title: Radiation studies on multicellular tumour spheroids derived from human neuroblastoma: absence of sparing effect of dose fractionation.
abstract: In vitro experiments were carried out to compare the effects of single-dose and split-dose irradiation on a cell line (NB1-G) derived from human neuroblastoma and grown as multicellular tumour spheroids (MTS). The radiation response was evaluated in terms of regrowth delay; estimates of in situ cell survival were made by back-extrapolation of regrowth curves. These studies showed no significant difference in the effectiveness of single as compared to split dose irradiation i.e. no sparing effect of fractionation. If MTS constitute a realistic model for micrometastases in vivo, these results provide a radiobiological rationale for hyperfractionated treatment regimes in the adjuvant radiotherapy of neuroblastoma.
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D066298:In Vitro Techniques; D008938:Mitosis / Q000528:radiation effects; D009447:Neuroblastoma / Q000503:physiopathology*