ObjectiveTo investigate the feasibility of using Intensity-modulated radiotherapy （IMRT） for newly diagnosed stage Ⅳb nasopharyngeal carcinomas with bone metastasis. MethodsFifteen cases of stage Ⅳb nasopharyngeal carcinoma with bone metastasis which were delivered under the Tomotherapy （TOMO） were selected. Under the same prescription dose requirements and dose constraints in TOMO， the IMRT plan was designed on Eclipse treatment planning system. For the target of nasopharyngeal site， 9 fix-gantry angle beams were used， and 7 or 9 fix-gantry angle beams were for the site of bone metastasis. The dosimetric indexes for plan comparison included prescription dose coverage and high dose coverage of the targets， homogeneity index and conformal index in target volume， the key dosimetric index for organs at risk， the plan delivery efficiency indexes including the MU and plan delivery time. Data from the two groups were compared by paired t-test. ResultsTo the gross targets of the nasopharyngeal site， both IMRT and TOMO plans had comparable dose coverage. But compared with TOMO plan， IMRT plan had a little worse performance in the dose uniformity and had a higher dose in targets. To the organs at risk， the D1% of spinal cord and brain stem in IMRT plan was higher than that in TOMO plan， but the average dose of parotids for IMRT plan was lower than that for TOMO plan. All the dosimetric indexes for plan evaluation were within the clinical dose tolerance. ConclusionsFor radiotherapy of newly diagnosed stage Ⅳb nasopharyngeal carcinomas with bone metastasis， the IMRT technique could provide adequate target dose coverage and normal organ sparing compared with helical tomotherapy plan. IMRT technique could be a feasible alternative to helical tomotherapy for this treatment.