Reducing the Doses of Cognitive and Stem Cell Compartments in the Radiotherapy for High Grade Gliomas with Comparison of Planning Systems in Intensity Modulated Radiotherapy

摘要

Purpose :Radiotherapy for patients with low or high grade gliomas increases local control and survival but causes dose dependent complications and long term side effects related to neuro-endocrine tissues. The present study aimed at investigating the role of constraining the contralateral uninvolved brain hemisphere (CLB) by comparing different planning tecniques in intensity modulated radiotherapy (IMRT). Methods :The planning target volumes and CLB volumes of nine patients with high grade glial tumors were delineated. The planning target volume dose defined as 60 Gy in 30 fractions (>95% volume to receive 60 Gy ) and CLB were constrained (<10% volume to receive 40 Gy). Beam angle optimization and inverse planned IMRT plans were calculated and dose volume histograms were compared. Results :By constraining CLB in inversed planned IMRT, the volume irradiated greater than 40 Gy of CLB reduced (3,7% vs 6,4%), the volume irradiated greater than 30 Gy of contralateral neural stem cell compartments, the volume greater than 30 Gy of limbic circuit and the volume greater than 10 Gy of hippocampus reduced when we compared with beam angle optimization. Conclusions :We originally compared CLB and ipsilateral tumor involved brain hemisphere doses with sparing CLB and IMRT planning techniques in this study. Dose reduction of cognitive and stem cell compartments by sparing CLB may protect patients from the long term neurocognitive deficits, vascular side effects, secondary cancers and it may help the future clinical studies.