Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
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To investigate the dosimetric impact of using 4D CT and multiphase (helical) CT images for treatment planning target definition and the daily target coverage in hypofractionated stereotactic body radiotherapy (SBRT) of lung cancer. ⋯ Compared to the conventional approach using helical images for target definition, 4D CT and multiphase 3D CT have the advantage to provide patient-specific tumor motion information, based on which such designed PTVs could ensure daily target coverage. 4D CT-based treatment planning further reduces the amount of normal lung being irradiated while still providing a good target coverage when image guidance is used.
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To verify the potential of aperture-based intensity-modulated radiotherapy (AB-IMRT) to realize dose escalation plans for non-preselected non-small-cell lung cancer (NSCLC) patients, using photon beam energy optimization. ⋯ The AB-IMRT system can successfully realize dose escalation for a sizeable number of cases. Plans produced contained few large segments, and are applicable to a wide range of tumor volumes and locations.
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Help identify and define potential normal tissue dose constraints to minimize the mortality and morbidity of hypofractionated lung radiotherapy. ⋯ The radiobiological analysis based on the LQ method, biologically equivalent dose nomenclature, and isodose-based method proposed in this study simplifies normal tissue dose constraints and treatment plan evaluation. This may also be applied to extrathoracic hypofractionated radiotherapy. Prospective validation of these preliminary thoracic normal tissue dose constraints for hypofractionated lung radiotherapy is necessary.
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We evaluated the relationship between the mean lung dose (MLD) and the incidence of radiation pneumonitis (RP) after stereotactic body radiation therapy (SBRT), and compared this with conventional fractionated radiation therapy (CFRT). ⋯ We derived a significant dose-response relationship between the risk of RP and the MLD for SBRT from the clinical data. This relation was not significantly different from the dose-response relation for CFRT, although statistical analysis was hampered by the low number of patients in the high dose range.