A modified VMAT adaptive radiotherapy for nasopharyngeal cancer patients based on CT-CT image fusion

Radiation Oncology

Congying Xie¹  Huawei Yan¹  Jinling Yi¹  Yongqiang Zhou¹  Ce Han¹  Xiance Jin¹ 

[1] Radiotherapy and Chemotherapy, Department of the 1st Affiliated Hospital of Wenzhou Medical University, No.2 Fuxue Lane, Wenzhou 325000, China

关键词: Deformable registration;    CT-CT image fusion;    Volumetric modulated arc therapy;    Adaptive radiotherapy;    Nasopharyngeal cancer;   

Others  :  829642
DOI  :  10.1186/1748-717X-8-277

 received in 2013-06-18, accepted in 2013-11-24,  发布年份 2013

【 摘 要 】

Background

To investigate the feasibility and benefits of a modified adaptive radiotherapy (ART) by replanning in the initial CT (iCT) with new contours from a repeat CT (rCT) based on CT-CT image fusion for nasopharyngeal cancer (NPC) patients underwent volumetric modulated arc radiotherapy (VMAT).

Materials and methods

Nine NPC patients underwent VMAT treatment with a rCT at 23rd fraction were enrolled in this study. Dosimetric differences for replanning VMAT plans in the iCT and in the rCT were compared. Volumetric and dosimetric changes of gross tumor volume (GTV) and organs at risk (OARs) of this modified ART were also investigated.

Results

No dosimetric differences between replanning in the iCT and in the rCT were observed. The average volume of GTV decreased from 78.83 ± 38.42 cm³ in the iCT to 71.44 ± 37.46 cm³ in the rCT, but with no significant difference (p = 0.42).The average volume of the left and right parotid decreased from 19.91 ± 4.89 cm³ and 21.58 ± 6.16 cm³ in the iCT to 11.80 ± 2.79 cm³ and 13.29 ± 4.17 cm³ in the rCT (both p < 0.01), respectively. The volume of other OARs did not shrink very much. No significant differences on PTV_GTV and PTV_CTV coverage were observed for replanning with this modified ART. Compared to the initial plans, the average mean dose of the left and right parotid after re-optimization were decreased by 62.5 cGy (p = 0.05) and 67.3 cGy (p = 0.02), respectively, and the V5 (the volume receiving 5 Gy) of the left and right parotids were decreased by 7.8% (p = 0.01) and 11.2% (p = 0.001), respectively. There was no significant difference on the dose delivered to other OARs.

Conclusion

Patients with NPC undergoing VMAT have significant anatomic and dosimetric changes to parotids. Repeat CT as an anatomic changes reference and re-optimization in the iCT based on CT-CT image fusion was accurate enough to identify the volume changes and to ensure safe dose to parotids.

