text ]
[ Html full-text / Citation export] (BioMed Central)
[Google Scholar]
[ More articles of the special series on Nasopharyngeal carcinoma ]
Cite this article
Yan-Ping Mao, Wen-Jing Yin, Rui Guo, Guang-Shun Zhang, Jian-Lan Fang, Feng Chi, Zhen-Yu Qi, Meng-Zhong Liu, Jun Ma and Ying Sun. Dosimetric benefit to organs at risk following margin reductions in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy. Chin J Cancer. 2015, 34:16. doi:10.1186/s40880-015-0016-8
Export citations
EndNote
[ Html full-text / Citation export] (BioMed Central)
[Google Scholar]
[ More articles of the special series on Nasopharyngeal carcinoma ]
Cite this article
Yan-Ping Mao, Wen-Jing Yin, Rui Guo, Guang-Shun Zhang, Jian-Lan Fang, Feng Chi, Zhen-Yu Qi, Meng-Zhong Liu, Jun Ma and Ying Sun. Dosimetric benefit to organs at risk following margin reductions in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy. Chin J Cancer. 2015, 34:16. doi:10.1186/s40880-015-0016-8
Export citations
EndNote
SHARE THIS ARTICLE
Comments:
