Three-dimensional conformal vs. intensity-modulated radiotherapy in head-and-neck cancer patients: comparative analysis of dosimetric and technical parameters.

摘要: Abstract Background and purpose The use of intensity-modulated radiotherapy (IMRT) is now widely advocated for the treatment head-and-neck cancers, to increase therapeutic ratio used as sole modality or in combination with chemotherapy. This report aims summarize technical dosimetric factors be taken into consideration assess respective advantages various high conformality treatments radiotherapy, especially framework quality assurance procedures. Materials methods Twenty-six cancer patients were irradiated following a feasibility internal protocol IMRT. Treatments performed either static step-and-shoot (20) dynamic sliding window (6) techniques on 6 MV Varian Clinac equipped multileaf collimator 80 leaves. Dose plans computed using commercial planning systems: MDS-Nordion Helax-TMS cases Eclipse cases. evaluated terms physical quantities based dose–volume histograms isodose distributions. Each IMRT plan was also compared reference 3D conformal therapy (3DCRT). Results Elective target volumes ranged from 530 1151 cm 3 mean 780 ± 141 . Boost 248 832 537 165 Thirty-two dose generated technique 10 dynamic. In mode, 6.8 3.4 fields applied average 12.5 1.3 segments per field. 264 56 MU Gy erogated, whereas 387 126 147 20 3DCRT plans. For all general, conformity improved (e.g. V 95 increased 85% 93% p = 0.002). Irradiation parotid glands spinal cord improved, well: parotids, D 2/3V reduced 59 41 ( max about 40 30