【 授权许可】

   
2013 Jin et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Kam MK, Chau RM, Suen J, Choi PH, Teo PM: Intensity-modulated radiotherapy in nasopharyngeal carcinoma: dosimetric advantage over conventional plans and feasibility of dose escalation. Int J Radiat Oncol Biol Phys 2003, 56:145-157.
• [2]Lee TF, Ting HM, Chao PJ, Fang FM: Dual arc volumetric-modulated arc radiotherapy (VMAT) of nasopharyngeal carcinomas: a simultaneous integrated boost treatment plan comparison with intensity-modulated radiotherapies and single arc VMAT. Clin Oncol 2012, 24:196-207.
• [3]Nutting CM, Morden JP, Harrington KJ, Urbano TG, Bhide SA, Clark C, Miles EA, Miah AB, Newbold K, Tanay M, Adab F, Jefferies SJ, Scrase C, Yap BK, A’Hern RP, Sydenham MA, Emson M, Hall E: PARSPORT trial management group: parotid-sparing intensity modulated versus conventional radiotherapy in head and neck cancer (PARSPORT): a phase 3 multicentre randomised controlled trial. Lancet Oncol 2011, 12:127-136.
• [4]Han CH, Chen YJ, Liu AL, Schultheiss TE, Wong JY: Actual dose variation of parotid glands and spinal cord for nasopharyngeal cancer patients during radiotherapy. Int J Radiat Oncol Biol Phys 2008, 70:1256-1262.
• [5]Schwartz DL: Current progress in adaptive radiation therapy for head and neck cancer. Curr Oncol Rep 2012, 14:139-147.
• [6]Hansen EK, Bucci MK, Quivey JM, Weinberg V, Xia P: Repeated CT imaging and replanning during the course of IMRT for head-and-neck cancer. Int J Radiat Oncol Biol Phys 2006, 64:355-362.
• [7]Wang W, Yang H, Hu W, Shan G, Ding W, Yu C, Wang B, Wang X, Xu Q: Clinical study of the necessity of replanning before the 25th fraction during the course of intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys 2010, 77:617-621.
• [8]Zhao L, Wan Q, Zhou Y, Deng X, Xie C, Wu S: The role of replanning in fractioned intensity modulated radiotherapy for nasopharyngeal carcinoma. Radioth and Oncol 2011, 98:23-27.
• [9]Bhide SA, Davies M, Burke K, McNair HA, Hansen V, Barbachano Y, El-Hariry IA, Newbold K, Harrington KJ, Nutting CM: Weekly volume and dosimetric changes during chemoradiotherapy with intensity-modulated radiation therapy for head and neck cancer: a prospective observational study. Int J Radiat Oncol Biol Phys 2010, 76:1360-1368.
• [10]Steenbakkers R, Duppen J, Fitton I, Deurloo K, Zijp L, Eisbruch A, Nowak P, Van Herk M, Rasch C: Observer variation in delineation of nasopharyngeal carcinoma for radiotherapy: a 3-D analysis. Int J Radiat Oncol Biol Phys 2004, 60:S160-S161.
• [11]Fung WWK, Wu VWC: Teo PML: Dosimetric evaluation of a three-phase adaptive radiotherapy for nasopharyngeal carcinoma using helical tomotherapy. Med Dosim 2012, 37:92-97.
• [12]Wu SX, Xie CY, Jin XC, Zhang P: Simultaneous modulated accelerated radiation therapy in the treatment of nasopharyngeal cancer: a local center’s experience. Int J Radiat Oncol Biol Phys 2006, 66:s40-s46.
• [13]Jin X, Yi J, Zhou Y, Yan H, Han C, Xie C: Comparison of whole field simultaneous integrated boost VMAT and IMRT in the treatment of nasopharyngeal cancer, Medical Dosimetry. 2013. http://dx.doi.org/10.1016/j.meddos.2013.05.004 webcite
• [14]Barker JL, Garden AS, Ang KK, O’Daniel JC, Wang H, Court LE, Morrison WH, Rosenthal DI, Chao KS, Tucker SL, Mohan R, Dong L: Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/ linear accelerator system. Int J Radiat Oncol Biol Phys 2004, 59:960-970.
• [15]Ricchetti F, Wu B, McNutt T, Wong J, Forastiere A, Marur S, Starmer H, Sanguineti G: Volume change of selected organs at risk during IMRT for oropharyngeal cancer. Int J Radiat Oncol Biol Phys 2011, 81:161-168.
• [16]Lee C, Langen KM, Lu W, Haimerl J, Schnarr E, Ruchala KJ, Olivera GH, Meeks SL, Kupelian PA, Shellenberger TD, Mañon RR: Evaluation of geometric changes of parotid glands during head and neck cancer radiotherapy using daily MVCT and automatic deformable registration. Radiother Oncol 2008, 89:81-88.
• [17]Vasquez Osorio EM, Hoogeman MS, Al-Mamgani A, Tequh DN, Levendag PC, Heijmen BJ: Local anatomic changes in parotid and submandibular glands during radiotherapy for oropharynx cancer and correlation with dose, studied in detail with nonrigid registration. Int J Radiat Oncol Biol Phys 2008, 70:875-882.
• [18]Schwartz DL, Dong L: Adaptive radiation therapy for head and neck cancer-can an old goal evolve into a new standard? J Oncol 2011, 2011:1-14.