The Application And Therapeutic Effect Of Whole Body Radiotherapy In Pre-treatment Of Hematopoietic Stem Cell Transplantation

Objective To develop the feasibility and dosimetry characteristics of a volumetric arc therapy(VMAT)-total body irradiation(TBI)technique.Methods VMAT technique was performed for fifteen patients accepted a TBI therapy as a preconditioning regimen of hemapoietic stem cell transplantation at BenQ Medical Center,between August 1st,2012 and January 31th,2015.Eclipse 10.0.Treatment planning systems was employed to perform treatment plan.The VMAT plan consisted of four centers:the head and neck,the chest,the abdomen and the pelvis,each with a 360° arcs.The prescription dose was 12Gy/6F.The homogeneity of planning target volume(PTV)and organs at risk(OAR)was measured by Dmean,Dmax,Dmin,dose volume histograms(DVH)curve.Monitor units(MU),the bean time and total treatment time were prescribed to ensure the efficiency of the VMAT planning.Finally,the 2D ionization chamber array I'mRT MatrixX was used to verify the VMAT treatment.Results In all patients,there were average MUs of 2308±210.7MU,and dose rate of 400cGy/min.The total treatment delivery time was approximately 30min.Using this technique,the Dmean for PTV was 12.58±0.45 Gy,with a range of 11.27±0.13 Gy to 5.35±0.65 Gy.Simultaneously,a considerable organ at risk dose reduction was observed by using this planning.Conclusion The results from our study suggest VMAT technique could obtain dose conformality of PTV,reduced the dose of OAR,and,most importantly,improved treatment delivery efficiency.And it is expected to facilitate the clinical transition of TBI for the patients with hematologic malignancies.Objectives:Total body irradiation(TBI)is widely used as a preconditioning regimen of hemapoietic stem cell transplantation(HSCT)in treatment of hematological malignancies.However,the use of TBI is limited by the toxicity to the critical organs.The purpose of this study is to observe the efficacy and the major adverse reactions of a novel TBI with an Volumetric modulated arc therapy(VMAT)technique.Methods:15 patients who underwent a TBI therapy as a preconditioning regimen of HSCT at the Department of Radiation Oncology,BenQ Medical Center,Nanjing Medical University,between August 1st,2012 and January 31st,2015,were recruited for this study.In this study,TBI used Fractionated radiotherapy and VMAT technique,and Eclipse 10.0 Treatment Planning System is employed to perform Treatment planning.The clinical target volume(CTV)contains total narrow,main lymphatic chains,testis and spleen and the external expansion on the CTV(3mm)is defined.In this study,the TBI total dose is up to 12 Gy,2 Gy twice a day for 3 days.Results:With a median follow-up of 17 months(range 1-30 months),Neutrophils of 13 patients(13/15)has increased and the absolute number is over 20×10^9/L in 12-37 days post-transplant.Meanwhile,PCR analyze also show a donate karyotype,indicating that the therapy was successful.Except one suffered a severe(grade 3)radiation enteritis,patients accepted TBI therapy have mild adverse reactions,such as oral mucosal injury and mild diarrhea,which were tolerable.Conclusion:TBI with Fractionated radiotherapy and VMAT technique is useful as a HSCT pretreatment in clinic,while limited to the short observation period,the long-term efficacy and adverse reactions remains to be studied.