Comparison Of The Target Volumeand Clinical Difference Of Total Body Irriadiation For Acute Lymphoblastic Leukemia Before Hematopoietic Stem Cell Transplantation

Objective:Two different radiotherapy regimens(TBI,TMLI)were carried out in 10 patients with acute lymphoblastic leukemia before hematopoietic stem cell transplantation.By comparing the differences between the target volume ? treatment plan,clinical response and the clinical effect,then evaluation the advantages and disadvantages of the two radiotherapy regimens in clinical treatment,and provide the theoretical basis for clinical treatment.Methods:This study retrospectively selected10 cases of total body irriadiationbefore hematopoietic stem cell transplantation in the first Affiliated Hospital of Zhengzhou University from May 2016 to December 2016.The patients were all meet the following requirements: All patients underwent bone marrow aspiration biopsy with clear pathological diagnosis of acute lymphoblastic leukemia;All patients received high-dose chemotherapy and intrathecal chemotherapy before radiotherapy.CT scan images were imported into Eclipse workstation,then outline the clinical target volumeon the CT images,including TBI and TMLI two different radiotherapyprograms.TBI target volumeis the whole body except for the normal organs;TMLI clinical target volume is defined as the whole body bone,the main lymph node chain and spleen,consider retaining the patient reproductive function,in principle,we do not irradiate testes,but weneed to consider the chemotherapy and the will of the patients and their families.The organs at risk includbilateral lens and bilateral lung.PTV was obtained from CTV outside the expansion of 0.5cm,and all the patients were given 12 Gy / 6 F.PTV were evaluated as follows :theDmax,Dmean,D98,D95,D50,D02 and V12 of PTV.Bilateral lung were evaluated by Dmax,Dmean and V5,bilateral lens were evaluated by Dmax and Dmean.The clinical adverse effects(nausea,vomiting,anorexia,dry mouth,fever,diarrhea,rash)and clinical outcomes(transplant outcomes)were compared between the two radiotherapy programs.Results:1.Target:TMLI and TBI all meet the requirementsof the treatment,12 Gy dose distribution is uniform and the target volume are of high conformality.2.Organs at risk(OARs): All the organs at risk can be controlled within the normal range,in terms of lung dose,TMLI was lower than TBI.3.Clinical adverse reactions:TMLI and TBI are similar to the clinicaladverse reaction,the significant adverse reactions are nausea,vomiting(I-II level),anorexia,dry mouth,diarrhea,fever,rash,to nausea,treat with antiemetic,Diarrhea,rehydration and other drugs the patients fell better and they can tolerate.4.Clinical outcome: All patients with TBI were successfully transplanted,one patient died of serious rejection and infection after transplantation.Four patients with TMLI were successfully transplanted,no transplant rejection occurred.Conclusions:1.Both TBI and TMLI can meet the requirement of dose coverage,uniformity and conformability of target volume,D95 can meet the requirement of prescription dose 12 Gy,and all the dose of organs at risk are low.For lung protection,the average lung dose is lower in TMLI compare with TBI,but the dose of organs are all in the normal range.2.TBI and TMLI clinical response similar to the patients,both of the programs make patients fell mild to moderate adverse reactions,the more obvious is nausea,vomiting,anorexia and dry mouth,with the corresponding drug application they could tolerate.3.TBI and TMLI have similar transplantation effect,all the patient can be successfully transplanted.