Methods for image guided and intensity modulated radiation therapy in high-risk abdominal neuroblastoma

Purpose: Our purpose was to determine methods for image guided intensity modulated radiation therapy (IMRT) in pediatric abdominal high-risk neuroblastoma and to quantify the degree of normal tissue dose reduction by using volumes compliant with International Commission on Radiation Units and Measurements (ICRU) Report 62. Methods and Materials: Eight consecutive children with high-risk abdominal neuroblastoma (median age, 2.5 years; range, 20 months-5 years) were treated with IMRT using volumes accounting for physiologic motion (IMRT_phys) and daily pretreatment cone beam computed tomographic localization. Comparative IMRT planning using conventional volumes (IMRT_std) provided quantification for dose reduction to normal tissues. Results: The IMRT_phys plan reduced the mean planning target volume from 668.8+/-200.6 cc to 393.0+/-132.5 cc (P b.001) and reduced mean body V50 from 1774.4+/-383.9 cc to 1385.7 +/- 365.7 cc (P b.001). The IMRT_phys plan reduced the percent mean dose to the ipsilateral kidney from 70.1%+/-4.3% to 66.0%+/-5.2% (P =. 002); that to the contralateral kidney was reduced from 56.3%+/-7.0% to 40.7%+/-9.5% (P = .001), and that to the liver was reduced from 57.8%+/-16.0% to 22.1%+/-6.8% (P =.001). Conclusions: For IMRT planning, ICRU 62-compliant volume definition with image guidance in the pediatric abdomen enables volumetric reduction of the planning target volume and reduces normal tissue dose. These methods provide a framework for more conformal treatment planning in the pediatric abdomen. (C) 2013 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.