ObjectiveTo compare planning quality,treatment efficiency and delivery accuracy for initial treated nasopharyngeal carcinoma (NPC) with step & shoot intensity modulated radiation therapy (ssIMRT) and volumetric modulated arc therapy (VMAT).These results will help make a clinic choice of the therapeutical technique.MethodsTwenty-six NPC cases were planned with the same dose prescription and objective constrains by means of 9-field ss-IMRT and VMAT respectively.Compare:( 1 ) plan dosimetric distribution,conformity index and homogeneity index of the targets,the average dose,maximum dose and interested dose-volume histograms of organs at risk (OAR) et al;(2) delivery times of the therapy plans ;(3) the accuracy of treatment plans dose verification.ResultsBoth therapeutical plans can achieve the clinic dosimetric demands.Compared to ss-IMRT,VMAT had less inferior target coverage.The CI and HI of the PGTV was 0.57 and 0.08 ( ss-IMRT),0.48 and 0.12 (VMAT) respectively ( t =-4.52,- 8.33,P =0.000,0.000).Except of brain stem,VMAT had higher mean dose and maximum dose of OARs than ss-IMRT (t=-9.57 - -3.71,P=0.000 -0.001).The spinal cord D1cc and parotids D50％ were increased by 11.9％ and 6.5％ averagely.The treatment times of ss-IMRT and VMAT were 803.7 s and 389.3 s respectively (t =24.12,P =0.000),while V MAT decreasing by 51.6％.The pass ratios of γ (3mm,3％ ) from the dose verification were 99.4％ (ss-IMRT) and 98.0％ (VMAT) respectively ( t =5.19,P =0.000).ConclusionsThe dose distribution of VMAT for initial treated nasopharyngeal carcinoma can achieve the clinic demands,but slightly worse than 9-field ss-IMRT.VMAT has the advantage of high efficiency and dosimetric accuracy.

Objective: To explore the clinical effects of split-thickness scalp and allogenic acellular dermal matrix (ADM) in repairing deep wounds of hands in patients with extremely extensive burns. Methods: Six patients with extremely extensive burns complicated by deep burn in hands were admitted to our department from December 2014 to December 2017, including 4 males and 2 females, aged 21 to 58 years. Their total burn areas were from 85% to 95% total body surface area (TBSA), and the sum of deep-partial thickness and full-thickness wounds was larger than 50% TBSA. Under general anesthesia, deep wounds of 10 dorsal hands were repaired by combined transplantation of split-thickness scalp and allogenic ADM in 4 to 6 weeks after injury. The skin grafting range was beyond the metacarpophalangeal joint, including partial dorsal digital deep wounds. Survival of skin grafts on dorsal hands, follow-up of hand shape and functional recovery were observed and recorded. Results: Six patients were successfully treated. There was no infection on the dorsal deep wounds of 10 hands after surgery, and the grafts survived well. During follow-up of 1 to 2 years after operation, there were no recurrent tension blisters or dorsal extension deformity of the metacarpophalangeal joints in 10 hands, the shape and function of hands recovered well, and hand Carroll scores were from 90 to 99 points, with functional levels of Ⅴ and Ⅵ. Conclusions The combined transplantation of split-thickness scalp and allogenic ADM is a good method for repairing deep hand wounds in patients with extremely extensive burns, which can alleviate the cicatrix hyperplasia and contracture of healed hand wounds, and improve the shape and function of hands.